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2022-07-01
Particle acceleration and radiation reaction in a strongly magnetized rotating dipole
Abridged. Neutron stars are surrounded by ultra-relativistic particles efficiently accelerated by ultra strong electromagnetic fields. However so far, no numerical simulations were able to handle such extreme regimes of very high Lorentz factors and magnetic field strengths. It is the purpose of this paper to study par...
2207.00624v1
2022-07-04
Selectivity of Protein Interactions Stimulated by Terahertz Signals
It has been established that Terahertz (THz) band signals can interact with biomolecules through resonant modes. Specifically, of interest here, protein activation. Our research goal is to show how directing the mechanical signaling inside protein molecules using THz signals can control changes in their structure and a...
2207.01572v1
2022-07-10
Revealing the drag instability in one-fluid nonideal MHD simulations of a 1D isothermal C-shock
C-type shocks are believed to be ubiquitous in turbulent molecular clouds thanks to ambipolar diffusion. We investigate whether the drag instability in 1D isothermal C-shocks, inferred from the local linear theory of Gu & Chen, can appear in non-ideal magnetohydrodynamic simulations. Two C-shock models (with narrow and...
2207.04355v2
2022-08-10
Theoretical model of a new type tunneling transistor
A tunneling transistor without heterojunction as a theoretical design, or more precisely controlled electron current transmission by barrier potential, is under consideration. The electrons from the conduction band of the source tunnel through the forbidden gap $E_g$ of the channel to the conduction band of the drain...
2208.05188v3
2022-08-11
Statistical distribution of HI 21cm intervening absorbers as potential cosmic acceleration probes
Damped Lyman-$\alpha$ Absorber (DLA), or HI 21cm Absorber (H21A), is an important probe to model-independently measure the acceleration of spectroscopic velocity ($v_\mathrm{S}$) via the Sandage-Loeb (SL) effect. Confined by the shortage of DLAs and Background Radio Sources (BRSs) with adequate information, the detecta...
2208.05639v3
2022-10-03
Quintom fields from chiral anisotropic cosmology
In this paper we present an analysis of a chiral anisotropic cosmological scenario from the perspective of quintom fields. In this setup quintessence and phantom fields interact in a non-standard (chiral) way within an anisotropic Bianchi type I background. We present our examination from two fronts: classical and quan...
2210.01186v2
2022-10-06
Effects of a Pre-inflationary de Sitter Bounce on the Primordial Gravitational Waves in $f(R)$ Gravity Theories
In this work we examine the effects of a pre-inflationary de Sitter bounce on the energy spectrum of the primordial gravitational waves. Specifically we assume that the Universe is described by several evolution patches, starting with a de Sitter pre-inflationary bounce which is followed by an quasi-de Sitter slow-roll...
2210.02861v1
2022-10-11
Switching Dynamics of Shallow Arches
This paper presents an analytical method to predict the delayed switching dynamics of nonlinear shallow arches while switching from one state to another state for different loading cases. We study an elastic arch subject to static loading and time-dependent loading separately. In particular, we consider a time-dependen...
2210.05734v2
2022-10-17
Pion dynamics in a soft-wall AdS-QCD model
Pseudo-Goldstone modes appear in many physical systems and display robust universal features. First, their mass $m$ obeys the so-called Gell-Mann-Oakes-Renner (GMOR) relation $f^2\,m^2=H\,\bar{\sigma}$, with $f$ the Goldstone stiffness, $H$ the explicit breaking scale and $\bar{\sigma}$ the spontaneous condensate. More...
2210.09088v1
2022-10-23
Robust Adaptive Prescribed-Time Control for Parameter-Varying Nonlinear Systems
It is an interesting open problem to achieve adaptive prescribed-time control for strict-feedback systems with unknown and fast or even abrupt time-varying parameters. In this paper we present a solution with the aid of several design and analysis innovations. First, by using a spatiotemporal transformation, we convert...
2210.12706v1
2022-11-22
Possible enhancement of the superconducting $T_c$ due to sharp Kohn-like soft phonon anomalies
Phonon softening is a ubiquitous phenomenon in condensed matter systems which is often associated with charge density wave (CDW) instabilities and anharmonicity. The interplay between phonon softening, CDW and superconductivity is a topic of intense debate. In this work, the effects of anomalous soft phonon instabiliti...
2211.12015v3
2022-11-22
Understanding Sparse Feature Updates in Deep Networks using Iterative Linearisation
Larger and deeper networks generalise well despite their increased capacity to overfit. Understanding why this happens is theoretically and practically important. One recent approach looks at the infinitely wide limits of such networks and their corresponding kernels. However, these theoretical tools cannot fully expla...
