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2017-11-21
Determination of spin Hall effect and spin diffusion length of Pt from self-consistent fitting of damping enhancement and inverse spin-orbit torque measurements
Understanding the evolution of spin-orbit torque (SOT) with increasing heavy-metal thickness in ferromagnet/normal metal (FM/NM) bilayers is critical for the development of magnetic memory based on SOT. However, several experiments have revealed an apparent discrepancy between damping enhancement and damping-like SOT r...
1711.07654v2
2019-09-19
Nonlinear energy loss in the oscillations of coated and uncoated bubbles: Role of thermal, radiation damping and encapsulating shell at various excitation pressures
A simple generalized model (GM) for coated bubbles accounting for the effect of compressibility of the liquid is presented. The GM was then coupled with nonlinear ODEs that account for the thermal effects. Starting with mass and momentum conservation equations for a bubbly liquid and using the GM, nonlinear pressure de...
1909.08793v1
2020-11-20
The effect of magnetic field on the damping of slow waves in the solar corona
Slow magnetoacoustic waves are routinely observed in astrophysical plasma systems such as the solar corona. As a slow wave propagates through a plasma, it modifies the equilibrium quantities of density, temperature, and magnetic field. In the corona and other plasma systems, the thermal equilibrium is comprised of a ba...
2011.10437v1
2023-06-22
Gilbert damping in metallic ferromagnets from Schwinger-Keldysh field theory: Intrinsically nonlocal and nonuniform, and made anisotropic by spin-orbit coupling
Understanding the origin of damping mechanisms in magnetization dynamics of metallic ferromagnets is a fundamental problem for nonequilibrium many-body physics of systems where quantum conduction electrons interact with localized spins assumed to be governed by the classical Landau-Lifshitz-Gilbert (LLG) equation. It i...
2306.13013v4
1997-11-25
Abundances of Heavy Elements and CO Molecules in High Redshift Damped Lyman-alpha Galaxies
Damped Lyman-alpha systems seen in spectra of background quasars are generally thought to represent high redshift counterparts of present-day galaxies. We summarize observations of heavy element abundances in damped Lyman-alpha systems. The results of a systematic search for CO and C II* absorption in 17 damped Lyman-a...
9711298v1
1997-12-05
Magnetohydrodynamics in the Early Universe and the Damping of Non-linear Alfven Waves
The evolution and viscous damping of cosmic magnetic fields in the early universe, is analysed. Using the fact that the fluid, electromagnetic, and shear viscous energy-momentum tensors are all conformally invariant, the evolution is transformed from the expanding universe setting into that in flat spacetime. Particula...
9712083v1
2001-08-09
Are Simulations of CDM Consistent with Galactic-Scale Observations at High Redshift?
We compare new observations on the kinematic characteristics of the damped Lya systems against results from numerical SPH simulations to test the predictions of hierarchical galaxy formation. This exercise is particularly motivated by recent numerical results on the cross-section of damped Lya systems. Our analysis foc...
0108154v1
2003-03-19
Distinct Abundance Patterns in Multiple Damped Ly-alpha Galaxies: Evidence for Truncated Star Formation?
(abridged) Following our previous work on metal abundances of a double damped Ly-alpha system with a line-of-sight separation ~2000 km/s (Ellison & Lopez 2001), we present VLT UVES abundances of 3 new systems spanning a total of \~6000 km/s at z~2.5 toward the southern QSO CTQ247. These abundances are supplemented with...
0303441v1
2003-05-16
New Damped Lya Metallicities from ESI Spectroscopy of Five Palomar Sky Survey Quasars
This paper presents chemical abundance measurements for 12 new z>3 damped Lya systems discovered toward five quasars from the Palomar Sky Survey. We determine HI column densities from profile fits to the observed damped Lya profiles and measure ionic column densities and limits for all observed metal-line transitions. ...
0305313v1
2006-07-06
Ekman layer damping of r-modes revisited
We investigate the damping of neutron star r-modes due to the presence of a viscous boundary (Ekman) layer at the interface between the crust and the core. Our study is motivated by the possibility that the gravitational-wave driven instability of the inertial r-modes may become active in rapidly spinning neutron stars...
0607105v2
1997-11-05
Hydrodynamic damping in trapped Bose gases
Griffin, Wu and Stringari have derived the hydrodynamic equations of a trapped dilute Bose gas above the Bose-Einstein transition temperature. We give the extension which includes hydrodynamic damping, following the classic work of Uehling and Uhlenbeck based on the Chapman-Enskog procedure. Our final result is a close...
9711036v4
1998-05-01
Finite Temperature Perturbation Theory for a Spatially Inhomogeneous Bose-condensed Gas
We develop a finite temperature perturbation theory (beyond the mean field) for a Bose-condensed gas and calculate temperature-dependent damping rates and energy shifts for Bogolyubov excitations of any energy. The theory is generalized for the case of excitations in a spatially inhomogeneous (trapped) Bose-condensed g...
