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2019-01-17
Influences of interfacial oxidization on surface magnetic energy, magnetic damping and spin-orbit-torques in Pt / ferromagnet / capping structures
We investigate the effect of capping layer (CAP) on the interfacial magnetic anisotropy energy density (K_S), magnetic damping ({\alpha}), and spin-orbit torques (SOTs) in heavy-metal (Pt) / ferromagnet (Co or Py) / CAP (MgO/Ta, HfOx, or TaN). At room temperature (RT) the CAP materials influence the effective magnitude...
1901.05777v1
2019-05-31
The amplitude of solar p-mode oscillations from three-dimensional convection simulations
The amplitude of solar p-mode oscillations is governed by stochastic excitation and mode damping, both of which take place in the surface convection zone. However, the time-dependent, turbulent nature of convection makes it difficult to self-consistently study excitation and damping processes through the use of traditi...
1905.13397v2
2019-08-23
Damping enhancement in coherent ferrite/insulating-paramagnet bilayers
High-quality epitaxial ferrites, such as low-damping MgAl-ferrite (MAFO), are promising nanoscale building blocks for all-oxide heterostructures driven by pure spin current. However, the impact of oxide interfaces on spin dynamics in such heterostructures remains an open question. Here, we investigate the spin dynamics...
1908.08629v2
2019-10-03
Many-body collision contributions to electron momentum damping rates in a plasma influenced by electron strong coupling
Experimental studies of electron-ion collision rates in an ultracold neutral plasma (UNP) can be conducted through measuring the rate of electron plasma oscillation damping. For sufficiently cold and dense conditions where strong coupling influences are important, the measured damping rate was faster by 37\% than theor...
1910.01707v1
2019-10-18
Escape of a forced-damped particle from weakly nonlinear truncated potential well
Escape from a potential well is an extreme example of transient behavior. We consider the escape of the harmonically forced particle under viscous damping from the benchmark truncated weakly nonlinear potential well. Main attention is paid to most interesting case of primary 1:1 resonance. The treatment is based on mul...
1910.08545v1
2019-10-24
Topological damping Rashba spin orbit torque in ballistic magnetic domain walls
Rashba spin orbit torque derived from the broken inversion symmetry at ferromagnet/heavy metal interfaces has potential application in spintronic devices. In conventional description of the precessional and damping components of the Rashba spin orbit torque in magnetization textures, the decomposition coefficients are ...
1910.10977v2
2019-11-02
Tuning Non-Gilbert-type damping in FeGa films on MgO(001) via oblique deposition
The ability to tailor the damping factor is essential for spintronic and spin-torque applications. Here, we report an approach to manipulate the damping factor of FeGa/MgO(001) films by oblique deposition. Owing to the defects at the surface or interface in thin films, two-magnon scattering (TMS) acts as a non-Gilbert ...
1911.00728v1
2019-11-13
Dipole oscillations of fermionic superfluids along the BEC-BCS crossover in disordered potentials
We investigate dipole oscillations of ultracold Fermi gases along the BEC-BCS crossover through disordered potentials. We observe a disorder-induced damping of oscillations as well as a change of the fundamental Kohn-mode frequency. The measurement results are compared to numerical density matrix renormalization group ...
1911.05638v1
2020-02-07
Model of damping and anisotropy at elevated temperatures: application to granular FePt films
Understanding the damping mechanism in finite size systems and its dependence on temperature is a critical step in the development of magnetic nanotechnologies. In this work, nano-sized materials are modeled via atomistic spin dynamics, the damping parameter being extracted from Ferromagnetic Resonance (FMR) simulation...
2002.02865v1
2020-04-06
Damping-like Torque in Monolayer 1T-TaS$_2$
A damping-like spin orbit torque (SOT) is a prerequisite for ultralow power spin logic devices. Here, we report on the damping-like SOT in just one monolayer of the conducting transition metal dichalcogenide (TMD) TaS$_2$ interfaced with a NiFe (Py) ferromagnetic layer. The charge-spin conversion efficiency is found to...
2004.02649v1
2020-05-15
Calibration and performance of the neutron detector onboard of the DAMPE mission
The DArk Matter Particle Explorer (DAMPE), one of the four space-based scientific missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, has been successfully launched on Dec. 17th 2015 from Jiuquan launch center. One of the most important scientific goals of...
2005.07828v1
2020-05-16
Simultaneous observation of anti-damping and inverse spin Hall effect in La$_{0.67}$Sr$_{0.33}$MnO$_{3}$/Pt bilayer system
Manganites have shown potential in spintronics because they exhibit high spin polarization. Here, by ferromagnetic resonance we have studied the damping properties of La$_{0.67}$Sr$_{0.33}$MnO$_{3}$/Pt bilayers which are prepared by oxide molecular beam epitaxy. The damping coefficient ($\alpha$) of La$_{0.67}$Sr$_{0.3...
