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2019-11-05
Exceptional points in dissipatively coupled spin dynamics
We theoretically investigate dynamics of classical spins exchange-coupled through an isotropic medium. The coupling is treated at the adiabatic level of the medium's response, which mediates a first-order in frequency dissipative interaction along with an instantaneous Heisenberg exchange. The resultant damped spin pre...
1911.01619v2
2019-11-08
Influence of Sensor Feedback Limitations on Power Oscillation Damping and Transient Stability
Fundamental sensor feedback limitations for improving rotor angle stability using local frequency or phase angle measurement are derived. Using a two-machine power system model, it is shown that improved damping of inter-area oscillations must come at the cost of reduced transient stability margins, regardless of the c...
1911.03342v3
2019-11-12
Non-uniform Stability of Damped Contraction Semigroups
We investigate the stability properties of strongly continuous semigroups generated by operators of the form $A-BB^\ast$, where $A$ is a generator of a contraction semigroup and $B$ is a possibly unbounded operator. Such systems arise naturally in the study of hyperbolic partial differential equations with damping on t...
1911.04804v3
2020-01-31
Dynamo in weakly collisional nonmagnetized plasmas impeded by Landau damping of magnetic fields
We perform fully kinetic simulations of flows known to produce dynamo in magnetohydrodynamics (MHD), considering scenarios with low Reynolds number and high magnetic Prandtl number, relevant for galaxy cluster scale fluctuation dynamos. We find that Landau damping on the electrons leads to a rapid decay of magnetic per...
2001.11929v2
2020-03-05
Sound propagation and quantum limited damping in a two-dimensional Fermi gas
Strongly interacting two-dimensional Fermi systems are one of the great remaining challenges in many-body physics due to the interplay of strong local correlations and enhanced long-range fluctuations. Here, we probe the thermodynamic and transport properties of a 2D Fermi gas across the BEC-BCS crossover by studying t...
2003.02713v1
2020-03-09
Proof-of-principle direct measurement of Landau damping strength at the Large Hadron Collider with an anti-damper
Landau damping is an essential mechanism for ensuring collective beam stability in particle accelerators. Precise knowledge of how strong Landau damping is, is key to making accurate predictions on beam stability for state-of-the-art high energy colliders. In this paper we demonstrate an experimental procedure that wou...
2003.04383v1
2020-03-19
An inverse-system method for identification of damping rate functions in non-Markovian quantum systems
Identification of complicated quantum environments lies in the core of quantum engineering, which systematically constructs an environment model with the aim of accurate control of quantum systems. In this paper, we present an inverse-system method to identify damping rate functions which describe non-Markovian environ...
2003.08617v1
2020-04-23
Damping of gravitational waves in 2-2-holes
A 2-2-hole is an explicit realization of a horizonless object that can still very closely resemble a BH. An ordinary relativistic gas can serve as the matter source for the 2-2-hole solution of quadratic gravity, and this leads to a calculable area-law entropy. Here we show that it also leads to an estimate of the damp...
2004.11285v3
2020-05-04
Plasmon damping in electronically open systems
Rapid progress in electrically-controlled plasmonics in solids poses a question about effects of electronic reservoirs on the properties of plasmons. We find that plasmons in electronically open systems [i.e. in (semi)conductors connected to leads] are prone to an additional damping due to charge carrier penetration in...
2005.01680v1
2020-05-06
Helical damping and anomalous critical non-Hermitian skin effect
Non-Hermitian skin effect and critical skin effect are unique features of non-Hermitian systems. In this Letter, we study an open system with its dynamics of single-particle correlation function effectively dominated by a non-Hermitian damping matrix, which exhibits $\mathbb{Z}_2$ skin effect, and uncover the existence...
2005.02617v1
2020-05-16
Gravitational Landau Damping for massive scalar modes
We establish the possibility of Landau damping for gravitational scalar waves which propagate in a non-collisional gas of particles. In particular, under the hypothesis of homogeneity and isotropy, we describe the medium at the equilibrium with a J\"uttner-Maxwell distribution, and we analytically determine the damping...