9805015v2
2002-07-30
Microscopic relaxation mechanisms and linear magnetization dynamics
Linear magnetization dynamics in the presense of a thermal bath is analyzed for two general classes of microscopic damping mechanisms. The resulting stochastic differential equations are always in the form of a damped harmonic oscillator driven by a thermal field. The damping term contains both the interaction mechanis...
0207721v1
2004-03-25
XMCD characterization of rare-earth dopants in Ni$_{81}$Fe$_{19}$(50nm): microscopic basis of engineered damping
We present direct evidence for the contribution of local orbital moments to the damping of magnetization precession in magnetic thin films. Using x-ray magnetic circular dichroism (XMCD) characterization of rare-earth (RE) M$_{4,5}$ edges in Ni$_{81}$Fe$_{19}$ doped with $<$ 2% Gd and Tb, we show that the enhancement o...
0403627v1
2005-02-08
Landau Damping of Spin Waves in Trapped Boltzmann Gases
A semiclassical method is used to study Landau damping of transverse pseudo-spin waves in harmonically trapped ultracold gases in the collisionless Boltzmann limit. In this approach, the time evolution of a spin is calculated numerically as it travels in a classical orbit through a spatially dependent mean field. This ...
0502189v1
2005-06-01
Landau damping of Bogoliubov excitations in optical lattices at finite temperature
We study the damping of Bogoliubov excitations in an optical lattice at finite temperatures. For simplicity, we consider a Bose-Hubbard tight-binding model and limit our analysis to the lowest excitation band. We use the Popov approximation to calculate the temperature dependence of the number of condensate atoms $n^{\...
0506016v1
2006-06-15
Landau damping: instability mechanism of superfluid Bose gases moving in optical lattices
We investigate Landau damping of Bogoliubov excitations in a dilute Bose gas moving in an optical lattice at finite temperatures. Using a 1D tight-binding model, we explicitly obtain the Landau damping rate, the sign of which determines the stability of the condensate. We find that the sign changes at a certain condens...
0606398v2
2006-10-10
Spin-transfer in an open ferromagnetic layer: from negative damping to effective temperature
Spin-transfer is a typical spintronics effect that allows a ferromagnetic layer to be switched by spin-injection. Most of the experimental results about spin transfer are described on the basis of the Landau-Lifshitz-Gilbert equation of the magnetization, in which additional current-dependent damping factors are added,...
0610264v1
1999-09-24
Gauge Invariance of Nonlinear Landau Damping Rate of Bose Excitations in Quark-Gluon Plasma
On the basis of the approximate dynamical equations describing the behavior of quark-gluon plasma (QGP) in the semiclassical limit and Yang-Mills equation, the kinetic equation for longitudinal waves (plasmons) is obtained. With the Ward identities the gauge invariance of obtained nonlinear Landau damping rate is prove...
9909505v1
2005-07-16
Sharp estimates for the number of degrees of freedom for the damped-driven 2D Navier--Stokes equations
We derive upper bounds for the number of asymptotic degrees (determining modes and nodes) of freedom for the two-dimensional Navier--Stokes system and Navier-Stokes system with damping. In the first case we obtain the previously known estimates in an explicit form, which are larger than the fractal dimension of the glo...
0507327v1
2006-12-04
A singular perturbation approach for choosing PageRank damping factor
The choice of the PageRank damping factor is not evident. The Google's choice for the value c=0.85 was a compromise between the true reflection of the Web structure and numerical efficiency. However, the Markov random walk on the original Web Graph does not reflect the importance of the pages because it absorbs in dead...
0612079v1
1998-10-26
Microscopic Structure of Rotational Damping
The damping of collective rotational motion is studied microscopically, making use of shell model calculations based on the cranked Nilsson deformed mean-field and on residual two-body interactions, and focusing on the shape of the gamma-gamma correlation spectra and on its systematic behavior. It is shown that the spe...
9810066v1
2004-07-25
Rotational damping in a multi-$j$ shell particles-rotor model
The damping of collective rotational motion is investigated by means of particles-rotor model in which the angular momentum coupling is treated exactly and the valence nucleons are in a multi-$j$ shell mean-field. It is found that the onset energy of rotational damping is around 1.1 MeV above yrast line, and the number...
0407089v3
2001-07-19
Manifold Damping of Transverse Wakefields in High Phase Advance Traveling Wave Structures and Local Damping of Dipole Wakefields in Standing Wave Accelerators
Operating the SLAC/KEK DDS (Damped Detuned Structure) X-band linacs at high gradients (in excess of 70MV/m) has recently been found to be limited by the accelerator structures breaking down and as a consequence severe damage occurs to the cells which makes the structures inoperable. A series of recent experiments at SL...