2005.07848v3
2020-07-25
Using a Lindbladian approach to model decoherence in two coupled nuclear spins via correlated phase-damping and amplitude damping noise channels
In this work, we studied the relaxation dynamics of coherences of different order present in a system of two coupled nuclear spins. We used a previously designed model for intrinsic noise present in such systems which considers the Lindblad master equation for Markovian relaxation. We experimentally created zero-, sing...
2007.12972v1
2020-09-29
The effects of nonlinear damping on degenerate parametric amplification
This paper considers the dynamic response of a single degree of freedom system with nonlinear stiffness and nonlinear damping that is subjected to both resonant direct excitation and resonant parametric excitation, with a general phase between the two. This generalizes and expands on previous studies of nonlinear effec...
2009.14284v2
2020-11-10
Damped oscillators within the general theory of Casimir and van der Waals forces
It is demonstrated that the general theory of Casimir and van der Waals forces describes the interaction-induced equilibrium thermodynamic potentials of the damped harmonic oscillator bilinearly coupled to the environment. An extended model for a damped oscillator is suggested along the lines of the general theory of C...
2011.04960v2
2021-01-03
The effect of flow on resonant absorption of slow MHD waves in magnetic flux tubes
In this paper, we study kink and sausage oscillations in the presence of longitudinal background flow. We study resonant absorption of the kink and sausage modes in the slow continuum under magnetic pore conditions in the presence of flow. we determine the dispersion relation then solve it numerically, and find the fre...
2101.02064v1
2021-02-01
Blow-up and lifespan estimates for a damped wave equation in the Einstein-de Sitter spacetime with nonlinearity of derivative type
In this article, we investigate the blow-up for local solutions to a semilinear wave equation in the generalized Einstein - de Sitter spacetime with nonlinearity of derivative type. More precisely, we consider a semilinear damped wave equation with a time-dependent and not summable speed of propagation and with a time-...
2102.01137v2
2021-02-02
Analysis of Lower Hybrid Drift Waves in Kappa Distributions over Solar Atmosphere
Kappa distributions and with loss cone features have been frequently observed with flares emissions with the signatures of Lower hybrid waves. We have analysed the plasma with Kappa distributions and with loss cone features for the drift wave instabilities in perpendicular propagation for Large flare and Normal flare a...
2102.01323v1
2021-02-25
Regularity and stability of the semigroup associated with some interacting elastic systems I: A degenerate damping case
In this paper, we examine regularity and stability issues for two damped abstract elastic systems. The damping involves the average velocity and a fractional power $\theta$, with $\theta$ in $[-1,1]$, of the principal operator. The matrix operator defining the damping mechanism for the coupled system is degenerate. Fir...
2102.13217v4
2021-03-05
Existence and congruence of global attractors for damped and forced integrable and nonintegrable discrete nonlinear Schrödinger equations
We study two damped and forced discrete nonlinear Schr\"odinger equations on the one-dimensional infinite lattice. Without damping and forcing they are represented by the integrable Ablowitz-Ladik equation (AL) featuring non-local cubic nonlinear terms, and its standard (nonintegrable) counterpart with local cubic nonl...
2103.03533v1
2021-05-17
Dissipation of Oscillation Energy and Distribution of Damping Power in a Multimachine Power System: A Small-signal Analysis
This paper revisits the concept of damping torque in a multimachine power system and its relation to the dissipation of oscillation energy in synchronous machine windings. As a multimachine extension of an existing result on a single-machine-infinite-bus (SMIB) system, we show that the total damping power for a mode st...
2105.07618v2
2021-06-04
Imaging spin-wave damping underneath metals using electron spins in diamond
Spin waves in magnetic insulators are low-damping signal carriers that could enable a new generation of spintronic devices. The excitation, control, and detection of spin waves by metal electrodes is crucial for interfacing these devices to electrical circuits. It is therefore important to understand metal-induced damp...
2106.02508v2
2021-06-04
Inherent Non-Linear Damping in Resonators with Inertia Amplification
Inertia amplification is a mechanism coupling degrees of freedom within a vibrating structure. Its goal is to achieve an apparent high dynamic mass and, accordingly, a low resonance frequency. Such structures have been described for use in locally resonant metamaterials and phononic crystals to lower the starting frequ...
2106.02576v2
2021-06-30
On the effect of perturbations in first-order optimization methods with inertia and Hessian driven damping
Second-order continuous-time dissipative dynamical systems with viscous and Hessian driven damping have inspired effective first-order algorithms for solving convex optimization problems. While preserving the fast convergence properties of the Nesterov-type acceleration, the Hessian driven damping makes it possible to ...
