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2024-03-07
The stochastic Ravine accelerated gradient method with general extrapolation coefficients
In a real Hilbert space domain setting, we study the convergence properties of the stochastic Ravine accelerated gradient method for convex differentiable optimization. We consider the general form of this algorithm where the extrapolation coefficients can vary with each iteration, and where the evaluation of the gradi...
2403.04860v2
1998-02-18
Damping rates of hot Giant Dipole Resonances
The damping rate of hot giant dipole resonances (GDR) is investigated. Besides Landau damping we consider collisions and density fluctuations as contributions to the damping of GDR. Within the nonequilibrium Green's function method we derive a non-Markovian kinetic equation. The linearization of the latter one leads to...
9802052v2
2015-12-11
Ultra-low magnetic damping of a metallic ferromagnet
The phenomenology of magnetic damping is of critical importance for devices that seek to exploit the electronic spin degree of freedom since damping strongly affects the energy required and speed at which a device can operate. However, theory has struggled to quantitatively predict the damping, even in common ferromagn...
1512.03610v1
2020-05-12
Effective Viscous Damping Enables Morphological Computation in Legged Locomotion
Muscle models and animal observations suggest that physical damping is beneficial for stabilization. Still, only a few implementations of mechanical damping exist in compliant robotic legged locomotion. It remains unclear how physical damping can be exploited for locomotion tasks, while its advantages as sensor-free, a...
2005.05725v2
2023-06-30
A finite element method to compute the damping rate of oscillating fluids inside microfluidic nozzles
We introduce a finite element method for computing the damping rate of fluid oscillations in nozzles of drop-on-demand (DoD) microfluidic devices. Accurate knowledge of the damping rates for the least-damped oscillation modes following droplet ejection is paramount for assessing jetting stability at higher jetting freq...
2307.00094v1
2023-07-05
Optimal damping of vibrating systems: dependence on initial conditions
Common criteria used for measuring performance of vibrating systems have one thing in common: they do not depend on initial conditions of the system. In some cases it is assumed that the system has zero initial conditions, or some kind of averaging is used to get rid of initial conditions. The aim of this paper is to i...
2307.02352v2
2024-01-18
Multithermal apparent damping of slow waves due to strands with a Gaussian temperature distribution
Context. Slow waves in solar coronal loops are strongly damped. The current theory of damping by thermal conduction cannot explain some observational features.\n Aims. We investigate the propagation of slow waves in a coronal loop built up from strands of different temperatures. \n Methods. We consider the loop to have...
2401.09803v1
2000-12-20
Possible evidence for a variable fine structure constant from QSO absorption lines: motivations, analysis and results
An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar absorption line spectra with laboratory spectra provides a sensitive probe for variability of the fine structure constant, alpha, over cosmological time-scales. W...
0012419v5
2006-06-04
k-Essence, Avoidance of the Weinberg's Cosmological Constant No-Go Theorem and Other Dark Energy Effects of Two Measures Field Theory
The dilaton-gravity sector of the Two Measures Field Theory (TMT) is explored in detail in the context of cosmology. The dilaton \phi dependence of the effective Lagrangian appears only as a result of the spontaneous breakdown of the scale invariance. If no fine tuning is made, the effective \phi-Lagrangian p(\phi,X) d...
0606017v2
2006-03-20
Higgs-Inflaton Symbiosis, Cosmological Constant Problem and Superacceleration Phase of the Universe in Two Measures Field Theory with Spontaneously Broken Scale Invariance
We study the scalar sector of the Two Measures Field Theory (TMT) model in the context of cosmological dynamics. The scalar sector includes the inflaton \phi and the Higgs \upsilon fields. The model possesses gauge and scale invariance. The latter is spontaneously broken due to intrinsic features of the TMT dynamics. I...
0603150v1
2020-10-28
Testing Gravity on Cosmic Scales: A Case Study of Jordan-Brans-Dicke Theory
We provide an end-to-end exploration of a distinct modified gravitational theory in Jordan-Brans-Dicke (JBD) gravity, from an analytical and numerical description of the background expansion and linear perturbations, to the nonlinear regime captured with a hybrid suite of $N$-body simulations, to the parameter constrai...
2010.15278v2
2022-01-31
A lower bound on the space overhead of fault-tolerant quantum computation
The threshold theorem is a fundamental result in the theory of fault-tolerant quantum computation stating that arbitrarily long quantum computations can be performed with a polylogarithmic overhead provided the noise level is below a constant level. A recent work by Fawzi, Grospellier and Leverrier (FOCS 2018) building...