0107048v1
2002-06-28
Manifold Damping Of Wakefields In High Phase Advance Linacs For The NLC
Earlier RDDS (Rounded Damped Detuned Structures) [1,2], designed, fabricated and tested at SLAC, in collaboration with KEK, have been shown to damp wakefields successfully. However, electrical breakdown has been found to occur in these structures and this makes them inoperable at the desired gradient. Recent results [3...
0206090v1
2006-06-30
Nonlinear Damping of the LC Circuit using Anti-parallel Diodes
We investigate a simple variation of the series RLC circuit in which anti-parallel diodes replace the resistor. This results in a damped harmonic oscillator with a nonlinear damping term that is maximal at zero current and decreases with an inverse current relation for currents far from zero. A set of nonlinear differe...
0606261v1
1995-11-11
A New Look at the Landau's Theory of Spreading and Damping of Waves in Collisionless Plasmas
The theory of plasma waves and Landau damping in Maxwellian plasmas, Landau's ``rule of pass around poles'' include doubtful statements, particularly related to an artificial ``constructing'' of the dispersion equation, what should allow the possibility of its solution otherwise not existing at all, and the possibility...
9511001v1
2001-07-27
Quantum limits of cold damping with optomechanical coupling
Thermal noise of a mirror can be reduced by cold damping. The displacement is measured with a high-finesse cavity and controlled with the radiation pressure of a modulated light beam. We establish the general quantum limits of noise in cold damping mechanisms and we show that the optomechanical system allows to reach t...
0107138v2
2005-05-20
A symmetric treatment of damped harmonic oscillator in extended phase space
Extended phase space (EPS) formulation of quantum statistical mechanics treats the ordinary phase space coordinates on the same footing and thereby permits the definite the canonical momenta conjugate to these coordinates . The extended lagrangian and extended hamiltonian are defined in EPS by the same procedure as one...
0505147v1
2007-08-28
Pattern formation in the damped Nikolaevskiy equation
The Nikolaevskiy equation has been proposed as a model for seismic waves, electroconvection and weak turbulence; we show that it can also be used to model transverse instabilities of fronts. This equation possesses a large-scale "Goldstone" mode that significantly influences the stability of spatially periodic steady s...
0708.3735v1
2008-01-12
Strong and weak coupling limits in optics of quantum well excitons
A transition between the strong (coherent) and weak (incoherent) coupling limits of resonant interaction between quantum well (QW) excitons and bulk photons is analyzed and quantified as a function of the incoherent damping rate caused by exciton-phonon and exciton-exciton scattering. For confined QW polaritons, a seco...
0801.1895v2
2008-01-22
Damped Bloch Oscillations of Bose-Einstein Condensates in Disordered Potential Gradients
We investigate both experimentally and theoretically disorder induced damping of Bloch oscillations of Bose-Einstein condensates in optical lattices. The spatially inhomogeneous force responsible for the damping is realised by a combination of a disordered optical and a magnetic gradient potential. We show that the inh...
0801.3437v2
2008-02-26
Fractional Langevin Equation: Over-Damped, Under-Damped and Critical Behaviors
The dynamical phase diagram of the fractional Langevin equation is investigated for harmonically bound particle. It is shown that critical exponents mark dynamical transitions in the behavior of the system. Four different critical exponents are found. (i) $\alpha_c=0.402\pm 0.002$ marks a transition to a non-monotonic ...
0802.3777v1
2008-04-26
Vibrational modes of metal nanoshells and bimetallic core-shell nanoparticles
We study theoretically spectrum of radial vibrational modes in composite metal nanostructures such as bimetallic core-shell particles and metal nanoshells with dielectric core in an environment. We calculate frequencies and damping rates of fundamental (breathing) modes for these nanostructures along with those of two ...
0804.4249v2
2008-09-26
Damping of the baryon acoustic oscillations in the matter power spectrum as a probe of the growth factor
We investigate the damping of the baryon acoustic oscillations (BAO) signature in the matter power spectrum due to the quasi-nonlinear clustering of density perturbations. On the basis of the third order perturbation theory, we construct a fitting formula of the damping in an analytic way. This demonstrates that the da...
0809.4538v2
2008-10-07
Corotational Damping of Diskoseismic C-modes in Black Hole Accretion Discs
Diskoseismic c-modes in accretion discs have been invoked to explain low-frequency variabilities observed in black-hole X-ray binaries. These modes are trapped in the inner-most region of the disc and have frequencies much lower than the rotation frequency at the disc inner radius. We show that because the trapped wave...
0810.1299v3
2008-10-10
Non-standard conserved Hamiltonian structures in dissipative/damped systems : Nonlinear generalizations of damped harmonic oscillator
In this paper we point out the existence of a remarkable nonlocal transformation between the damped harmonic oscillator and a modified Emden type nonlinear oscillator equation with linear forcing, $\ddot{x}+\alpha x\dot{x}+\beta x^3+\gamma x=0,$ which preserves the form of the time independent integral, conservative Ha...