2106.16159v2
2021-07-02
Anomalous Gilbert Damping and Duffing Features of the SFS {\boldmath $\varphi_0$} Josephson Junction
We demonstrate unusual features of phase dynamics, IV-characteristics and magnetization dynamics of the $\varphi_0$ Josephson junction at small values of spin-orbit interaction, ratio of Josephson to magnetic energy and Gilbert damping. In particular, an anomalous shift of the ferromagnetic resonance frequency with an ...
2107.00982v3
2021-07-13
A new approach to the quantization of the damped harmonic oscillator
In this paper, a new approach for constructing Lagrangians for driven and undriven linearly damped systems is proposed, by introducing a redefined time coordinate and an associated coordinate transformation to ensure that the resulting Lagrangian satisfies the Helmholtz conditions. The approach is applied to canonicall...
2107.05827v3
2021-10-26
Theory of sound attenuation in amorphous solids from nonaffine motions
We present a theoretical derivation of acoustic phonon damping in amorphous solids based on the nonaffine response formalism for the viscoelasticity of amorphous solids. The analytical theory takes into account the nonaffine displacements in transverse waves and is able to predict both the ubiquitous low-energy diffusi...
2110.13446v2
2021-11-21
Energy Transport in 1-Dimensional Oscillator Arrays With Hysteretic Damping
Energy transport in 1-dimensional oscillator arrays has been extensively studied to date in the conservative case, as well as under weak viscous damping. When driven at one end by a sinusoidal force, such arrays are known to exhibit the phenomenon of supratransmission, i.e. a sudden energy surge above a critical drivin...
2111.10816v3
2021-12-15
An Innovative Transverse Emittance Cooling Technique using a Laser-Plasma Wiggler
We propose an innovative beam cooling scheme based on laser driven plasma wakefields to address the challenge of high luminosity generation for a future linear collider. For linear colliders, beam cooling is realised by means of damping rings equipped with wiggler magnets and accelerating cavities. This scheme ensures ...
2112.08163v1
2021-12-21
ISS-Based Robustness to Various Neglected Damping Mechanisms for the 1-D Wave PDE
This paper is devoted to the study of the robustness properties of the 1-D wave equation for an elastic vibrating string under four different damping mechanisms that are usually neglected in the study of the wave equation: (i) friction with the surrounding medium of the string (or viscous damping), (ii) thermoelastic p...
2112.11287v1
2022-01-20
Derivation of the linear Boltzmann equation from the damped quantum Lorentz gas with a general scatterer configuration
It is a fundamental problem in mathematical physics to derive macroscopic transport equations from microscopic models. In this paper we derive the linear Boltzmann equation in the low-density limit of a damped quantum Lorentz gas for a large class of deterministic and random scatterer configurations. Previously this re...
2201.08229v2
2022-01-22
Effect of MagneticField on the Damping Behavior of a Ferrofluid based Damper
This paper is an extension of our earlier work where we had reported a proof of concept for a ferrofluid based damper. The damper used ferrofluid as damping medium and it was seen that damping efficiency of the damper changes on application of magnetic field. The present paper deals with a systematic study of the effec...
2201.09027v1
2022-01-28
Machine learning-based method of calorimeter saturation correction for helium flux analysis with DAMPE experiment
DAMPE is a space-borne experiment for the measurement of the cosmic-ray fluxes at energies up to around 100 TeV per nucleon. At energies above several tens of TeV, the electronics of DAMPE calorimeter would saturate, leaving certain bars with no energy recorded. In the present work we discuss the application of machine...
2201.12185v3
2022-03-10
Accelerated gradient methods combining Tikhonov regularization with geometric damping driven by the Hessian
In a Hilbert setting, for convex differentiable optimization, we consider accelerated gradient dynamics combining Tikhonov regularization with Hessian-driven damping. The Tikhonov regularization parameter is assumed to tend to zero as time tends to infinity, which preserves equilibria. The presence of the Tikhonov regu...
2203.05457v2
2022-04-01
On the Importance of High-Frequency Damping in High-Order Conservative Finite-Difference Schemes for Viscous Fluxes
This paper discusses the importance of high-frequency damping in high-order conservative finite-difference schemes for viscous terms in the Navier-Stokes equations. Investigating nonlinear instability encountered in a high-resolution viscous shock-tube simulation, we have discovered that a modification to the viscous s...
2204.00393v1
2022-06-20
Stability and Damping in the Disks of Massive Galaxies
After their initial formation, disk galaxies are observed to be rotationally stable over periods of >6 Gyr, implying that any large velocity disturbances of stars and gas clouds are damped rapidly on the timescale of their rotation. However, it is also known that despite this damping, there must be a degree of random l...