2211.12345v4
2023-01-23
(Non)-penalized Multilevel methods for non-uniformly log-concave distributions
We study and develop multilevel methods for the numerical approximation of a log-concave probability $\pi$ on $\mathbb{R}^d$, based on (over-damped) Langevin diffusion. In the continuity of \cite{art:egeapanloup2021multilevel} concentrated on the uniformly log-concave setting, we here study the procedure in the absence...
2301.09471v1
2023-02-02
The Power of Preconditioning in Overparameterized Low-Rank Matrix Sensing
We propose $\textsf{ScaledGD($\lambda$)}$, a preconditioned gradient descent method to tackle the low-rank matrix sensing problem when the true rank is unknown, and when the matrix is possibly ill-conditioned. Using overparametrized factor representations, $\textsf{ScaledGD($\lambda$)}$ starts from a small random initi...
2302.01186v3
2023-03-28
Nonlocal Nonholonomic Source Seeking Despite Local Extrema
In this paper, we investigate the problem of source seeking with a unicycle in the presence of local extrema. Our study is motivated by the fact that most of the existing source seeking methods follow the gradient direction of the signal function and thus only lead to local convergence into a neighborhood of the neares...
2303.16027v1
2023-04-18
A blue depression in the optical spectra of M dwarfs
A blue depression is found in the spectra of M dwarfs from 4000 to 4500A. This depression shows an increase toward lower temperatures though is particularly sensitive to gravity and metallicity. It is the single most sensitive feature in the optical spectra of M dwarfs. The depression appears as centered on the neutral...
2304.09219v2
2023-04-19
Thickness-dependent magnetic properties in Pt[CoNi]n multilayers with perpendicular magnetic anisotropy
We systematically investigated the Ni and Co thickness-dependent perpendicular magnetic anisotropy (PMA) coefficient, magnetic domain structures, and magnetization dynamics of Pt(5 nm)/[Co(t_Co nm)/Ni(t_Ni nm)]5/Pt(1 nm) multilayers by combining the four standard magnetic characterization techniques. The magnetic-relat...
2304.09366v1
2023-04-25
Flow-induced oscillations of pitching swept wings: Stability boundary, vortex dynamics and force partitioning
We experimentally study the aeroelastic instability boundaries and three-dimensional vortex dynamics of pitching swept wings, with the sweep angle ranging from 0 to 25 degrees. The structural dynamics of the wings are simulated using a cyber-physical control system. With a constant flow speed, a prescribed high inertia...
2304.12544v2
2023-07-04
Exponential stability of Euler-Bernoulli beam under boundary controls in rotation and angular velocity
This paper addresses the analysis of a boundary feedback system involving a non-homogeneous Euler-Bernoulli beam governed by the equation $m(x)u_{tt}+\mu(x)u_{t}$$+\left(r(x)u_{xx}\right)_{xx}=0$, subject to the initial $u(x,0)=u_0(x)$, $u_t(x,0)=v_0(x)$ and boundary conditions $u(0,t)=0$, $\left (-r(x)u_{xx}(x,t)\righ...
2307.01518v1
2023-07-13
Exciton-polaritons in CsPbBr$_3$ crystals revealed by optical reflectivity in high magnetic fields and two-photon spectroscopy
Cesium lead bromide (CsPbBr$_3$) is a representative material of the emerging class of lead halide perovskite semiconductors that possess remarkable optoelectronic properties. Its optical properties in the vicinity of the band gap energy are greatly contributed by excitons, which form exciton-polaritons due to strong l...
2307.07035v1
2023-07-19
Impact of bulk viscosity on the post-merger gravitational-wave signal from merging neutron stars
In the violent post-merger of binary neutron-star mergers strong oscillations are present that impact the emitted gravitational-wave (GW) signal. The frequencies, temperatures and densities involved in these oscillations allow for violations of the chemical equilibrium promoted by weak-interactions, thus leading to a n...
2307.10464v1
2023-07-21
Non-ideal magnetohydrodynamics on a moving mesh I: Ohmic and ambipolar diffusion
Especially in cold and high-density regions, the assumptions of ideal magnetohydrodynamics (MHD) can break down, making first order non-ideal terms such as Ohmic and ambipolar diffusion as well as the Hall effect important. In this study we present a new numerical scheme for the first two resistive terms, which we impl...
2307.11814v1
2023-09-14
The cost of solving linear differential equations on a quantum computer: fast-forwarding to explicit resource counts
How well can quantum computers simulate classical dynamical systems? There is increasing effort in developing quantum algorithms to efficiently simulate dynamics beyond Hamiltonian simulation, but so far exact resource estimates are not known. In this work, we provide two significant contributions. First, we give the f...
2309.07881v2
2023-09-18
Coherent Tunneling and Strain Sensitivity of an All Heusler Alloy Magnetic Tunneling Junction: A First-Principles Study
Half-metallic Co-based full Heusler alloys have captured considerable attention of the researchers in the realm of spintronic applications, owing to their remarkable characteristics such as exceptionally high spin polarization at Fermi level, ultra-low Gilbert damping, and high Curie temperature. In this comprehensive ...