2202.00119v2
1996-06-07
Abundances at High Redshifts: the Chemical Enrichment History of Damped Lyman-alpha Galaxies
Damped Lyman-alpha absorption systems found in the spectra of high redshift quasars are believed to trace the interstellar gas in high redshift galaxies. In this paper, we study the elemental abundances of C, N, O, Al, Si, S, Cr, Mn, Fe, Ni, and Zn in a sample of 14 damped Lyman-alpha systems using high quality echelle...
9606044v1
1998-07-17
Chaotic scattering on surfaces and collisional damping of collective modes
The damping of hot giant dipole resonances is investigated. The contribution of surface scattering is compared with the contribution from interparticle collisions. A unified response function is presented which includes surface damping as well as collisional damping. The surface damping enters the response via the Lyap...
9807185v4
2000-09-08
Probing High-Redshift Disks with Damped Lyman Alpha Systems
Evidence is presented that the damped Lyman alpha absorption systems are the high-redshift (z > 3) progenitors of galaxy disks. I discuss kinematic evidence that the damped Lyman Alpha systems are rotating disks. I also discuss implications of the lack of metal-poor damped Lyman alpha systems with line width Delta v > ...
0009126v1
2006-09-10
Damping of Compressional MHD Waves In Quiescent Prominences and Prominence-Corona Transition Region (PCTR)
The effects of radiative losses due to Newtonian cooling and MHD turbulence have been considered to examine the spatial damping of linear compressional waves in quiescent prominences and prominence-corona transition region (PCTR). The radiative losses give acceptable damping lengths for the slow mode wave for the radia...
0609266v1
1997-10-14
Damping of low-energy excitations of a trapped Bose condensate at finite temperatures
We present the theory of damping of low-energy excitations of a trapped Bose condensate at finite temperatures, where the damping is provided by the interaction of these excitations with the thermal excitations. We emphasize the key role of stochastization in the behavior of the thermal excitations for damping in non-s...
9710128v3
2001-12-09
Soliton dynamics in damped and forced Boussinesq equations
We investigate the dynamics of a lattice soliton on a monatomic chain in the presence of damping and external forces. We consider Stokes and hydrodynamical damping. In the quasi-continuum limit the discrete system leads to a damped and forced Boussinesq equation. By using a multiple-scale perturbation expansion up to s...
0112148v1
2006-04-17
The Highly Damped Quasinormal Modes of $d$-dimensional Reissner-Nordstrom Black Holes in the Small Charge Limit
We analyze in detail the highly damped quasinormal modes of $d$-dimensional Reissner-Nordstr$\ddot{\rm{o}}$m black holes with small charge, paying particular attention to the large but finite damping limit in which the Schwarzschild results should be valid. In the infinite damping limit, we confirm using different meth...
0604073v2
2005-02-16
Damping signatures in future neutrino oscillation experiments
We discuss the phenomenology of damping signatures in the neutrino oscillation probabilities, where either the oscillating terms or the probabilities can be damped. This approach is a possibility for tests of non-oscillation effects in future neutrino oscillation experiments, where we mainly focus on reactor and long-b...
0502147v2
2000-08-22
Local and Fundamental Mode Coupler Damping of the Transverse Wakefield in RDDS1 Linacs
In damping the wakefield generated by an electron beam traversing several thousand X-band linacs in the NLC we utilise a Gaussian frequency distribution of dipole modes to force the modes to deconstructively interfere, supplemented with moderate damping achieved by coupling these modes to four attached manifolds. Most ...
0008211v1
2007-10-25
Damping of Condensate Oscillation of a Trapped Bose Gas in a One-Dimensional Optical Lattice at Finite Temperatures
We study damping of a dipole oscillation in a Bose-Condensed gas in a combined cigar-shaped harmonic trap and one-dimensional (1D) optical lattice potential at finite temperatures. In order to include the effect of thermal excitations in the radial direction, we derive a quasi-1D model of the Gross-Pitaeavskii equation...
0710.4610v1
2008-01-03
Spin orbit precession damping in transition metal ferromagnets
We provide a simple explanation, based on an effective field, for the precession damping rate due to the spin-orbit interaction. Previous effective field treatments of spin-orbit damping include only variations of the state energies with respect to the magnetization direction, an effect referred to as the breathing Fer...
0801.0549v1
2009-02-03
Damping of filament thread oscillations: effect of the slow continuum
Transverse oscillations of small amplitude are commonly seen in high-resolution observations of filament threads, i.e. the fine-structures of solar filaments/prominences, and are typically damped in a few periods. Kink wave modes supported by the thread body offer a consistent explanation of these observed oscillations...
0902.0572v2
2010-11-23
Magnetohydrodynamic kink waves in two-dimensional non-uniform prominence threads
We analyse the oscillatory properties of resonantly damped transverse kink oscillations in two-dimensional prominence threads. The fine structures are modelled as cylindrically symmetric magnetic flux tubes with a dense central part with prominence plasma properties and an evacuated part, both surrounded by coronal pla...