0810.1819v2
2008-11-05
R-matrix inner-shell electron-impact excitation of Fe$^{15+}$ including Auger-plus-radiation damping
We present results for the inner-shell electron-impact excitation of Fe$^{15+}$ using the intermediate-coupling frame transformation {\it R}-matrix approach in which Auger-plus-radiation damping has been included. The target and close-coupling expansions are both taken to be the 134 levels belonging to the configuratio...
0811.0750v1
2009-03-11
An alternate design for CLIC main linac wakefield suppression
The present design of the main accelerating structure for CLIC is based on heavy damping (WDS) with a Q of ~10. The wakefield suppression in this case entails locating the damping materials in relatively close proximity to the accelerating cells. Herein we present an alternate design for the main accelerating structure...
0903.1935v1
2009-04-17
Revealing Sub-Surface Vibrational Modes by Atom-Resolved Damping Force Spectroscopy
We propose to use the damping signal of an oscillating cantilever in dynamic atomic force microscopy as a noninvasive tool to study the vibrational structure of the substrate. We present atomically resolved maps of damping in carbon nanotube peapods, capable of identifying the location and packing of enclosed Dy@C82 mo...
0904.2666v1
2009-10-02
Damping of a nanomechanical oscillator strongly coupled to a quantum dot
We present theoretical and experimental results on the mechanical damping of an atomic force microscope cantilever strongly coupled to a self-assembled InAs quantum dot. When the cantilever oscillation amplitude is large, its motion dominates the charge dynamics of the dot which in turn leads to nonlinear, amplitude-de...
0910.0308v1
2010-01-27
The spatial damping of magnetohydrodynamic waves in a flowing partially ionised prominence plasma
Solar prominences are partially ionised plasmas displaying flows and oscillations. These oscillations show time and spatial damping and, commonly, have been explained in terms of magnetohydrodynamic (MHD) waves. We study the spatial damping of linear non-adiabatic MHD waves in a flowing partially ionised plasma, having...
1001.4962v1
2010-02-26
Correlation Effects in the Stochastic Landau-Lifshitz-Gilbert Equation
We analyze the Landau-Lifshitz-Gilbert equation when the precession motion of the magnetic moments is additionally subjected to an uniaxial anisotropy and is driven by a multiplicative coupled stochastic field with a finite correlation time $\tau$. The mean value for the spin wave components offers that the spin-wave d...
1002.4958v1
2010-03-04
Internal dissipation of a polymer
The dynamics of flexible polymer molecules are often assumed to be governed by hydrodynamics of the solvent. However there is considerable evidence that internal dissipation of a polymer contributes as well. Here we investigate the dynamics of a single chain in the absence of solvent to characterize the nature of this ...
1003.0944v2
2010-05-26
Indirect Evidence for Lévy Walks in Squeeze Film Damping
Molecular flow gas damping of mechanical motion in confined geometries, and its associated noise, is important in a variety of fields, including precision measurement, gravitational wave detection, and MEMS devices. We used two torsion balance instruments to measure the strength and distance-dependence of `squeeze film...
1005.4926v2
2010-05-28
Gravitational wave asteroseismology with fast rotating neutron stars
We investigate damping and growth times of the f-mode for rapidly rotating stars and a variety of different polytropic equations of state in the Cowling approximation. We discuss the differences in the eigenfunctions of co- and counterrotating modes and compute the damping times of the f-mode for several EoS and all ro...
1005.5228v3
2010-06-09
Synchrotron oscillation damping due to beam-beam collisions
In DA{\Phi}NE, the Frascati e+/e- collider, the crab waist collision scheme has been successfully implemented in 2008 and 2009. During the collision operations for Siddharta experiment, an unusual synchrotron damping effect has been observed. Indeed, with the longitudinal feedback switched off, the positron beam become...
1006.1783v1
2010-06-30
Landau Damping of Baryon Structure Formation in the Post Reionization Epoch
It has been suggested by Chen and Lai that the proper description of the large scale structure formation of the universe in the post-reionization era, which is conventionally characterized via gas hydrodynamics, should include the plasma collective effects in the formulation. Specifically, it is the combined pressure f...
1006.5777v1
2010-07-12
Passive damping of beam vibrations through distributed electric networks and piezoelectric transducers: prototype design and experimental validation
The aim of this work is two-fold: to design devices for passive electric damping of structural vibrations by distributed piezoelectric transducers and electric networks, and to experimentally validate the effectiveness of such a damping concept. Two different electric networks are employed, namely a purely resistive ne...
1007.1863v1
2010-07-23
Highly-damped quasi-normal frequencies for piecewise Eckart potentials
Highly-damped quasi-normal frequencies are very often of the form omega_n = (offset) + i n (gap). We investigate the genericity of this phenomenon by considering a model potential that is piecewise Eckart (piecewise Poeschl-Teller), and developing an analytic "quantization condition" for the highly-damped quasi-normal ...