2309.09755v1
2023-09-25
Domain wall dynamics driven by a transient laser-induced magnetisation
One of the fundamental effects of the laser-matter interaction is the appearance of an induced transient magnetisation. While the underlying phenomena differ in their microscopic origin and cover a diverse array of materials, here we address a fundamental question about the possibility to drive domain-wall dynamics on ...
2309.14287v1
2023-10-03
Controlled Quasi-Latitudinal Solutions for ultra-fast Spin-Torque Precessional Magnetization Switching
The aim of the paper is to present a novel class of time-dependent controls to realize ultra-fast magnetization switching in nanomagnets driven by spin-torques produced by spin-polarized electric currents. Magnetization dynamics in such systems is governed by the Landau-Lifshitz-Slonczewski equation which describes the...
2310.02070v1
2023-09-29
A Fast second-order solver for stiff multifluid dust and gas hydrodynamics
We present MDIRK: a Multifluid second-order Diagonally-Implicit Runge-Kutta method to study momentum transfer between gas and an arbitrary number ($N$) of dust species. The method integrates the equations of hydrodynamics with an Implicit Explicit (IMEX) scheme and solves the stiff source term in the momentum equation ...
2310.04435v3
2023-10-19
Error-mitigated fermionic classical shadows on noisy quantum devices
Efficiently estimating the expectation values of fermionic Hamiltonians, including $k$-particle reduced density matrices ($k$-RDMs) of an $n$-mode fermionic state, is crucial for quantum simulations of a wealth of physical systems from the fields of many-body physics, chemistry, and materials. Yet, conventional quantum...
2310.12726v2
2023-11-02
Phase space noncommutativity, power-law inflation and quantum cosmology
Considering an arbitrary dimensional FLRW universe in the framework of a generalized S\'{a}ez--Ballester (SB) theory, we establish a noncommutative (NC) cosmological model. We concentrate on the predictions of NC model and compare them with their commutative counterparts in both the classical and quantum regimes. For t...
2311.01627v1
2023-11-04
Electronic quantum wires in extended quasiparticle picture
A one-dimensional quantum wire of Fermions is considered and ground state properties are calculated in the high density regime within the extended quasiparticle picture and Born approximation. Expanding the two-particle Green functions determines the selfenergy and the polarization as well as the response function on t...
2311.02414v1
2023-11-14
Berry curvature induced giant intrinsic spin-orbit torque in single layer magnetic Weyl semimetal thin films
Topological quantum materials can exhibit unconventional surface states and anomalous transport properties, but their applications to spintronic devices are restricted as they require the growth of high-quality thin films with bulk-like properties. Here, we study 10--30 nm thick epitaxial ferromagnetic Co$_{\rm 2}$MnGa...
2311.08145v2
2023-12-26
All solution grown epitaxial magnonic crystal of thulium iron garnet thin film
Magnonics has shown the immense potential of compatibility with CMOS devices and the ability to be utilized in futuristic quantum computing. Therefore, the magnonic crystals, both metallic and insulating, are under extensive exploration. The presence of high spin-orbit interaction induced by the presence of rare-earth ...
2312.15973v1
2023-12-01
Large enhancement of spin-orbit torques under a MHz modulation due to phonon-magnon coupling
The discovery of spin-orbit torques (SOTs) generated through the spin Hall or Rashba effects provides an alternative write approach for magnetic random-access memory (MRAM), igniting the development of spin-orbitronics in recent years. Quantitative characterization of SOTs highly relies on the SOT-driven ferromagnetic ...
2401.02967v1
2024-01-25
Photon propagation in a charged Bose-Einstein condensate
We consider the propagation of photons in the background of a Bose-Einstein (BE) condensate of a charged scalar field, by extending a method recently proposed to treat the propagation of fermions in a BE condensate. We determine the dispersion relations of the collective modes of the system, as well as the photon polar...
2401.13896v1
2024-01-26
Well-posedness and stability of the Navier-Stokes-Maxwell equations
The paper is devoted to studying the well-posedness and stability of the generalized Navier-Stokes-Maxwell (NSM) equations with the standard Ohm's law in $\mathbb{R}^d$ for $d \in \{2,3\}$. More precisely, the global well-posedness is established in case of fractional Laplacian velocity $(-\Delta)^\alpha v$ with $\alph...
2401.14839v2
2024-03-14
The effect of spatially-varying collision frequency on the development of the Rayleigh-Taylor instability
The Rayleigh-Taylor (RT) instability is ubiquitously observed, yet has traditionally been studied using ideal fluid models. Collisionality can vary strongly across the fluid interface, and previous work demonstrates the necessity of kinetic models to completely capture dynamics in certain collisional regimes. Where pre...