2206.09671v2
2022-08-25
The Effect of Frequency Droop Damping on System Parameters and Battery Sizing During Load Change Condition
Inverter-based resources (IBR) have been widely studied for their advantages on the current power systems. This increase in the penetration of renewable energy has raised some concerns about the stability of the existing grid. Historically, power systems are dominated by synchronous generators that can easily react to ...
2208.12291v1
2022-09-15
Superfluid $^4$He as a rigorous test bench for different damping models in nanoelectromechanical resonators
We have used nanoelectromechanical resonators to probe superfluid $^4$He at different temperature regimes, spanning over four orders of magnitude in damping. These regimes are characterized by the mechanisms which provide the dominant contributions to damping and the shift of the resonance frequency: tunneling two leve...
2209.07229v2
2022-10-16
Magnetic damping anisotropy in the two-dimensional van der Waals material Fe$_3$GeTe$_2$ from first principles
Magnetization relaxation in the two-dimensional itinerant ferromagnetic van der Waals material Fe$_3$GeTe$_2$, below the Curie temperature, is fundamentally important for applications to low-dimensional spintronics devices. We use first-principles scattering theory to calculate the temperature-dependent Gilbert damping...
2210.08429v1
2022-11-08
On the injection scale of the turbulence in the partially ionized very local interstellar medium
The cascade of magnetohydrodynamic (MHD) turbulence is subject to ion-neutral collisional damping and neutral viscous damping in the partially ionized interstellar medium. By examining the damping effects in the warm and partially ionized local interstellar medium, we find that the interstellar turbulence is damped by ...
2211.04496v1
2022-12-11
The overtone level spacing of a black hole quasinormal frequencies: a fingerprint of a local $SL(2,\mathbb{R})$ symmetry
The imaginary part of the quasinormal frequencies spectrum for a static and spherically symmetric black hole is analytically known to be equally spaced, both for the highly damped and the weakly damped families of quasinormal modes. Some interesting attempts have been made in the last twenty years to understand in simp...
2212.05538v1
2022-12-15
Formation of shifted shock for the 3D compressible Euler equations with time-dependent damping
In this paper, we show the shock formation to the compressible Euler equations with time-dependent damping $\frac{a\p u}{(1+t)^{\lam}}$ in three spatial dimensions without any symmetry conditions. It's well-known that for $\lam>1$, the damping is too weak to prevent the shock formation for suitably large data. However,...
2212.07828v1
2023-01-15
Damped-driven system of bouncing droplets leading to deterministic diffusive behavior
Damped-driven systems are ubiquitous in science, however the damping and driving mechanisms are often quite convoluted. This manuscript presents an experimental and theoretical investigation of a fluidic droplet on a vertically vibrating fluid bath as a damped-driven system. We study a fluidic droplet in an annular cav...
2301.06041v2
2023-03-01
Generation of intraparticle quantum correlations in amplitude damping channel and its robustness
Quantum correlations between two or more different degrees of freedom of the same particle is sometimes referred to as intraparticle entanglement. In this work, we study these intra-particle correlations between two different degrees of freedom under various decoherence channels viz. amplitude damping, depolarising and...
2303.01238v1
2023-03-07
Electrically tunable Gilbert damping in van der Waals heterostructures of two-dimensional ferromagnetic metals and ferroelectrics
Tuning the Gilbert damping of ferromagnetic (FM) metals via a nonvolatile way is of importance to exploit and design next-generation novel spintronic devices. Through systematical first-principles calculations, we study the magnetic properties of the van der Waals heterostructure of two-dimensional FM metal CrTe2 and f...
2303.03852v1
2023-03-16
Quantum Brownian Motion in the Caldeira-Leggett Model with a Damped Environment
We model a quantum system coupled to an environment of damped harmonic oscillators by following the approach of Caldeira-Leggett and adopting the Caldirola-Kanai Lagrangian for the bath oscillators. In deriving the master equation of the quantum system of interest (a particle in a general potential), we show that the p...
2303.09516v1
2023-03-22
A Numerical Study of Landau Damping with PETSc-PIC
We present a study of the standard plasma physics test, Landau damping, using the Particle-In-Cell (PIC) algorithm. The Landau damping phenomenon consists of the damping of small oscillations in plasmas without collisions. In the PIC method, a hybrid discretization is constructed with a grid of finitely supported basis...
2303.12620v1
2023-04-07
Shifted shock formation for the 3D compressible Euler equations with damping and variation of the vorticity
In this paper, we consider the shock formation problem for the 3-dimensional(3D) compressible Euler equations with damping inspired by the work \cite{BSV3Dfulleuler}. It will be shown that for a class of large data, the damping can not prevent the formation of point shock, and the damping effect shifts the shock time a...