1011.5175v2
2011-04-04
Plasmonic abilities of gold and silver spherical nanoantennas in terms of size dependent multipolar resonance frequencies and plasmon damping rates
Absorbing and emitting optical properties of a spherical plasmonic nanoantenna are described in terms of the size dependent resonance frequencies and damping rates of the multipolar surface plasmons (SP). We provide the plasmon size characteristics for gold and silver spherical particles up to the large size retardatio...
1104.0565v1
2011-11-16
Three-player quantum Kolkata restaurant problem under decoherence
Effect of quantum decoherence in a three-player quantum Kolkata restaurant problem is investigated using tripartite entangled qutrit states. Amplitude damping, depolarizing, phase damping, trit-phase flip and phase flip channels are considered to analyze the behaviour of players payoffs. It is seen that Alice's payoff ...
1111.3913v2
2012-07-27
The effect of non-uniform damping on flutter in axial flow and energy harvesting strategies
The problem of energy harvesting from flutter instabilities in flexible slender structures in axial flows is considered. In a recent study, we used a reduced order theoretical model of such a system to demonstrate the feasibility for harvesting energy from these structures. Following this preliminary study, we now cons...
1207.6484v1
2012-11-20
Damping rates of surface plasmons for particles of size from nano- to micrometers; reduction of the nonradiative decay
Damping rates of multipolar, localized surface plasmons (SP) of gold and silver nanospheres of radii up to $1000nm$ were found with the tools of classical electrodynamics. The significant increase in damping rates followed by noteworthy decrease for larger particles takes place along with substantial red-shift of plasm...
1211.4781v1
2013-10-23
Landau damping in a collisionless dipolar Bose gas
We present a theory for the Landau damping of low energy quasi-particles in a collisionless, quasi-2D dipolar Bose gas and produce expressions for the damping rate in uniform and non-uniform systems. Using simple energy-momentum conservation arguments, we show that in the homogeneous system, the nature of the low energ...
1310.6386v1
2014-11-28
Non-equilibrium thermodynamics of damped Timoshenko and damped Bresse systems
In this paper, we cast damped Timoshenko and damped Bresse systems into a general framework for non-equilibrium thermodynamics, namely the GENERIC (General Equation for Non-Equilibrium Reversible-Irreversible Coupling) framework. The main ingredients of GENERIC consist of five building blocks: a state space, a Poisson ...
1412.0038v2
2014-12-08
Bi-$\cal{PT}$ symmetry in nonlinearly damped dynamical systems and tailoring $\cal{PT}$ regions with position dependent loss-gain profiles
We investigate the remarkable role of position dependent damping in determining the parametric regions of symmetry breaking in nonlinear $\cal{PT}$-symmetric systems. We illustrate the nature of $\cal{PT}$-symmetry preservation and breaking with reference to a remarkable integrable scalar nonlinear system. In the two d...
1412.2574v3
2015-09-04
Damped transverse oscillations of interacting coronal loops
Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can...
1509.01487v1
2015-09-14
Beliaev damping in quasi-2D dipolar condensates
We study the effects of quasiparticle interactions in a quasi-two dimensional (quasi-2D), zero-temperature Bose-Einstein condensate of dipolar atoms, which can exhibit a roton-maxon feature in its quasiparticle spectrum. Our focus is the Beliaev damping process, in which a quasiparticle collides with the condensate and...
1509.04217v1
2015-12-08
Thermal energies of classical and quantum damped oscillators coupled to reservoirs
We consider the global thermal state of classical and quantum harmonic oscillators that interact with a reservoir. Ohmic damping of the oscillator can be exactly treated with a 1D scalar field reservoir, whereas general non-Ohmic damping is conveniently treated with a continuum reservoir of harmonic oscillators. Using ...
1512.02551v2
2016-05-17
Simultaneous Identification of Damping Coefficient and Initial Value in PDEs from boundary measurement
In this paper, the simultaneous identification of damping or anti-damping coefficient and initial value for some PDEs is considered. An identification algorithm is proposed based on the fact that the output of system happens to be decomposed into a product of an exponential function and a periodic function. The former ...
1605.05063v1
2016-08-30
Optimal damping ratios of multi-axial perfectly matched layers for elastic-wave modeling in general anisotropic media
The conventional Perfectly Matched Layer (PML) is unstable for certain kinds of anisotropic media. This instability is intrinsic and independent of PML formulation or implementation. The Multi-axial PML (MPML) removes such instability using a nonzero damping coefficient in the direction parallel with the interface betw...