2403.09591v1
2024-04-11
The Cattaneo-Christov approximation of Fourier heat-conductive compressible fluids
We investigate the Navier-Stokes-Cattaneo-Christov (NSC) system in $\mathbb{R}^d$ ($d\geq3$), a model of heat-conductive compressible flows serving as a finite speed of propagation approximation of the Navier-Stokes-Fourier (NSF) system. Due to the presence of Oldroyd's upper-convected derivatives, the system (NSC) exh...
2404.07809v1
2003-10-29
Comparing Chemical Abundances of the Damped Lya Systems and Metal-Poor Stars
I briefly draw comparisons between the fields of damped Lya and metal-poor stellar abundances. In particular, I examine their complementary age-metallicity relations and comparisons between the damped Lya and dwarf galaxy abundance patterns. Regarding the latter, I describe a series of problems concerning associating h...
0310850v1
2006-12-01
Stochastic excitation and damping of solar-type oscillations
A review on acoustic mode damping and excitation in solar-type stars is presented. Current models for linear damping rates are discussed in the light of recent low-degree solar linewidth measurements with emphasis on the frequency-dependence of damping rates of low-order modes. Recent developments in stochastic excitat...
0612024v1
1997-08-11
A theoretical study on the damping of collective excitations in a Bose-Einstein condensate
We study the damping of low-lying collective excitations of condensates in a weakly interacting Bose gas model within the framework of imaginary time path integral. A general expression of the damping rate has been obtained in the low momentum limit for both the very low temperature regime and the higher temperature re...
9708080v3
1997-09-24
Damping in dilute Bose gases: a mean-field approach
Damping in a dilute Bose gas is investigated using a mean-field approximation which describes the coupled oscillations of condensate and non-condensate atoms in the collisionless regime. Explicit results for both Landau and Beliaev damping rates are given for non-uniform gases. In the case of uniform systems we obtain ...
9709259v1
2000-09-01
Damped Bogoliubov excitations of a condensate interacting with a static thermal cloud
We calculate the damping of condensate collective excitations at finite temperatures arising from the lack of equilibrium between the condensate and thermal atoms. We neglect the non-condensate dynamics by fixing the thermal cloud in static equilibrium. We derive a set of generalized Bogoliubov equations for finite tem...
0009021v2
2000-11-20
Cavity assisted quasiparticle damping in a Bose-Einstein condensate
We consider an atomic Bose-Einstein condensate held within an optical cavity and interacting with laser fields. We show how the interaction of the cavity mode with the condensate can cause energy due to excitations to be coupled to a lossy cavity mode, which then decays, thus damping the condensate, how to choose param...
0011341v2
2002-12-16
The nonlinear damping of Bose-Einstein condensate oscillations at ultra-low temperatures
We analyze the damping of the transverse breathing mode in an elongated trap at ultralow temperatures. The damping occurs due to the parametric resonance entailing the energy transfer to the longitudinal degrees of freedom. It is found that the nonlinear coupling between the transverse and discrete longitudinal modes c...
0212377v2
2004-08-27
Tunable magnetization damping in transition metal ternary alloys
We show that magnetization damping in Permalloy, Ni80Fe20 (``Py''), can be enhanced sufficiently to reduce post-switching magnetization precession to an acceptable level by alloying with the transition metal osmium (Os). The damping increases monotonically upon raising the Os-concentration in Py, at least up to 9% of O...
0408608v1
2005-03-06
Nonlinear damping in nanomechanical beam oscillator
We investigate the impact of nonlinear damping on the dynamics of a nanomechanical doubly clamped beam. The beam is driven into nonlinear regime and the response is measured by a displacement detector. For data analysis we introduce a nonlinear damping term to Duffing equation. The experiment shows conclusively that ac...
0503130v2
2006-05-23
The origin of increase of damping in transition metals with rare earth impurities
The damping due to rare earth impurities in transition metals is discussed in the low concentration limit. It is shown that the increase in damping is mainly due to the coupling of the orbital moments of the rare earth impurities and the conduction $p$-electrons. It is shown that an itinerant picture for the host trans...
0605583v1
2001-05-14
Simplified models of electromagnetic and gravitational radiation damping
In previous work the authors analysed the global properties of an approximate model of radiation damping for charged particles. This work is put into context and related to the original motivation of understanding approximations used in the study of gravitational radiation damping. It is examined to what extent the res...
0105045v1
1994-06-07
Damping Rate of a Yukawa Fermion at Finite Temperature
The damping of a massless fermion coupled to a massless scalar particle at finite temperature is considered using the Braaten-Pisarski resummation technique. First the hard thermal loop diagrams of this theory are extracted and effective Green's functions are constructed. Using these effective Green's functions the dam...