2304.03506v2
2023-07-05
Bayesian evidence for two slow-wave damping models in hot coronal loops
We compute the evidence in favour of two models, one based on field-aligned thermal conduction alone and another that includes thermal misbalance as well, in explaining the damping of slow magneto-acoustic waves in hot coronal loops. Our analysis is based on the computation of the marginal likelihood and the Bayes fact...
2307.02439v1
2023-07-24
From characteristic functions to multivariate distribution functions and European option prices by the damped COS method
We provide a unified framework for the computation of the distribution function and the computation of prices of financial options from the characteristic function of some density by the COS method. The classical COS method is numerically very efficient in one-dimension but cannot deal very well with certain financial ...
2307.12843v6
2023-07-26
A Nonlinear Damped Metamaterial: Wideband Attenuation with Nonlinear Bandgap and Modal Dissipation
In this paper, we incorporate the effect of nonlinear damping with the concept of locally resonant metamaterials to enable vibration attenuation beyond the conventional bandgap range. The proposed design combines a linear host cantilever beam and periodically distributed inertia amplifiers as nonlinear local resonators...
2307.14165v2
2023-07-28
Premature jump-down mimicks nonlinear damping in nanoresonators
Recent experiments on nano-resonators in a bistable regime use the `jump-down' point between states to infer mechanical properties of the membrane or a load, but often suggest the presence of some nonlinear damping. Motivated by such experiments, we develop a mechanical model of a membrane subject to a uniform, oscilla...
2307.15656v1
2023-09-22
Long time energy averages and a lower resolvent estimate for damped waves
We consider the damped wave equation on a compact manifold. We propose different ways of measuring decay of the energy (time averages of lower energy levels, decay for frequency localized data...) and exhibit links with resolvent estimates on the imaginary axis. As an application we prove a universal logarithmic lower ...
2309.12709v1
2023-10-11
Damping Density of an Absorptive Shoebox Room Derived from the Image-Source Method
The image-source method is widely applied to compute room impulse responses (RIRs) of shoebox rooms with arbitrary absorption. However, with increasing RIR lengths, the number of image sources grows rapidly, leading to slow computation. In this paper, we derive a closed-form expression for the damping density, which ch...
2310.07363v1
2023-10-14
Exploring Damping Effect of Inner Control Loops for Grid-Forming VSCs
This paper presents an analytical approach to explore the damping effect of inner loops on grid-forming converters. First, an impedance model is proposed to characterize the behaviors of inner loops, thereby illustrating their influence on output impedance shaping. Then, based on the impedance representation, the compl...
2310.09660v1
2023-10-24
Frictional weakening of a granular sheared layer due to viscous rolling revealed by Discrete Element Modeling
Considering a 3D sheared granular layer modeled with discrete elements, it is well known the rolling resistance significantly influences the mechanical behavior. Even if the rolling resistance role has been deeply investigated as it is commonly used to represent the the roughness of the grains and the interparticle loc...
2310.15945v1
2023-12-12
Coordination of Damping Controllers: A Data-Informed Approach for Adaptability
This work proposes a data-informed approach for an adaptable coordination of damping controllers. The novel concept of coordination is based on minimizing the Total Action, a single metric that measures the system's dynamic response post-disturbance. This is a performance measure based on the physics of the power syste...
2312.07739v1
2024-01-26
Efficient Control of Magnetization Dynamics Via W/CuO$_\text{x}$ Interface
Magnetization dynamics, which determine the speed of magnetization switching and spin information propagation, play a central role in modern spintronics. Gaining its control will satisfy the different needs of various spintronic devices. In this work, we demonstrate that the surface oxidized Cu (CuO$_\text{x}$) can be ...
2401.14708v1
2024-02-08
The stability analysis based on viscous theory of Faraday waves in Hele-Shaw cells
The linear instability of Faraday waves in Hele-Shaw cells is investigated with consideration of the viscosity of fluids after gap-averaging the governing equations due to the damping from two lateral walls and the dynamic behavior of contact angle. A new hydrodynamic model is thus derived and solved semi-analytically....
2402.05505v2
2024-04-08
Stability Enhancement of LCL-Type Grid-Following Inverters Using Capacitor Voltage Active Damping
An LCL filter offers superior attenuation for high-frequency harmonics for three-phase grid-following inverters compared to LC and L filters. However, it also introduces an inherent resonance peak, which can lead to power quality issues or even instability of the inverter control system. Active damping (AD) is widely e...
2404.05640v1
2024-04-10
Chemical Interface Damping by Electrochemical Gold Oxidation
Chemical interface damping is a change in the effective collision frequency of conduction band electrons in metal originating from a chemical change of the metal interface. In this work, we present in-situ ellipsometric measurements that reveal the chemical interface damping effect from electrochemical oxidation of sin...