1007.4039v2
2010-09-23
Asymptotic Spectrum of Kerr Black Holes in the Small Angular Momentum Limit
We study analytically the highly damped quasinormal modes of Kerr black holes in the small angular momentum limit. To check the previous analytic calculations in the literature, which use a combination of radial and tortoise coordinates, we reproduce all the results using the radial coordinate only. According to the ea...
1009.4632v2
2010-12-31
Exact Tkachenko modes and their damping in the vortex lattice regime of rapidly rotating bosons
We have found an exact analytical solution of the Bogoliubov-de Gennes equations for the Tkachenko modes of the vortex lattice in the lowest Landau level (LLL) in the thermodynamic limit at any momenta and calculated their damping rates. At finite temperatures both Beliaev and Landau damping leads to momentum independe...
1101.0269v1
2011-01-20
Decoherence and entanglement degradation of a qubit-qutrit system in non-inertial frames
We study the effect of decoherence on a qubit-qutrit system under the influence of global, local and multilocal decoherence in non-inertial frames. We show that the entanglement sudden death can be avoided in non-inertial frames in the presence of amplitude damping, depolarizing and phase damping channels. However, deg...
1101.3986v1
2011-07-17
Nonlinear-damping continuation of the nonlinear Schrödinger equation - a numerical study
We study the nonlinear-damping continuation of singular solutions of the critical and supercritical NLS. Our simulations suggest that for generic initial conditions that lead to collapse in the undamped NLS, the solution of the weakly-damped NLS $$ i\psi_t(t,\X)+\Delta\psi+|\psi|^{p-1}\psi+i\delta|\psi|^{q-1}\psi=0,\qq...
1107.3281v1
2011-10-05
Radiation damping in pulsed Gaussian beams
We consider the effects of radiation damping on the electron dynamics in a Gaussian beam model of a laser field. For high intensities, i.e. with dimensionless intensity a0 \gg 1, it is found that the dynamics divide into three regimes. For low energy electrons (low initial {\gamma}-factor, {\gamma}0) the radiation damp...
1110.0996v1
2012-03-28
Analysis of the absorbing layers for the weakly-compressible lattice Boltzmann schemes
It has been demonstrated that Lattice Boltzmann schemes (LBSs) are very efficient for Computational AeroAcoustics (CAA). In order to handle the issue of absorbing acoustic boundary conditions for LBS, three kinds of damping terms are proposed and added into the right hand sides of the governing equations of LBS. From t...
1203.6350v1
2012-04-11
Formation of bremsstrahlung in an absorptive QED/QCD medium
The radiative energy loss of a relativistic charge in a dense, absorptive medium can be affected significantly by damping phenomena. The effect is more pronounced for large energies of the charge and/or large damping of the radiation. This can be understood in terms of a competition between the formation time of bremss...
1204.2469v2
2012-06-05
Existence and exponential stability of a damped wave equation with dynamic boundary conditions and a delay term
In this paper we consider a multi-dimensional wave equation with dynamic boundary conditions related to the Kelvin-Voigt damping and a delay term acting on the boundary. If the weight of the delay term in the feedback is less than the weight of the term without delay or if it is greater under an assumption between the ...
1206.1010v1
2012-08-27
Analysis of the damped quantum search and its application to the one-dimensional Ising system
An analysis on the damped quantum search by exploring the rate at which the target state is obtained. The results were compared with that of the classical search since the standard Grover's algorithm does not give a convergent result if the number of target state is unknown. For a large number of target states, the cla...
1208.5509v1
2012-11-11
Dissipation in relativistic superfluid neutron stars
We analyze damping of oscillations of general relativistic superfluid neutron stars. To this aim we extend the method of decoupling of superfluid and normal oscillation modes first suggested in [Gusakov & Kantor PRD 83, 081304(R) (2011)]. All calculations are made self-consistently within the finite temperature superfl...
1211.2452v1
2013-03-07
Universal damping behavior of dipole oscillations of one-dimensional ultracold gases induced by quantum phase slips
We study superflow decay via quantum phase slips in trapped one-dimensional (1D) quantum gases through dipole oscillations induced by sudden displacement of the trapping potential. We find the relation between the damping rate of the dipole oscillation $G$ and the phase-slip nucleation rate $\Gamma$ as $G\propto \Gamma...
1303.1616v1
2013-07-16
Blow-up of solutions to the one-dimensional semilinear wave equation with damping depending on time and space variables
In this paper, we give a small data blow-up result for the one-dimensional semilinear wave equation with damping depending on time and space variables. We show that if the damping term can be regarded as perturbation, that is, non-effective damping in a certain sense, then the solution blows up in finite time for any p...