9406242v1
2006-05-02
Moduli decay in the hot early Universe
We consider moduli fields interacting with thermalized relativistic matter. We determine the temperature dependence of their damping rate and find it is dominated by thermal effects in the high temperature regime, i.e. for temperatures larger than their mass. For a simple scalar model the damping rate is expressed thro...
0605030v2
2006-11-27
Inviscid limit for damped and driven incompressible Navier-Stokes equations in ${{\mathbb R}^2}$
We consider the zero viscosity limit of long time averages of solutions of damped and driven Navier-Stokes equations in ${\mathbb R}^2$. We prove that the rate of dissipation of enstrophy vanishes. Stationary statistical solutions of the damped and driven Navier-Stokes equations converge to renormalized stationary stat...
0611782v1
2001-11-25
The Landau Damping Effect and Complex-valued Nature of Physical Quantities
Within the framework of the hypothesis offered by authors about complex-valued nature of physical quantities, the effect of the Landau damping has been explored with assumption that not only frequency can be a small imaginary component but also a wave vector. The numerical solution of the obtained dispersion equation t...
0111176v1
2005-10-14
Nontrapping arrest of Langmuir wave damping near the threshold amplitude
Evolution of a Langmuir wave is studied numerically for finite amplitudes slightly above the threshold which separates damping from nondamping cases. Arrest of linear damping is found to be a second-order effect due to ballistic evolution of perturbations, resonant power transfer between field and particles, and organi...
0510131v3
2000-06-22
Decoherence and Entanglement in Two-mode Squeezed Vacuum States
I investigate the decoherence of two-mode squeezed vacuum states by analyzing the relative entropy of entanglement. I consider two sources of decoherence: (i) the phase damping and (ii) the amplitude damping due to the coupling to the thermal environment. In particular, I give the exact value of the relative entropy of...
0006100v1
2006-08-02
Damped Population Oscillation in a Spontaneously Decaying Two-Level Atom Coupled to a Monochromatic Field
We investigate the time evolution of atomic population in a two-level atom driven by a monochromatic radiation field, taking spontaneous emission into account. The Rabi oscillation exhibits amplitude damping in time caused by spontaneous emission. We show that the semiclassical master equation leads in general to an ov...
0608020v1
2006-11-23
Analytical solutions for two-level systems with damping
A method is proposed to transform any analytic solution of the Bloch equation into an analytic solution of the Landau-Lifshitz-Gilbert equation. This allows for the analytical description of the dynamics of a two level system with damping. This method shows that damping turns the linear Schr\"{o}dinger equation of a tw...
0611238v1
2007-06-12
Gilbert and Landau-Lifshitz damping in the presense of spin-torque
A recent article by Stiles et al. (cond-mat/0702020) argued in favor of the Landau-Lifshitz damping term in the micromagnetic equations of motion over that of the more commonly accepted Gilbert damping form. Much of their argument revolved around spin-torque driven domain wall motion in narrow magnetic wires, since the...
0706.1736v1
2008-04-04
Inhomogeneous Gilbert damping from impurities and electron-electron interactions
We present a unified theory of magnetic damping in itinerant electron ferromagnets at order $q^2$ including electron-electron interactions and disorder scattering. We show that the Gilbert damping coefficient can be expressed in terms of the spin conductivity, leading to a Matthiessen-type formula in which disorder and...
0804.0820v2
2008-12-18
Dipole Oscillations of a Fermi Gas in a Disordered Trap: Damping and Localization
We theoretically study the dipole oscillations of an ideal Fermi gas in a disordered trap. We show that even weak disorder induces strong damping of the oscillations and we identify a metal-insulator crossover. For very weak disorder, we show that damping results from a dephasing effect related to weak random perturbat...
0812.3501v2
2009-03-11
Confronting the damping of the baryon acoustic oscillations with observation
We investigate the damping of the baryon acoustic oscillations in the matter power spectrum due to the quasinonlinear clustering and redshift-space distortions by confronting the models with the observations of the Sloan Digital Sky Survey luminous red galaxy sample. The chi-squared test suggests that the observed powe...
0903.1883v1
2009-04-10
Spectral deviations for the damped wave equation
We prove a Weyl-type fractal upper bound for the spectrum of the damped wave equation, on a negatively curved compact manifold. It is known that most of the eigenvalues have an imaginary part close to the average of the damping function. We count the number of eigenvalues in a given horizontal strip deviating from this...
0904.1736v1
2009-10-26
Pressure Fronts in 1D Damped Nonlinear Lattices
The propagation of pressure fronts (impact solutions) in 1D chains of atoms coupled by anharmonic potentials between nearest neighbor and submitted to damping forces preserving uniform motion, is investigated. Travelling fronts between two regions at different uniform pressures are found numerically and well approximat...