2404.06799v1
1996-09-10
The Damping Tail of CMB Anisotropies
By decomposing the damping tail of CMB anisotropies into a series of transfer functions representing individual physical effects, we provide ingredients that will aid in the reconstruction of the cosmological model from small-scale CMB anisotropy data. We accurately calibrate the model-independent effects of diffusion ...
9609079v1
1997-09-16
Lyman-alpha emission as a tool to study high redshift damped systems
We report a quantitative study of the escape of Lyman-alpha photons from an inhomogeneous optically thick medium that mimics the structure of damped Lyman-alpha absorbers. Modeling the optically thick disk with 3 components (massive stars and HII regions, dust, and neutral hydrogen), we study the resulting emission lin...
9709150v1
1997-10-17
The chemical evolution of galaxies causing damped Ly$α$ absorption
We have compiled all available data on chemical abundances in damped Lyman alpha absorption systems for comparison with results from our combined chemical and spectrophotometric galaxy evolution models. Preliminary results from chemically consistent calculations are in agreement with observations of damped Ly$\alpha$ s...
9710193v1
1998-01-26
Are Damped Lyman alpha Systems Rotating Disks ?
We report on high spectral resolution observations of five damped Lyman alpha systems whose line velocity profiles and abundances are analyzed. By combining these data with information from the literature, we study the kinematics of the low and high ionization phases of damped systems and discuss the possibility that p...
9801243v1
2001-10-29
Damping of inhomogeneities in neutralino dark matter
The lightest supersymmetric particle, most likely the neutralino, might account for a large fraction of dark matter in the Universe. We show that the primordial spectrum of density fluctuations in neutralino cold dark matter (CDM) has a sharp cut-off due to two damping mechanisms: collisional damping during the kinetic...
0110601v1
2002-08-03
Adiabatic Index of Dense Matter and Damping of Neutron Star Pulsations
The adiabatic index Gamma_1 for perturbations of dense matter is studied under various physical conditions which can prevail in neutron star cores. The dependence of Gamma_1 on the composition of matter (in particular, on the presence of hyperons), on the stellar pulsation amplitude, and on the baryon superfluidity is ...
0208078v1
2003-01-07
Damping of Neutron Star Shear Modes by Superfluid Friction
The forced motion of superfluid vortices in shear oscillations of rotating solid neutron star matter produces damping of the mode. A simple model of the unpinning and repinning processes is described, with numerical calculations of the consequent energy decay times. These are of the order of 1 s or more for typical ano...
0301112v1
2005-04-25
Radiative Effect on Particle Acceleration via Relativistic Electromagnetic Expansion
The radiation damping effect on the diamagnetic relativistic pulse accelerator (DRPA) is studied in two-and-half dimensional Particle-in-Cell (PIC) simulation with magnetized electron-positron plasmas. Self-consistently solved radiation damping force converts particle energy to radiation energy. The DRPA is still robus...
0504561v1
1999-05-06
Collective and chaotic motion in self-bound many-body systems
We investigate the interplay of collective and chaotic motion in a classical self-bound N-body system with two-body interactions. This system displays a hierarchy of three well separated time scales that govern the onset of chaos, damping of collective motion and equilibration. Comparison with a mean-field problem show...
9905007v2
1997-05-12
Damping of Oscillations in Layer-by-Layer Growth
We present a theory for the damping of layer-by-layer growth oscillations in molecular beam epitaxy. The surface becomes rough on distances larger than a layer coherence length which is substantially larger than the diffusion length. The damping time can be calculated by a comparison of the competing roughening and smo...
9705100v1
1999-09-17
Thermoelastic Damping in Micro- and Nano-Mechanical Systems
The importance of thermoelastic damping as a fundamental dissipation mechanism for small-scale mechanical resonators is evaluated in light of recent efforts to design high-Q micrometer- and nanometer-scale electro-mechanical systems (MEMS and NEMS). The equations of linear thermoelasticity are used to give a simple der...
9909271v1
2000-10-01
Super-Radiance and the Unstable Photon Oscillator
If the damping of a simple harmonic oscillator from a thermally random force is sufficiently strong, then the oscillator may become unstable. For a photon oscillator (radiatively damped by electric dipole moments), the instability leads to a low temperature Hepp-Lieb-Preparata super-radiant phase transition. The stable...
0010013v1
2001-08-07
Non-damped Acoustic Plasmon and Superconductivity in Single Wall Carbon Nanotubes
We show that non-damped acoustic plasmons exist in single wall carbon nanotubes (SWCNT) and propose that the non-damped acoustic plasmons may mediate electron-electron attraction and result in superconductivity in the SWCNT. The superconducting transition temperature Tc for the SWCNT (3,3) obtained by this mechanism ag...