2005.08010v4
2020-05-21
On Strong Feller Property, Exponential Ergodicity and Large Deviations Principle for Stochastic Damping Hamiltonian Systems with State-Dependent Switching
This work focuses on a class of stochastic damping Hamiltonian systems with state-dependent switching, where the switching process has a countably infinite state space. After establishing the existence and uniqueness of a global weak solution via the martingale approach under very mild conditions, the paper next proves...
2005.10730v1
2020-06-09
Logarithmic decay for damped hypoelliptic wave and Schr{ö}dinger equations
We consider damped wave (resp. Schr{\"o}dinger and plate) equations driven by a hypoelliptic "sum of squares" operator L on a compact manifold and a damping function b(x). We assume the Chow-Rashevski-H{\"o}rmander condition at rank k (at most k Lie brackets needed to span the tangent space) together with analyticity o...
2006.05122v1
2020-06-14
Bulk Viscous Damping of Density Oscillations in Neutron Star Mergers
In this paper, we discuss the damping of density oscillations in dense nuclear matter in the temperature range relevant to neutron star mergers. This damping is due to bulk viscosity arising from the weak interaction ``Urca'' processes of neutron decay and electron capture. The nuclear matter is modelled in the relativ...
2006.07975v2
2020-06-15
Exact solutions of a damped harmonic oscillator in a time dependent noncommutative space
In this paper we have obtained the exact eigenstates of a two dimensional damped harmonic oscillator in time dependent noncommutative space. It has been observed that for some specific choices of the damping factor and the time dependent frequency of the oscillator, there exists interesting solutions of the time depend...
2006.08611v1
2020-06-16
Enhancing nonlinear damping by parametric-direct internal resonance
Mechanical sources of nonlinear damping play a central role in modern physics, from solid-state physics to thermodynamics. The microscopic theory of mechanical dissipation [M. I . Dykman, M. A. Krivoglaz, Physica Status Solidi (b) 68, 111 (1975)] suggests that nonlinear damping of a resonant mode can be strongly enhanc...
2006.09364v3
2020-06-22
Blow-up for wave equation with the scale-invariant damping and combined nonlinearities
In this article, we study the blow-up of the damped wave equation in the \textit{scale-invariant case} and in the presence of two nonlinearities. More precisely, we consider the following equation: $$u_{tt}-\Delta u+\frac{\mu}{1+t}u_t=|u_t|^p+|u|^q, \quad \mbox{in}\ \R^N\times[0,\infty), $$ with small initial data.\\ F...
2006.12600v1
2020-07-10
Decentralized Frequency Control using Packet-based Energy Coordination
This paper presents a novel frequency-responsive control scheme for demand-side resources, such as electric water heaters. A frequency-dependent control law is designed to provide damping from distributed energy resources (DERs) in a fully decentralized fashion. This local control policy represents a frequency-dependen...
2007.05624v1
2020-07-30
Origin of micron-scale propagation lengths of heat-carrying acoustic excitations in amorphous silicon
The heat-carrying acoustic excitations of amorphous silicon are of interest because their mean free paths may approach micron scales at room temperature. Despite extensive investigation, the origin of the weak acoustic damping in the heat-carrying frequencies remains a topic of debate. Here, we report measurements of t...
2007.15777v2
2020-08-06
Quantum sensing of open systems: Estimation of damping constants and temperature
We determine quantum precision limits for estimation of damping constants and temperature of lossy bosonic channels. A direct application would be the use of light for estimation of the absorption and the temperature of a transparent slab. Analytic lower bounds are obtained for the uncertainty in the estimation, throug...
2008.02728v1
2020-08-07
Quantifying the evidence for resonant damping of coronal waves with foot-point wave power asymmetry
We use Coronal Multi-channel Polarimeter (CoMP) observations of propagating waves in the solar corona and Bayesian analysis to assess the evidence of models with resonant damping and foot-point wave power asymmetries. Two nested models are considered. The reduced model considers resonant damping as the sole cause of th...