0910.4890v1
2010-01-12
Decoherence and damping in ideal gases
The particle and current densities are shown to display damping and undergo decoherence in ideal quantum gases. The damping is read off from the equations of motion reminiscent of the Navier-Stokes equations and shows some formal similarity with Landau damping. The decoherence leads to consistent density and current hi...
1001.1803v2
2010-05-14
The effect of spin magnetization in the damping of electron plasma oscillations
The effect of spin of particles in the propagation of plasma waves is studied using a semi-classical kinetic theory for a magnetized plasma. We focus in the simple damping effects for the electrostatic wave modes besides Landau damping. Without taking into account more quantum effects than spin contribution to Vlasov's...
1005.2573v1
2010-06-01
Recent Progress on a Manifold Damped and Detuned Structure for CLIC
A damped detuned structure for the main X-band linacs of CLIC is being investigated as an alternative design to the present baseline heavily damped structure. In our earlier designs we studied detuned structures, operating at 11.994 GHz, with a range of dipole bandwidths in order to ensure the structure satisfies beam ...
1006.0087v1
2010-07-21
Finite temperature damping of collective modes of a BCS-BEC crossover superfluid
A new mechanism is proposed to explain the puzzling damping of collective excitations, which was recently observed in the experiments of strongly interacting Fermi gases below the superfluid critical temperature on the fermionic (BCS) side of Feshbach resonance. Sound velocity, superfluid density and damping rate are c...
1007.3694v2
2010-08-04
Confinement induced by fermion damping in three-dimensional QED
The three-dimensional non-compact QED is known to exhibit weak confinement when fermions acquire a finite mass via the mechanism of dynamical chiral symmetry breaking. In this paper, we study the effect of fermion damping caused by elastic scattering on the classical potential between fermions. By calculating the vacuu...
1008.0736v2
2011-06-22
Highly Damped Quasinormal Modes and the Small Scale Structure of Quantum Corrected Black Hole Exteriors
Quasinormal modes provide valuable information about the structure of spacetime outside a black hole. There is also a conjectured relationship between the highly damped quasinormal modes and the semi-classical spectrum of the horizon area/entropy. In this paper, we show that for spacetimes characterized by more than on...
1106.4357v1
2012-02-20
Simple Non-Markovian Microscopic Models for the Depolarizing Channel of a Single Qubit
The archetypal one-qubit noisy channels ---depolarizing, phase-damping and amplitude-damping channels--- describe both Markovian and non-Markovian evolution. Simple microscopic models for the depolarizing channel, both classical and quantum, are considered. Microscopic models which describe phase damping and amplitude ...
1202.4210v4
2012-06-14
Damping of optomechanical disks resonators vibrating in air
We report on miniature GaAs disk optomechanical resonators vibrating in air in the radiofrequency range. The flexural modes of the disks are studied by scanning electron microscopy and optical interferometry, and correctly modeled with the elasticity theory for annular plates. The mechanical damping is systematically m...
1206.3032v1
2012-07-09
A Generalized Interpolation Inequality and its Application to the Stabilization of Damped Equations
In this paper, we establish a generalized H{\"o}lder's or interpolation inequality for weighted spaces in which the weights are non-necessarily homogeneous. We apply it to the stabilization of some damped wave-like evolution equations. This allows obtaining explicit decay rates for smooth solutions for more general cla...
1207.2030v2
2012-07-10
Conformation dependent damping and generalization of fluctuation-dissipation relation
Damping on an object generally depends on its conformation (shape size etc.). We consider the Langevin dynamics of a model system with a conformation dependent damping and generalize the fluctuation dissipation relation to fit in such a situation. We derive equilibrium distribution function for such a case which conver...
1207.2218v2
2012-10-30
On algebraic damping close to inhomogeneous Vlasov equilibria in multi-dimensional spaces
We investigate the asymptotic damping of a perturbation around inhomogeneous stable stationary states of the Vlasov equation in spatially multi-dimensional systems. We show that branch singularities of the Fourier-Laplace transform of the perturbation yield algebraic dampings. In two spatial dimensions, we classify the...
1210.8040v1
2013-04-07
Phenomenological model of anomalous magnon softening and damping in half-metallic manganites
To describe anomalous zone-boundary softening and damping of magnons in manganites we present a phenomenological two-fluid model containing ferromagnetic Fermi-liquid and non-Fermi-liquid components. The Fermi-liquid component accounts for softening of zone-boundary magnons and for the Landau damping of magnons in the ...
1304.1983v1
2013-04-25
Determination of Transverse Density Structuring from Propagating MHD Waves in the Solar Atmosphere
We present a Bayesian seismology inversion technique for propagating magnetohydrodynamic (MHD) transverse waves observed in coronal waveguides. The technique uses theoretical predictions for the spatial damping of propagating kink waves in transversely inhomogeneous coronal waveguides. It combines wave amplitude dampin...