1608.08326v3
2016-10-10
A Five-Freedom Active Damping and Alignment Device Used in the Joule Balance
Damping devices are necessary for suppressing the undesired coil motions in the watt/joule balance. In this paper, an active electromagnetic damping device, located outside the main magnet, is introduced in the joule balance project. The presented damping device can be used in both dynamic and static measurement modes....
1610.02799v1
2016-10-01
The destabilizing effect of external damping: Singular flutter boundary for the Pfluger column with vanishing external dissipation
Elastic structures loaded by nonconservative positional forces are prone to instabilities induced by dissipation: it is well-known in fact that internal viscous damping destabilizes the marginally stable Ziegler's pendulum and Pfluger column (of which the Beck's column is a special case), two structures loaded by a tan...
1611.03886v1
2017-10-10
A four-field gyrofluid model with neoclassical effects for the study of the rotation velocity of magnetic islands in tokamaks
A four-field system of equations which includes the neoclassical flow damping effects and the lowest-order finite-Larmor-radius (FLR) corrections is deduced from a system of gyrofluid equations. The FLR corrections to the poloidal flow damping are calculated by solving a simplified version of the gyrokinetic equation. ...
1710.03585v1
2017-10-13
Mode-Dependent Damping in Metallic Antiferromagnets Due to Inter-Sublattice Spin Pumping
Damping in magnetization dynamics characterizes the dissipation of magnetic energy and is essential for improving the performance of spintronics-based devices. While the damping of ferromagnets has been well studied and can be artificially controlled in practice, the damping parameters of antiferromagnetic materials ar...
1710.04766v1
2017-12-04
Resonance oscillation of a damped driven simple pendulum
The resonance characteristics of a driven damped harmonic oscillator are well known. Unlike harmonic oscillators which are guided by parabolic potentials, a simple pendulum oscillates under sinusoidal potentials. The problem of an undamped pendulum has been investigated to a great extent. However, the resonance charact...
1712.01032v1
2018-01-17
On Global Existence and Blow-up for Damped Stochastic Nonlinear Schrödinger Equation
In this paper, we consider the well-posedness of the weakly damped stochastic nonlinear Schr\"odinger(NLS) equation driven by multiplicative noise. First, we show the global existence of the unique solution for the damped stochastic NLS equation in critical case. Meanwhile, the exponential integrability of the solution...
1801.05630v1
2018-05-04
Effective damping enhancement in noncollinear spin structures
Damping mechanisms in magnetic systems determine the lifetime, diffusion and transport properties of magnons, domain walls, magnetic vortices, and skyrmions. Based on the phenomenological Landau-Lifshitz-Gilbert equation, here the effective damping parameter in noncollinear magnetic systems is determined describing the...
1805.01815v2
2018-05-16
Stabilization rates for the damped wave equation with Hölder-regular damping
We study the decay rate of the energy of solutions to the damped wave equation in a setup where the geometric control condition is violated. We consider damping coefficients which are $0$ on a strip and vanish like polynomials, $x^{\beta}$. We prove that the semigroup cannot be stable at rate faster than $1/t^{(\beta+2...
1805.06535v3
2018-08-20
Gilbert damping of [Co/Pd]n/Py multilayer thin films
Understanding the Gilbert damping in exchange-coupled multilayer materials is particularly important to develop future fast switching spintronics devices. Here, we report an experimental investigation of temperature-dependent Gilbert damping in [Co/Pd]n/Py multilayer films of varying the number of Co/Pd repetitions by ...
1808.06515v2
2019-03-01
Comprehensive Study of Neutrino-Dark Matter Mixed Damping
Mixed damping is a physical effect that occurs when a heavy species is coupled to a relativistic fluid which is itself free streaming. As a cross-case between collisional damping and free-streaming, it is crucial in the context of neutrino-dark matter interactions. In this work, we establish the parameter space relevan...
1903.00540v2
2019-08-04
Efficient spin excitation via ultrafast damping-like torques in antiferromagnets
Damping effects form the core of many emerging concepts for high-speed spintronic applications. Important characteristics such as device switching times and magnetic domain-wall velocities depend critically on the damping rate. While the implications of spin damping for relaxation processes are intensively studied, dam...
1908.01359v3
2019-10-31
Gyrokinetic investigation of the damping channels of Alfvén modes in ASDEX Upgrade
The linear destabilization and nonlinear saturation of energetic-particle driven Alfv\'enic instabilities in tokamaks strongly depend on the damping channels. In this work, the collisionless damping mechanisms of Alfv\'enic modes are investigated within a gyrokinetic framework, by means of global simulations with the p...