0108124v2
2001-10-11
Enhanced Gilbert Damping in Thin Ferromagnetic Films
Using a scattering matrix approach, the precession of the magnetization of a ferromagnet is shown to transfer spins into adjacent normal metal layers. This ``pumping'' of spins slows down the precession corresponding to an enhanced Gilbert damping factor in the Landau-Lifshitz equation. The damping is expressed in term...
0110247v2
2001-12-16
The Damping of the Bose-Condensate Oscillations in a Trap at Zero Temperature
We discuss an existence of the damping for the radial condensate oscillations in a cylindric trap at zero temperature. The damping is a result of the parametric resonance leading to energy transfer from the coherent condensate oscillations to the longitudinal sound waves within a finite frequency interval. The parametr...
0112292v1
2002-02-11
Radiation Induced Landau-Lifshitz-Gilbert Damping in Ferromagnets
The Landau-Lifshitz-Gilbert damping coefficient employed in the analysis of spin wave ferromagnetic resonance is related to the electrical conductivity of the sample. The changing magnetization (with time) radiates electromagnetic fields. The electromagnetic energy is then absorbed by the sample and the resulting heati...
0202181v1
2002-06-13
Beliaev damping of quasi-particles in a Bose-Einstein condensate
We report a measurement of the suppression of collisions of quasi-particles with ground state atoms within a Bose-Einstein condensate at low momentum. These collisions correspond to Beliaev damping of the excitations, in the previously unexplored regime of the continuous quasi-particle energy spectrum. We use a hydrody...
0206234v1
2002-06-28
Accidental suppression of Landau damping of the transverse breathing mode in elongated Bose-Einstein condensates
We study transverse radial oscillations of an elongated Bose-Einstein condensate using finite temperature simulations, in the context of a recent experiment at ENS. We demonstrate the existence of a mode corresponding to an in-phase collective oscillation of both the condensate and thermal cloud. Excitation of this mod...
0206582v1
2004-04-19
Nonlinear response of superparamagnets with finite damping: an analytical approach
The strongly damping-dependent nonlinear dynamical response of classical superparamagnets is investigated by means of an analytical approach. Using rigorous balance equations for the spin occupation numbers a simple approximate expression is derived for the nonlinear susceptibility. The results are in good agreement wi...
0404445v1
2004-09-24
Minimal field requirement in precessional magnetization switching
We investigate the minimal field strength in precessional magnetization switching using the Landau-Lifshitz-Gilbert equation in under-critically damped systems. It is shown that precessional switching occurs when localized trajectories in phase space become unlocalized upon application of field pulses. By studying the ...
0409671v1
2005-03-03
Collapse of thermal activation in moderately damped Josephson junctions
We study switching current statistics in different moderately damped Josephson junctions: a paradoxical collapse of the thermal activation with increasing temperature is reported and explained by interplay of two conflicting consequences of thermal fluctuations, which can both assist in premature escape and help in ret...
0503067v1
2006-01-10
Voltage dependence of Landau-Lifshitz-Gilbert damping of a spin in a current driven tunnel junction
We present a theory of Landau-Lifshitz-Gilbert damping $\alpha$ for a localized spin ${\vec S}$ in the junction coupled to the conduction electrons in both leads under an applied volatege $V$. We find the voltage dependence of the damping term reflecting the energy dependence of the density of states. We find the effec...
0601185v1
2006-03-13
Universal features of the defect-induced damping of lattice vibrations
It is shown that any defect gives an Ohmic contribution to the damping of any normal mode of the crystal lattice with nonzero wavevector which does not vanish at zero temperature. This explains the large phason damping observed at low temperatures in incommensurate phases, and might be a key factor to understand the li...
0603343v2
2006-04-25
Spin Precession and Avalanches
In many magnetic materials, spin dynamics at short times are dominated by precessional motion as damping is relatively small. In the limit of no damping and no thermal noise, we show that for a large enough initial instability, an avalanche can transition to an ergodic phase where the state is equivalent to one at fini...
0604563v1
2007-02-11
Non-Markovian coherence dynamics of driven spin boson model: damped quantum beat or large amplitude coherence oscillation
The dynamics of driven spin boson model is studied analytically by means of the perturbation approach based on a unitary transformation. We gave the analytical expression for the population difference and coherence of the two level system. The results show that in the weak driven case, the population difference present...
0702268v1
2005-05-10
Highly Damped Quasinormal Modes of Generic Single Horizon Black Holes
We calculate analytically the highly damped quasinormal mode spectra of generic single-horizon black holes using the rigorous WKB techniques of Andersson and Howls\cite{Andersson}. We thereby provide a firm foundation for previous analysis, and point out some of their possible limitations. The numerical coefficient in ...