1307.4260v2
2013-11-12
Landau damping: paraproducts and Gevrey regularity
We give a new, simpler, proof of nonlinear Landau damping on T^d in Gevrey-1/s regularity (s > 1/3) which matches the regularity requirement predicted by the formal analysis of Mouhot and Villani in the original proof of Landau damping [Acta Mathematica 2011]. Our proof combines in a novel way ideas from the original p...
1311.2870v1
2014-02-07
One-dimensional random attractor and rotation number of the stochastic damped sine-Gordon equation
This paper is devoted to the study of the asymptotic dynamics of the stochastic damped sine-Gordon equation with homogeneous Neumann boundary condition. It is shown that for any positive damping and diffusion coefficients, the equation possesses a random attractor, and when the damping and diffusion coefficients are su...
1402.1787v1
2014-02-26
Comparison of methods for numerical calculation of continuum damping
Continuum resonance damping is an important factor in determining the stability of certain global modes in fusion plasmas. A number of analytic and numerical approaches have been developed to compute this damping, particularly in the case of the toroidicity-induced shear Alfv\'en eigenmode. This paper compares results ...
1402.6389v1
2014-05-09
Magnetization dynamics and damping due to electron-phonon scattering in a ferrimagnetic exchange model
We present a microscopic calculation of magnetization damping for a magnetic "toy model." The magnetic system consists of itinerant carriers coupled antiferromagnetically to a dispersionless band of localized spins, and the magnetization damping is due to coupling of the itinerant carriers to a phonon bath in the prese...
1405.2347v1
2014-05-16
Quantum corrections to nonlinear ion acoustic wave with Landau damping
Quantum corrections to nonlinear ion acoustic wave with Landau damping have been computed using Wigner equation approach. The dynamical equation governing the time development of nonlinear ion acoustic wave with semiclassical quantum corrections is shown to have the form of higher KdV equation which has higher order no...
1405.4107v1
2014-05-19
Mesh Size and Damped Edge Effects in Micromagnetic Spin Wave Simulation
We have studied the dependence of spin wave dispersion on the characteristics of the mesh used in a finite element micromagnetic simulation. It is shown that the dispersion curve has a cut off at a frequency which is analytically predictable. The frequency depends on the average mesh length used for the simulation. Bas...
1405.4615v2
2014-07-08
Fourier-Hermite spectral representation for the Vlasov-Poisson system in the weakly collisional limit
We study Landau damping in the 1+1D Vlasov-Poisson system using a Fourier-Hermite spectral representation. We describe the propagation of free energy in phase space using forwards and backwards propagating Hermite modes recently developed for gyrokinetics [Schekochihin et al. (2014)]. The change in the electric field c...
1407.1932v1
2014-08-14
Particle Dynamics in Damped Nonlinear Quadrupole Ion Traps
We examine the motions of particles in quadrupole ion traps as a function of damping and trapping forces, including cases where nonlinear damping or nonlinearities in the electric field geometry play significant roles. In the absence of nonlinearities, particles are either damped to the trap center or ejected, while th...
1409.6262v1
2015-01-03
Finite-Parameters Feedback Control for Stabilizing Damped Nonlinear Wave Equations
In this paper we introduce a finite-parameters feedback control algorithm for stabilizing solutions of various classes of damped nonlinear wave equations. Specifically, stabilization the zero steady state solution of initial boundary value problems for nonlinear weakly and strongly damped wave equations, nonlinear wave...
1501.00556v1
2015-06-26
A Universal Damping Mechanism of Quantum Vibrations in Deep Sub-Barrier Fusion Reactions
We demonstrate the damping of quantum octupole vibrations near the touching point when two colliding nuclei approach each other in the mass-asymmetric $^{208}$Pb + $^{16}$O system, for which the strong fusion hindrance was clearly observed. We, for the first time, apply the random-phase approximation method to the heav...
1506.07963v1
2015-07-28
Phenomenology of chiral damping in noncentrosymmetric magnets
A phenomenology of magnetic chiral damping is proposed in the context of magnetic materials lacking inversion symmetry breaking. We show that the magnetic damping tensor adopts a general form that accounts for a component linear in magnetization gradient in the form of Lifshitz invariants. We propose different microsco...
1507.07762v1
2015-08-06
Phenomenological description of the nonlocal magnetization relaxation in magnonics, spintronics, and domain-wall dynamics
A phenomenological equation called Landau-Lifshitz-Baryakhtar (LLBar) equation, which could be viewed as the combination of Landau-Lifshitz (LL) equation and an extra "exchange damping" term, was derived by Baryakhtar using Onsager's relations. We interpret the origin of this "exchange damping" as nonlocal damping by l...
1508.01478v1
2016-01-05
Vlasov Simulations of Electron-Ion Collision Effects on Damping of Electron Plasma Waves
Collisional effects can play an essential role in the dynamics of plasma waves by setting a minimum damping rate and by interfering with wave-particle resonances. Kinetic simulations of the effects of electron-ion pitch angle scattering on Electron Plasma Waves (EPWs) are presented here. In particular, the effects of s...