1304.6869v1
2013-07-08
Optimal decay rate of the bipolar Euler-Poisson system with damping in $\mathbb{R}^3$
By rewriting a bipolar Euler-Poisson equations with damping into an Euler equation with damping coupled with an Euler-Poisson equation with damping, and using a new spectral analysis, we obtain the optimal decay results of the solutions in $L^2$-norm, which improve theose in \cite{Li3, Wu3}. More precisely, the velocit...
1307.2081v1
2013-07-27
Symmetry considerations on radiation damping
It is well known that a direct Lagrangian description of radiation damping is still missing. In this paper we will use a specific approach of this problem which is the standard way to treat the radiation damping problem. The objectives here are to construct: a N=2 supersymmetric extension for the model describing the r...
1307.7319v1
2014-02-10
Damping of a nanocantilever by paramagnetic spins
We compute damping of mechanical oscillations of a cantilever that contains flipping paramagnetic spins. This kind of damping is mandated by the dynamics of the total angular momentum, spin + mechanical. Rigorous expression for the damping rate is derived in terms of measurable parameters. The effect of spins on the qu...
1402.2326v1
2014-02-20
Long-time behavior of solutions of a BBM equation with generalized damping
We study the long-time behavior of the solution of a damped BBM equation $u_t + u_x - u_{xxt} + uu_x + \mathscr{L}_{\gamma}(u) = 0$. The proposed dampings $\mathscr{L}_{\gamma}$ generalize standards ones, as parabolic ($\mathscr{L}_{\gamma}(u)=-\Delta u$) or weak damping ($\mathscr{L}_{\gamma}(u)=\gamma u$) and allows ...
1402.5009v1
2014-02-24
N=2 supersymmetric radiation damping problem on a noncommutative plane
It is well known that a direct Lagrangian description of radiation damping is still missing. In this paper a specific approach of this problem was used, which is the standard way to treat the radiation damping problem. A $N=2$ supersymmetric extension for the model describing the radiation damping on the noncommutative...
1402.6996v1
2014-11-03
Renormalized solutions to the continuity equation with an integrable damping term
We consider the continuity equation with a nonsmooth vector field and a damping term. In their fundamental paper, DiPerna and Lions proved that, when the damping term is bounded in space and time, the equation is well posed in the class of distributional solutions and the solution is transported by suitable characteris...
1411.0451v1
2015-02-07
Landau Damping in a Mixture of Bose and Fermi Superfluids
We study the Landau damping in Bose-Fermi superfluid mixture at finite temperature. We find that at low temperature, the Landau damping rate will be exponentially suppressed at both the BCS side and the BEC side of Fermi superfluid. The momentum dependence of the damping rate is obtained, and it is quite different from...
1502.02116v1
2015-03-20
Applying a formula for generator redispatch to damp interarea oscillations using synchrophasors
If an interarea oscillatory mode has insufficient damping, generator redispatch can be used to improve its damping. We explain and apply a new analytic formula for the modal sensitivity to rank the best pairs of generators to redispatch. The formula requires some dynamic power system data and we show how to obtain that...
1503.06144v2
2016-01-21
Codeword Stabilized Quantum Codes for Asymmetric Channels
We discuss a method to adapt the codeword stabilized (CWS) quantum code framework to the problem of finding asymmetric quantum codes. We focus on the corresponding Pauli error models for amplitude damping noise and phase damping noise. In particular, we look at codes for Pauli error models that correct one or two ampli...
1601.05763v1
2016-02-08
On Boundary Damped Inhomogeneous Timoshenko Beams and Related Problems
We consider the model equations for the Timoshenko beam as a first order system in the framework of evolutionary equations. The focus is on boundary damping, which is implemented as a dynamic boundary condition. A change of material laws allows to include a large class of cases of boundary damping. By choosing a partic...
1602.02521v1
2016-02-13
Diffusion phenomena for the wave equation with space-dependent damping in an exterior domain
In this paper, we consider the asymptotic behavior of solutions to the wave equation with space-dependent damping in an exterior domain. We prove that when the damping is effective, the solution is approximated by that of the corresponding heat equation as time tends to infinity. Our proof is based on semigroup estimat...
1602.04318v1
2016-02-29
Robust quantum state recovery from amplitude damping within a mixed states framework
Due to the interaction with the environment, a quantum state is subjected to decoherence which becomes one of the biggest problems for practical quantum computation. Amplitude damping is one of the most important decoherence processes. Here, we show that general two-qubit mixed states undergoing an amplitude damping ca...