0505044v1
2006-05-01
Stability and quasinormal modes of the massive scalar field around Kerr black holes
We find quasinormal spectrum of the massive scalar field in the background of the Kerr black holes. We show that all found modes are damped under the quasinormal modes boundary conditions when $\mu M$ is not large, thereby implying stability of the massive scalar field. This complements the region of stability determin...
0605013v1
1993-02-09
Damping rates for moving particles in hot QCD
Using a program of perturbative resummation I compute the damping rates for fields at nonzero spatial momentum to leading order in weak coupling in hot $QCD$. Sum rules for spectral densities are used to simplify the calculations. For massless fields the damping rate has an apparent logarithmic divergence in the infrar...
9302242v1
1994-04-21
Is \lq\lq Heavy Quark Damping Rate Puzzle'' in Hot QCD Really the Puzzle?
Within the framework of perturbative resummation scheme of Pisarski and Braaten, the decay- or damping-rate of a moving heavy quark (muon) to leading order in weak coupling in hot QCD (QED) is examined. Although, as is well known, the conventionally-defined damping rate diverges logarithmically at the infrared limit, s...
9404318v1
1996-01-12
Damping Rate of a Scalar Particle in Hot Scalar QED
In contrast to the damping of partons in a quark-gluon plasma, the damping of a scalar particle in a hot scalar QED plasma can be calculated to leading order for the whole momentum range using the Braaten-Pisarski method. In this way the evolution of the logarithmic infrared singularity caused by the exchange of a tran...
9601254v1
1996-09-17
Damping Rate of Quasiparticles in Degenerate Ultrarelativistic Plasmas
We compute the damping rate of a fermion in a dense relativistic plasma at zero temperature. Just above the Fermi sea, the damping rate is dominated by the exchange of soft magnetic photons (or gluons in QCD) and is proportional to $(E-\mu)$, where E is the fermion energy and $\mu$ the chemical potential. We also compu...
9609369v1
1997-05-28
Classical Statistical Mechanics and Landau Damping
We study the retarded response function in scalar $\phi^4$-theory at finite temperature. We find that in the high-temperature limit the imaginary part of the self-energy is given by the classical theory to leading order in the coupling. In particular the plasmon damping rate is a purely classical effect to leading orde...
9705452v1
1997-12-01
A potential infrared problem with the damping rates for gluons with soft momentum in hot QCD
We calculate the damping rate $\gamma_l$ for longitudinal gluons with zero momentum in finite high temperature QCD and show that some of its contributing terms are infrared divergent. This is in contrast with the expectation that this damping rate is to be equal to the corresponding one $\gamma_t$ for transverse gluons...
9712210v1
1998-04-21
The Plasmon Damping Rate for T -> T_C
The plasmon damping rate in scalar field theory is computed close to the critical temperature. It is shown that the divergent result obtained in perturbation theory is a consequence of neglecting the thermal renormalization of the coupling. Taking this effect into account, a vanishing damping rate is obtained, leading ...
9804351v2
1998-10-06
Self-consistent Study on Color Transport in the Quark Gluon Plasma at Finite Chemical Potential
We calculate the relaxation time self-consistently to study the damping of collective color modes and the color conductivity in a QGP by deriving self-consistent equations for the damping rates of gluons and quarks to leading order QCD by TFD including a chemical potential for quarks. We show that the damping rates are...
9810256v1
1999-02-19
The problem of nonlinear Landau damping in quark-gluon plasma
On the basis of the semiclassical equations for quark-gluon plasma (QGP) and Yang-Mills equation, the generalized kinetic equation for waves with regard to its interaction is obtained. The physical mechanisms defining nonlinear scattering of a plasmon by QGP particles are analysed. The problem on a connection of nonlin...
9902397v2
1999-07-21
A Slavnov-Taylor identity and equality of damping rates for static transverse and longitudinal gluons in hot QCD
A Slavnov-Taylor identity is derived for the gluon polarization tensor in hot QCD. We evaluate its implications for damping of gluonic modes in the plasma. Applying the identity to next to the leading order in hard-thermal-loop resummed perturbation theory, we derive the expected equality of damping rates for static tr...
9907439v1
2000-09-15
Fermion Damping Rate Effects in Cold Dense Matter
We review the non-Fermi or marginal liquid behavior of a relativistic QED plasma. In this medium a quasiparticle has a damping rate that depends linearly on the distance between its energy and the Fermi surface. We stress that this dependence is due to the long-range character of the magnetic interactions in the medium...
0009182v1
2001-07-19
Photon Damping Caused by Electron-Positron Pair Production in a Strong Magnetic Field
Damping of an electromagnetic wave in a strong magnetic field is analyzed in the kinematic region near the threshold of electron-positron pair production. Damping of the electromagnetic field is shown to be noticeably nonexponential in this region. The resulting width of the photon $\gamma \to e^+ e^-$ decay is conside...
0107217v1