1601.01002v1
2016-02-13
The effect of orbital damping during planet migration on the Inclination and Eccentricity Distributions of Neptune Trojans
We explore planetary migration scenarios for formation of high inclination Neptune Trojans (NTs) and how they are affected by the planetary migration of Neptune and Uranus. If Neptune and Uranus's eccentricity and inclination were damped during planetary migration, then their eccentricities and inclinations were higher...
1602.04303v1
2016-03-08
Damping of the Higgs and Nambu-Goldstone modes of superfluid Bose gases at finite temperatures
We study collective modes of superfluid Bose gases in optical lattices at commensurate fillings. We focus on the vicinity of the quantum phase transition to the Mott insulator, where there exists the Higgs amplitude mode in addition to the Nambu-Goldstone phase mode associated with the spontaneous U(1) symmetry breakin...
1603.02395v1
2016-04-12
Offline software for the DAMPE experiment
A software system has been developed for the DArk Matter Particle Explorer (DAMPE) mission, a satellite-based experiment. The DAMPE software is mainly written in C++ and steered using Python script. This article presents an overview of the DAMPE offline software, including the major architecture design and specific imp...
1604.03219v6
2016-04-18
Stabilization of Damped Waves on Spheres and Zoll Surfaces of Revolution
We study the strong stabilization of wave equations on some sphere-like manifolds, with rough damping terms which do not satisfy the geometric control condition posed by Rauch-Taylor and Bardos-Lebeau-Rauch. We begin with an unpublished result of G. Lebeau, which states that on S^d , the indicator function of the upper...
1604.05218v2
2016-07-25
Damping of parametrically excited magnons in the presence of the longitudinal spin Seebeck effect
The impact of the longitudinal spin Seebeck effect (LSSE) on the magnon damping in magnetic-insulator/nonmagnetic-metal bilayers was recently discussed in several reports. However, results of those experiments can be blurred by multimode excitation within the measured linewidth. In order to avoid possible intermodal in...
1607.07274v1
2016-07-27
Frequency dispersion of small-amplitude capillary waves in viscous fluids
This work presents a detailed study of the dispersion of capillary waves with small amplitude in viscous fluids using an analytically derived solution to the initial value problem of a small-amplitude capillary wave as well as direct numerical simulation. A rational parametrization for the dispersion of capillary waves...
1607.08266v1
2016-10-18
On the stability of the Bresse system with frictional damping
In this paper, we consider the Bresse system with frictional damping terms and prove some optimal decay results for the $L^2$-norm of the solution and its higher order derivatives. In fact, if we consider just one damping term acting on the second equation of the solution, we show that the solution does not decay at al...
1610.05500v2
2017-02-17
Transition of multi-diffusive states in a biased periodic potential
We study a frequency-dependent damping model of hyper-diffusion within the generalized Langevin equation. The model allows for the colored noise defined by its spectral density, assumed to be proportional to $\omega^{\delta-1}$ at low frequencies with $0<\delta<1$ (sub-Ohmic damping) or $1<\delta<2$ (super-Ohmic dampin...
1702.05370v1
2017-05-21
Dynamical depinning of chiral domain walls
The domain wall depinning field represents the minimum magnetic field needed to move a domain wall, typically pinned by samples' disorder or patterned constrictions. Conventionally, such field is considered independent on the Gilbert damping since it is assumed to be the field at which the Zeeman energy equals the pinn...
1705.07489v2
2017-09-27
Wave turbulence in vibrating plates : the effect of damping
The effect of damping in the wave turbulence regime for thin vibrating plates is studied. An experimental method, allowing measurements of dissipation in the system at all scales, is first introduced. Practical experimental devices for increasing the dissipation are used. The main observable consequence of increasing t...
1709.09438v1
2017-11-02
Vibration Damping of Carbon Nanotube Assembly Materials
Vibration reduction is of great importance in various engineering applications, and a material that exhibits good vibration damping along with high strength and modulus has become more and more vital. Owing to the superior mechanical property of carbon nanotube (CNT), new types of vibration damping material can be deve...
1711.00623v1
2017-12-05
Dark Matter Annihilation from Nearby Ultra-compact Micro Halos to Explain the Tentative Excess at ~1.4 TeV in DAMPE data
The tentative 1.4 TeV excess in the $e^+e^-$ spectrum measured by The DArk Matter Particle Explorer (DAMPE) motivates the possible existence of one or more local dark matter concentrated regions. In particular, Ultra-compact Micro Halos (UCMHs) seeded by large density perturbations in the early universe, allocated with...