1910.14489v1
2020-03-13
Anharmonic phonon damping enhances the $T_c$ of BCS-type superconductors
A theory of superconductivity is presented where the effect of anharmonicity, as entailed in the acoustic, or optical, phonon damping, is explicitly considered in the pairing mechanism. The gap equation is solved including diffusive Akhiezer damping for longitudinal acoustic phonons or Klemens damping for optical phono...
2003.06220v2
2020-03-29
Stability results for an elastic-viscoelastic waves interaction systems with localized Kelvin-Voigt damping and with an internal or boundary time delay
We investigate the stability of a one-dimensional wave equation with non smooth localized internal viscoelastic damping of Kelvin-Voigt type and with boundary or localized internal delay feedback. The main novelty in this paper is that the Kelvin-Voigt and the delay damping are both localized via non smooth coefficient...
2003.12967v1
2020-09-16
Fast convex optimization via inertial dynamics combining viscous and Hessian-driven damping with time rescaling
In a Hilbert setting, we develop fast methods for convex unconstrained optimization. We rely on the asymptotic behavior of an inertial system combining geometric damping with temporal scaling. The convex function to minimize enters the dynamic via its gradient. The dynamic includes three coefficients varying with time,...
2009.07620v1
2020-12-27
Quantum speed limit time in relativistic frame
We investigate the roles of the relativistic effect on the speed of evolution of a quantum system coupled with amplitude damping channels. We find that the relativistic effect speed-up the quantum evolution to a uniform evolution speed of open quantum systems for the damping parameter $p_{\tau}\lesssim p_{\tau_{c0}}.$ ...
2012.13859v2
2021-01-07
Mechanisms behind large Gilbert damping anisotropies
A method with which to calculate the Gilbert damping parameter from a real-space electronic structure method is reported here. The anisotropy of the Gilbert damping with respect to the magnetic moment direction and local chemical environment is calculated for bulk and surfaces of Fe$_{50}$Co$_{50}$ alloys from first pr...
2101.02794v2
2021-06-23
Regularization of central forces with damping in two and three-dimensions
Regularization of damped motion under central forces in two and three-dimensions are investigated and equivalent, undamped systems are obtained. The dynamics of a particle moving in $\frac{1}{r}$ potential and subjected to a damping force is shown to be regularized a la Levi-Civita. We then generalize this regularizati...
2106.12134v1
2021-07-06
Theory of vibrators with variable-order fractional forces
In this paper, we present a theory of six classes of vibrators with variable-order fractional forces of inertia, damping, and restoration. The novelty and contributions of the present theory are reflected in six aspects. 1) Equivalent motion equations of those variable-order fractional vibrators are proposed. 2) The an...
2107.02340v2
2021-08-15
Exponential stability of a damped beam-string-beam transmission problem
We consider a beam-string-beam transmission problem, where two structurally damped or undamped beams are coupled with a frictionally damped string by transmission conditions. We show that for this type of structure, the dissipation produced by the frictional part is strong enough to produce exponential decay of the sol...
2108.06749v1
2021-09-10
Fourth-order dynamics of the damped harmonic oscillator
It is shown that the classical damped harmonic oscillator belongs to the family of fourth-order Pais-Uhlenbeck oscillators. It follows that the solutions to the damped harmonic oscillator equation make the Pais-Uhlenbeck action stationary. Two systematic approaches are given for deriving the Pais-Uhlenbeck action from ...
2109.06034v1
2022-01-13
Damping of Alfvén waves in MHD turbulence and implications for cosmic ray streaming instability and galactic winds
Alfv\'{e}nic component of MHD turbulence damps Alfv\'{e}nic waves. The consequences of this effect are important for many processes, from cosmic ray (CR) propagation to launching outflows and winds in galaxies and other magnetized systems. We discuss the differences in the damping of the streaming instability by turbul...
2201.05168v1
2022-03-14
Investigation of nonlinear squeeze-film damping involving rarefied gas effect in micro-electro-mechanical-systems
In this paper, the nonlinear squeeze-film damping (SFD) involving rarefied gas effect in the micro-electro-mechanical-systems (MEMS) is investigated. Considering the motion of structures (beam, cantilever, and membrane) in MEMS, the dynamic response of structure will be influenced largely by the squeeze-film damping. I...
2203.06902v1
2022-05-21
Noether symmetries and first integrals of damped harmonic oscillator
Noether theorem establishes an interesting connection between symmetries of the action integral and conservation laws of a dynamical system. The aim of the present work is to classify the damped harmonic oscillator problem with respect to Noether symmetries and to construct corresponding conservation laws for all over-...
2205.10525v1
2023-01-31
The emergence of soft-glassy mechanics in simulated foams
Several seemingly different soft materials, including foams, cells, and many complex fluids, exhibit remarkably similar rheological properties and microscopic dynamics, termed soft glassy mechanics. Here, we show that such behavior emerges from a simple model of a damped ripening foam, for sufficiently weak damping. In...