1602.08865v1
2016-07-21
Protecting and enhancing spin squeezing under decoherence using weak measurement
We propose an efficient method to protect spin squeezing under the action of amplitude-damping, depolarizing and phase-damping channels based on measurement reversal from weak measurement, and consider an ensemble of N independent spin-1/2 particles with exchange symmetry. We find that spin squeezing can be enhanced gr...
1607.06530v2
2016-08-02
Ferromagnetic Damping/Anti-damping in a Periodic 2D Helical surface; A Non-Equilibrium Keldysh Green Function Approach
In this paper, we investigate theoretically the spin-orbit torque as well as the Gilbert damping for a two band model of a 2D helical surface state with a Ferromagnetic (FM) exchange coupling. We decompose the density matrix into the Fermi sea and Fermi surface components and obtain their contributions to the electroni...
1608.00984v2
2016-09-05
Remarks on an elliptic problem arising in weighted energy estimates for wave equations with space-dependent damping term in an exterior domain
This paper is concerned with weighted energy estimates and diffusion phenomena for the initial-boundary problem of the wave equation with space-dependent damping term in an exterior domain. In this analysis, an elliptic problem was introduced by Todorova and Yordanov. This attempt was quite useful when the coefficient ...
1609.01063v2
2016-11-16
Finite-orbit-width effects on the geodesic acoustic mode in the toroidally rotating tokamak plasma
The Landau damping of geodesic acoustic mode (GAM) in a torodial rotating tokamak plasma is analytically investigated by taking into account the finite-orbit-width (FOW) resonance effect to the 3rd order. The analytical result is shown to agree well with the numerical solution. The dependence of the damping rate on the...
1611.05168v1
2017-03-09
Long-time dynamics of the strongly damped semilinear plate equation in $\mathbb{R}^{n}$
We investigate the initial-value problem for the semilinear plate equation containing localized strong damping, localized weak damping and nonlocal nonlinearity. We prove that if nonnegative damping coefficients are strictly positive almost everywhere in the exterior of some ball and the sum of these coefficients is po...
1703.03485v2
2017-04-21
The Effects of Rolling Deformation and Annealing Treatment on Damping Capacity of 1200 Aluminium Alloy
Annealing treatment is an important step of rolling deformation that contributes to microstructural evolution and leads to the significant changes in damping capacity. Damping capacities were analyzed in the parallel to rolling direction at 1 and 10 Hz respectively. It was found that severe plastic deformation at 40 pe...
1704.07362v1
2017-07-12
Isolated resonances and nonlinear damping
We analyze isolated resonance curves (IRCs) in a single-degree-of-freedom system with nonlinear damping. The adopted procedure exploits singularity theory in conjunction with the harmonic balance method. The analysis unveils a geometrical connection between the topology of the damping force and IRCs. Specifically, we d...
1707.03561v2
2017-07-25
Best exponential decay rate of energy for the vectorial damped wave equation
The energy of solutions of the scalar damped wave equation decays uniformly exponentially fast when the geometric control condition is satisfied. A theorem of Lebeau [leb93] gives an expression of this exponential decay rate in terms of the average value of the damping terms along geodesics and of the spectrum of the i...
1707.07893v1
2017-08-20
Radiation Damping of a Polarizable Particle
A polarizable body moving in an external electromagnetic field will slow down. This effect is referred to as radiation damping and is analogous to Doppler cooling in atomic physics. Using the principles of special relativity we derive an expression for the radiation damping force and find that it solely depends on the ...
1708.06628v1
2017-09-13
Energy decay for the Klein-Gordon equation with highly oscillating damping
We consider the free Klein-Gordon equation with periodic damping. We show on this simple model that if the usual geometric condition holds then the decay of the energy is uniform with respect to the oscillations of the damping, and in particular the size of the derivatives do not play any role. We also show that withou...
1709.04197v1
2017-11-01
Analysis of A Splitting Scheme for Damped Stochastic Nonlinear Schrödinger Equation with Multiplicative Noise
In this paper, we investigate the damped stochastic nonlinear Schr\"odinger(NLS) equation with multiplicative noise and its splitting-based approximation. When the damped effect is large enough, we prove that the solutions of the damped stochastic NLS equation and the splitting scheme are exponential stable and possess...
1711.00516v2
2017-12-31
Stabilization of the weakly coupled wave-plate system with one internal damping
This paper is addressed to a stabilization problem of a system coupled by a wave and a Euler-Bernoulli plate equation. Only one equation is supposed to be damped. Under some assumption about the damping and the coupling terms, it is shown that sufficiently smooth solutions of the system decay logarithmically at infinit...
1801.00232v1
2018-05-10
Dynamics of coherence-induced state ordering under Markovian channels
We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels: $-$ amplitude damping channel, phase damping channel, depolarizing channel and bit flit channel for single-qubit states. We show that the amplitude damping channel, phase damping channel, ...
1805.03898v1