2008.03004v1
2020-08-22
Sound damping in frictionless granular materials: The interplay between configurational disorder and inelasticity
We numerically investigate sound damping in a model of granular materials in two dimensions. We simulate evolution of standing waves in disordered frictionless disks and analyze their damped oscillations by velocity autocorrelation functions and power spectra. We control the strength of inelastic interactions between t...
2008.09760v1
2020-09-27
Squeezed comb states
Continuous-variable codes are an expedient solution for quantum information processing and quantum communication involving optical networks. Here we characterize the squeezed comb, a finite superposition of equidistant squeezed coherent states on a line, and its properties as a continuous-variable encoding choice for a...
2009.12888v2
2020-11-16
Switchable Damping for a One-Particle Oscillator
The possibility to switch the damping rate for a one-electron oscillator is demonstrated, for an electron that oscillates along the magnetic field axis in a Penning trap. Strong axial damping can be switched on to allow this oscillation to be used for quantum nondemolition detection of the cyclotron and spin quantum st...
2011.08136v2
2020-11-15
A Random Matrix Theory Approach to Damping in Deep Learning
We conjecture that the inherent difference in generalisation between adaptive and non-adaptive gradient methods in deep learning stems from the increased estimation noise in the flattest directions of the true loss surface. We demonstrate that typical schedules used for adaptive methods (with low numerical stability or...
2011.08181v5
2020-11-17
Challenging an experimental nonlinear modal analysis method with a new strongly friction-damped structure
In this work, we show that a recently proposed method for experimental nonlinear modal analysis based on the extended periodic motion concept is well suited to extract modal properties for strongly nonlinear systems (i.e. in the presence of large frequency shifts, high and nonlinear damping, changes of the mode shape, ...
2011.08527v1
2020-11-27
Thermal damping of Weak Magnetosonic Turbulence in the Interstellar Medium
We present a generic mechanism for the thermal damping of compressive waves in the interstellar medium (ISM), occurring due to radiative cooling. We solve for the dispersion relation of magnetosonic waves in a two-fluid (ion-neutral) system in which density- and temperature-dependent heating and cooling mechanisms are ...
2011.13879v3
2021-02-10
WAMS-Based Model-Free Wide-Area Damping Control by Voltage Source Converters
In this paper, a novel model-free wide-area damping control (WADC) method is proposed, which can achieve full decoupling of modes and damp multiple critical inter-area oscillations simultaneously using grid-connected voltage source converters (VSCs). The proposed method is purely measurement based and requires no knowl...
2102.05494v1
2021-04-08
Fast optimization of viscosities for frequency-weighted damping of second-order systems
We consider frequency-weighted damping optimization for vibrating systems described by a second-order differential equation. The goal is to determine viscosity values such that eigenvalues are kept away from certain undesirable areas on the imaginary axis. To this end, we present two complementary techniques. First, we...
2104.04035v1
2021-04-09
Nonexistence result for the generalized Tricomi equation with the scale-invariant damping, mass term and time derivative nonlinearity
In this article, we consider the damped wave equation in the \textit{scale-invariant case} with time-dependent speed of propagation, mass term and time derivative nonlinearity. More precisely, we study the blow-up of the solutions to the following equation: $$ (E) \quad u_{tt}-t^{2m}\Delta u+\frac{\mu}{t}u_t+\frac{\nu^...
2104.04393v2
2021-04-12
Slow periodic oscillation without radiation damping: New evolution laws for rate and state friction
The dynamics of sliding friction is mainly governed by the frictional force. Previous studies have shown that the laboratory-scale friction is well described by an empirical law stated in terms of the slip velocity and the state variable. The state variable represents the detailed physicochemical state of the sliding i...
2104.05398v2
2021-04-27
Absence of a boson peak in anharmonic phonon models with Akhiezer-type damping
In a recent article M. Baggioli and A. Zaccone (Phys. Rev. Lett. {\bf 112}, 145501 (2019)) claimed that an anharmonic damping, leading to a sound attenuation proportional to $\omega^2$ (Akhiezer-type damping) would imply a boson peak, i.e.\ a maximum in the vibrational density of states, divided by the frequency square...