2301.13400v1
2023-02-13
Thickness and temperature dependent damping in La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ epitaxial films
The damping of La0.67Sr0.33MnO3 (LSMO) epitaxial films as a function of thickness at different temperatures was studied. The competition between two scattering types (\r{ho}-like and {\sigma}-like) with entirely distinct thickness and temperature dependencies resulted in complicated damping behavior. The behavior of {\...
2302.06099v3
2023-09-15
On the formation of singularities for the slightly supercritical NLS equation with nonlinear damping
We consider the focusing, mass-supercritical NLS equation augmented with a nonlinear damping term. We provide sufficient conditions on the nonlinearity exponents and damping coefficients for finite-time blow-up. In particular, singularities are formed for focusing and dissipative nonlinearities of the same power, provi...
2309.08281v1
1998-05-07
Discovery of z=0.0912 and z=0.2212 Damped Lyman-alpha Absorption Line Systems Toward the Quasar OI 363: Limits on the Nature of Damped Lyman-alpha Galaxies
The discovery of a z_abs = 0.0912 damped Lyman-alpha absorption-line system in the HST-FOS ultraviolet spectrum of the quasar OI 363 (0738+313) is reported. This is the lowest redshift quasar damped Lyman-alpha system known. Its neutral hydrogen column density is N(HI) = 1.5(+/- 0.2) E21 atoms/cm^2, which easily exceed...
9805093v1
2008-01-24
Attenuation of small-amplitude oscillations in a prominence-corona model with a transverse magnetic field
Small-amplitude prominence oscillations are usually damped after a few periods. We study the attenuation of non-adiabatic magnetoacoustic waves in a slab prominence embedded in the coronal medium. We assume an equilibrium configuration with a transverse magnetic field to the slab axis and investigate wave damping by th...
0801.3744v2
2010-04-26
Selective spatial damping of propagating kink waves due to resonant absorption
There is observational evidence of propagating kink waves driven by photospheric motions. These disturbances, interpreted as kink magnetohydrodynamic (MHD) waves are attenuated as they propagate upwards in the solar corona. In this paper we show that resonant absorption provides a simple explanation to the spatial damp...
1004.4468v1
2011-04-10
Spatial Damping of Propagating Kink Waves Due to Resonant Absorption: Effect of Background Flow
Observations show the ubiquitous presence of propagating magnetohydrodynamic (MHD) kink waves in the solar atmosphere. Waves and flows are often observed simultaneously. Due to plasma inhomogeneity in the perpendicular direction to the magnetic field, kink waves are spatially damped by resonant absorption. The presence...
1104.1791v1
2013-02-08
On the Damping-Induced Self-Recovery Phenomenon in Mechanical Systems with Several Unactuated Cyclic Variables
The damping-induced self-recovery phenomenon refers to the fundamental property of underactuated mechanical systems: if an unactuated cyclic variable is under a viscous damping-like force and the system starts from rest, then the cyclic variable will always move back to its initial condition as the actuated variables c...
1302.2109v1
2016-07-06
Damping of Alfven waves by Turbulence and its Consequences: from Cosmic-Rays Streaming to Launching Winds
This paper considers turbulent damping of Alfven waves in magnetized plasmas. We identify two cases of damping, one related to damping of cosmic rays streaming instability, the other related to damping of Alfven waves emitted by a macroscopic wave source, e.g. stellar atmosphere. The physical difference between the two...
1607.02042v1
2018-01-18
Quantum Landau damping in dipolar Bose-Einstein condensates
We consider Landau damping of elementary excitations in Bose-Einstein condensates (BECs) with dipolar interactions. We discuss quantum and quasi-classical regimes of Landau damping. We use a generalized wave-kinetic description of BECs which, apart from the long range dipolar interactions, also takes into account the q...
1801.06256v1
2019-02-26
Enhanced Gilbert Damping in Re doped FeCo Films: A Combined Experimental and Theoretical Study
The effects of rhenium doping in the range 0 to 10 atomic percent on the static and dynamic magnetic properties of Fe65Co35 thin films have been studied experimentally as well as with first principles electronic structure calculations focusing on the change of the saturation magnetization and the Gilbert damping parame...
1902.09896v1
2020-05-31
Optimal decay rates of the compressible Euler equations with time-dependent damping in $\mathbb R^n$: (I) under-damping case
This paper is concerned with the multi-dimensional compressible Euler equations with time-dependent damping of the form $-\frac{\mu}{(1+t)^\lambda}\rho\boldsymbol u$ in $\mathbb R^n$, where $n\ge2$, $\mu>0$, and $\lambda\in[0,1)$. When $\lambda>0$ is bigger, the damping effect time-asymptotically gets weaker, which is ...