1712.01724v2
2017-12-21
A new charge reconstruction algorithm for the DAMPE silicon microstrip detector
The DArk Matter Particle Explorer (DAMPE) is one of the four satellites within the Strategic Pioneer Research Program in Space Science of the Chinese Academy of Science (CAS). The Silicon-Tungsten Tracker (STK), which is composed of 768 singled-sided silicon microstrip detectors, is one of the four subdetectors in DAMP...
1712.08011v1
2018-01-23
The dominancy of damping like torque for the current induced magnetization switching in Pt/Co/W multilayers
Two classes of spin-orbit coupling (SOC) mechanisms have been considered as candidate sources for the spin orbit torque (SOT): the spin Hall Effect (SHE) in heavy metals with strong SOC and the Rashba effect arising from broken inversion symmetry at material surfaces and interfaces. In this work, we have investigated t...
1801.07408v1
2018-02-20
The damped wave equation with unbounded damping
We analyze new phenomena arising in linear damped wave equations on unbounded domains when the damping is allowed to become unbounded at infinity. We prove the generation of a contraction semigroup, study the relation between the spectra of the semigroup generator and the associated quadratic operator function, the con...
1802.07026v1
2018-04-06
Exponential Integrators Preserving Local Conservation Laws of PDEs with Time-Dependent Damping/Driving Forces
Structure-preserving algorithms for solving conservative PDEs with added linear dissipation are generalized to systems with time-dependent damping/driving terms. This study is motivated by several PDE models of physical phenomena, such as Korteweg-de Vries, Klein-Gordon, Schr\"{o}dinger, and Camassa-Holm equations, all...
1804.02266v1
2018-05-29
Enhancing precision of damping rate by PT symmetric Hamiltonian
We utilize quantum Fisher information to investigate the damping parameter precision of a dissipative qubit. PT symmetric non-Hermitian Hamiltonian is used to enhance the parameter precision in two models: one is direct PT symmetric quantum feedback; the other is that the damping rate is encoded into a effective PT sym...
1805.11216v1
2018-05-31
Damping Effect on PageRank Distribution
This work extends the personalized PageRank model invented by Brin and Page to a family of PageRank models with various damping schemes. The goal with increased model variety is to capture or recognize a larger number of types of network activities, phenomena and propagation patterns. The response in PageRank distribut...
1806.00127v1
2018-07-13
Gilbert damping of high anisotropy Co/Pt multilayers
Using broadband ferromagnetic resonance, we measure the damping parameter of [Co(5 \r{A})/Pt(3 \r{A})]${\times 6}$ multilayers whose growth was optimized to maximize the perpendicular anisotropy. Structural characterizations indicate abrupt interfaces essentially free of intermixing despite the miscible character of Co...
1807.04977v1
2018-08-10
Relativistic charge solitons created due to nonlinear Landau damping: A candidate for explaining coherent radio emission in pulsars
A potential resolution for the generation of coherent radio emission in pulsar plasma is the existence of relativistic charge solitons, which are solutions of nonlinear Schr\"{o}dinger equation (NLSE). In an earlier study, Melikidze et al. (2000) investigated the nature of these charge solitons; however, their analysis...
1808.03657v1
2018-08-13
Gilbert damping phenomenology for two-sublattice magnets
We present a systematic phenomenological description of Gilbert damping in two-sublattice magnets. Our theory covers the full range of materials from ferro- via ferri- to antiferromagnets. Following a Rayleigh dissipation functional approach within a Lagrangian classical field formulation, the theory captures intra- as...
1808.04385v2
2018-11-21
Super Damping of Mechanical Vibrations
We report the phenomenon of coherent super decay, where a linear sum of several damped oscillators can collectively decay much faster than the individual ones in the first stage, followed by stagnating ones after more than 90 percent of the energy has already been dissipated. The parameters of the damped oscillators fo...
1811.08621v2
2018-11-29
Flowing fibers as a proxy of turbulence statistics
The flapping states of a flexible fiber fully coupled to a three-dimensional turbulent flow are investigated via state-of-the-art numerical methods. Two distinct flapping regimes are predicted by the phenomenological theory recently proposed by Rosti et al. [Phys. Rev. Lett. 121, 044501, 2018]: the under-damped regime,...
1811.12023v2
2018-11-26
Linear Theory of Electron-Plasma Waves at Arbitrary Collisionality
The dynamics of electron-plasma waves are described at arbitrary collisionality by considering the full Coulomb collision operator. The description is based on a Hermite-Laguerre decomposition of the velocity dependence of the electron distribution function. The damping rate, frequency, and eigenmode spectrum of electr...
1811.12855v2
2019-01-07
Giant anisotropy of Gilbert damping in epitaxial CoFe films
Tailoring Gilbert damping of metallic ferromagnetic thin films is one of the central interests in spintronics applications. Here we report a giant Gilbert damping anisotropy in epitaxial Co$_{50}$Fe$_{50}$ thin film with a maximum-minimum damping ratio of 400 \%, determined by broadband spin-torque as well as inductive...
1901.01941v1