2006.00401v1
2022-08-17
Anti-parity-time symmetry hidden in a damping linear resonator
Phase transition from the over-damping to under-damping states is a ubiquitous phenomenon in physical systems. However, what kind of symmetry is broken associated with this phase transition remains unclear. Here, we discover that this phase transition is determined by an anti-parity-time (anti-$\mathcal{PT}$) symmetry ...
2208.08187v2
1996-12-10
Collisional matter-phase damping in Bose-condensed gas
Collisional damping of the excitations in a Bose-condensed gas is investigated over the wide range of energies and temperatures. Numerical results for the damping rate are presented and a number of asymptotic and interpolating expressions for it are derived.
9612086v1
2001-11-29
Tensor form of magnetization damping
A tensor form of phenomenological damping is derived for small magnetization motions. This form reflects basic physical relaxation processes for a general uniformly magnetized particle or film. Scalar Landau-Lifshitz damping is found to occur only for two special cases of system symmetry.
0111566v1
1999-07-28
An effective relaxation-time approach to collisionless quark-gluon plasma
We present an effective relaxation-time theory to study the collisionless quark-gluon plasma. Applying this method we calculate the damping rate to be of order $g^2T$ and find plasmon scattering is the damping mechanism. The damping for the transverse mode is stronger than the longitudinal one.
9907526v1
1999-11-16
Dynamical resummation and damping in the O(N) model
A general real-time formalism is developed to resum the self-energy operator of broken symmetry scalar field theories in form of self-consistent gap equations for the spectral function. The solution of the equations is approximated with finite lifetime quasi-particles. In the Landau damping rates viscosity terms, analo...
9911374v1
1993-03-24
On the Quantizations of the Damped Systems
Based on a simple observation that a classical second order differential equation may be decomposed into a set of two first order equations, we introduce a Hamiltonian framework to quantize the damped systems. In particular, we analyze the system of a linear damped harmonic oscillator and demonstrate that the time evol...
9303137v1
2006-01-09
Energy decay for damped wave equations on partially rectangular domains
We consider the wave equation with a damping term on a partially rectangular planar domain, assuming that the damping is concentrated close to the non-rectangular part of the domain. Polynomial decay estimates for the energy of the solution are established.
0601195v1
2002-06-07
Resonant states and classical damping
Using Koopman's approach to classical dynamical systems we show that the classical damping may be interpreted as appearance of resonant states of the corresponding Koopman's operator. It turns out that simple classical damped systems give rise to discrete complex spectra. Therefore, the corresponding generalized eigenv...
0206009v1
2004-03-12
Factorization of damped wave equations with cubic nonlinearities
The recent factorization scheme that we introduced for nonlinear polynomial ODEs in math-ph/0401040 is applied to the interesting case of damped wave equations with cubic nonlinearities. Traveling kink solutions are possible in the plane defined by the kink velocity versus the damping coefficient only along hyperbolas ...
0403022v1
2002-08-07
Toward a Universal Model of Damping--Modified Coulomb Friction
A modification of Coulomb's law of friction uses a variable coefficient of friction that depends on a power law in the energy of mechanical oscillation. Through the use of three different exponents: 0, 1/2 and 1; all commonly encountered non-viscous forms of damping are accommodated. The nonlinear model appears to yiel...
0208025v1
2002-12-19
Trapped particle bounds on stimulated scatter in the large k/kD regime
In the strongly damped regime, the convective gain rate for stimulated scatter varies inversely with the plasma wave damping rate. Electron trapping effects reduce the damping but also lead to loss of resonance for large enough amplitude waves. This leads to a gain rate bound and corresponding optimum scattered light f...
0212071v1
2003-02-03
Oscillator damping with more than one mechanism of internal friction dissipation
The author's modified Coulomb damping model has been generalized to accommodate internal friction that derives from several dissipation mechanisms acting simultaneously. Because of its fundamental nonlinear nature, internal friction damping causes the quality factor Q of an oscillator in free-decay to change in time. E...
0302003v1
2003-02-15
Anisotropic Internal Friction Damping
The mechanical damping properties of sheet polaroid material have been studied with a physical pendulum. The polaroid samples were placed under the knife-edges of the pendulum, which was operated in free-decay at a period in the vicinity of 10 s. With the edges oriented parallel to the direction of the long molecular c...
0302055v1
2006-08-07
Study of the Damped Pendulum
Experiments on the oscillatory motion of a suspended bar magnet throws light on the damping effects acting on the pendulum. The viscous drag offered by air was found the be the main contributor for slowing the pendulum down. The nature and magnitude of the damping effects were shown to be strongly dependent on the ampl...
0608071v1
1995-02-27
Quantum Oscillator with Kronig-Penney Excitation in Different Regimes of Damping
There are discussed the exact solution of the time--dependent Schr\"{o}dinger equation for a damped quantum oscillator subject to a periodical frequency delta--kicks describing squeezed states which are expressed in terms of Chebyshev polynomials. The cases of strong and weak damping are investigated in the frame of Ca...
9502023v1
2008-11-07
Asymptotic stability of the wave equation on compact surfaces and locally distributed damping - A sharp result
This paper is concerned with the study of the wave equation on compact surfaces and locally distributed damping. We study the case where the damping is effective in a well-chosen subset of arbitrarily small measure.
0811.1190v1
2008-11-07
Uniform Stabilization of the wave equation on compact surfaces and locally distributed damping
This paper is concerned with the study of the wave equation on compact surfaces and locally distributed damping. We study the case where the damping is effective on the complement of visible umbilical sets.
0811.1204v1
2010-11-20
Enhanced damping of ion acoustic waves in dense plasmas
A theory for the ion acoustic wave damping in dense plasmas and warm dense matter, accounting for the Umklapp process, is presented. A higher decay rate compared to the prediction from the Landau damping theory is predicted for high-Z dense plasmas where the electron density ranges from $10^{21}$ to $ 10^{24} \mathrm{c...
1011.4607v1
2012-05-16
Enhanced coupling design of a detuned damped structure for clic
The key feature of the improved coupling design in the Damped Detuned Structure (DDS) is focused on the four manifolds. Rectangular geometry slots and rectangular manifolds are used. This results in a significantly stronger coupling to the manifolds compared to the previous design. We describe the new design together w...
1205.3590v1
2012-06-26
On the $L^{2}$-critical nonlinear Schrödinger Equation with a nonlinear damping
We consider the Cauchy problem for the $L^{2}$-critical nonlinear Schr\"{o}dinger equation with a nonlinear damping. According to the power of the damping term, we prove the global existence or the existence of finite time blowup dynamics with the log-log blow-up speed for $\|\nabla u(t)\|_{L^2}$.
1206.6082v4
2012-10-12
Semi-linear wave equations with effective damping
We study the Cauchy problem for the semi-linear damped wave equation in any space dimension. We assume that the time-dependent damping term is effective. We prove the global existence of small energy data solutions in the supercritical case.
1210.3493v1
2012-12-08
A note on the lifespan of solutions to the semilinear damped wave equation
This paper concerns estimates of the lifespan of solutions to the semilinear damped wave equation. We give upper estimates of the lifespan for the semilinear damped wave equation with variable coefficients in all space dimensions.
1212.1772v3
2012-12-10
Strongly damped wave equation with exponential nonlinearities
In this paper, we study the initial boundary value problem for the two dimensional strong damped wave equation with exponentially growing source and damping terms. We first show the well-posedness of this problem and then prove the existence of the global attractor in $(H_{0}^{1}(\Omega)\cap L^{\infty}(\Omega))\times L...
1212.2180v2
2013-10-27
Exponential decay of solutions for the plate equation with localized damping
In this paper, we give positive answer to the open question raised in [E. Zuazua, Exponential decay for the semilinear wave equation with localized damping in unbounded domains. J. Math. Pures Appl., 70 (1991) 513--529] on the exponential decay of solutions for the semilinear plate equation with localized damping.
1310.7243v3
2014-03-07
Landau damping in Sobolev spaces for the Vlasov-HMF model
We consider the Vlasov-HMF (Hamiltonian Mean-Field) model. We consider solutions starting in a small Sobolev neighborhood of a spatially homogeneous state satisfying a linearized stability criterion (Penrose criterion). We prove that these solutions exhibit a scattering behavior to a modified state, which implies a non...
1403.1668v2
2015-03-30
Damping to prevent the blow-up of the Korteweg-de Vries equation
We study the behavior of the solution of a generalized damped KdV equation $u_t + u_x + u_{xxx} + u^p u_x + \mathscr{L}_{\gamma}(u)= 0$. We first state results on the local well-posedness. Then when $p \geq 4$, conditions on $\mathscr{L}_{\gamma}$ are given to prevent the blow-up of the solution. Finally, we numericall...
1503.08559v1
2015-06-16
Fast energy decay for wave equations with variable damping coefficients in the 1-D half line
We derive fast decay estimates of the total energy for wave equations with localized variable damping coefficients, which are dealt with in the one dimensional half line $(0,\infty)$. The variable damping coefficient vanishes near the boundary $x = 0$, and is effective critically near spatial infinity $x = \infty$.
1506.04851v1