2104.13076v1
2021-05-03
Damping and polarization rates in near equilibrium state
The collision terms in spin transport theory are analyzed in Kadanoff-Baym formalism for systems close to equilibrium. The non-equilibrium fluctuations in spin distribution include both damping and polarization, with the latter arising from the exchange between orbital and spin angular momenta. The damping and polariza...
2105.00915v1
2021-06-07
Voltage-control of damping constant in magnetic-insulator/topological-insulator bilayers
The magnetic damping constant is a critical parameter for magnetization dynamics and the efficiency of memory devices and magnon transport. Therefore, its manipulation by electric fields is crucial in spintronics. Here, we theoretically demonstrate the voltage-control of magnetic damping in ferro- and ferrimagnetic-ins...
2106.03332v1
2021-05-14
Exact solution of damped harmonic oscillator with a magnetic field in a time dependent noncommutative space
In this paper we have obtained the exact eigenstates of a two dimensional damped harmonic oscillator in the presence of an external magnetic field varying with respect to time in time dependent noncommutative space. It has been observed that for some specific choices of the damping factor, the time dependent frequency ...
2106.05182v1
2021-06-21
Self-stabilization of light sails by damped internal degrees of freedom
We consider the motion of a light sail that is accelerated by a powerful laser beam. We derive the equations of motion for two proof-of-concept sail designs with damped internal degrees of freedom. Using linear stability analysis we show that perturbations of the sail movement in all lateral degrees of freedom can be d...
2106.10961v1
2021-07-14
Determining the source of phase noise: Response of a driven Duffing oscillator to low-frequency damping and resonance frequency fluctuations
We present an analytical calculation of the response of a driven Duffing oscillator to low-frequency fluctuations in the resonance frequency and damping. We find that fluctuations in these parameters manifest themselves distinctively, allowing them to be distinguished. In the strongly nonlinear regime, amplitude and ph...
2107.06879v1
2021-07-27
Spin transport-induced damping of coherent THz spin dynamics in iron
We study the damping of perpendicular standing spin-waves (PSSWs) in ultrathin Fe films at frequencies up to 2.4 THz. The PSSWs are excited by optically generated ultrashort spin current pulses, and probed optically in the time domain. Analyzing the wavenumber and thickness dependence of the damping, we demonstrate tha...
2107.12812v2
2021-07-29
A N-dimensional elastic\viscoelastic transmission problem with Kelvin-Voigt damping and non smooth coefficient at the interface
We investigate the stabilization of a multidimensional system of coupled wave equations with only one Kelvin Voigt damping. Using a unique continuation result based on a Carleman estimate and a general criteria of Arendt Batty, we prove the strong stability of the system in the absence of the compactness of the resolve...
2107.13785v1
2021-09-03
Stabilization of the damped plate equation under general boundary conditions
We consider a damped plate equation on an open bounded subset of R^d, or a smooth manifold, with boundary, along with general boundary operators fulfilling the Lopatinskii-Sapiro condition. The damping term acts on a region without imposing a geometrical condition. We derive a resolvent estimate for the generator of th...
2109.01521v2
2021-09-07
Fluid energy cascade rate and kinetic damping: new insight from 3D Landau-fluid simulations
Using an exact law for incompressible Hall magnetohydrodynamics (HMHD) turbulence, the energy cascade rate is computed from three-dimensional HMHD-CGL (bi-adiabatic ions and isothermal electrons) and Landau fluid (LF) numerical simulations that feature different intensities of Landau damping over a broad range of waven...
2109.03123v2
2021-09-24
Effect of nonlocal transformations on the linearizability and exact solvability of the nonlinear generalized modified Emden type equations
The nonlinear generalized modified Emden type equations (GMEE) are known to be linearizable into simple harmonic oscillator (HO) or damped harmonic oscillators (DHO) via some nonlocal transformations. Hereby, we show that the structure of the nonlocal transformation and the linearizability into HO or DHO determine the ...
2109.12059v1
2021-12-27
Trajectory attractors for 3D damped Euler equations and their approximation
We study the global attractors for the damped 3D Euler--Bardina equations with the regularization parameter $\alpha>0$ and Ekman damping coefficient $\gamma>0$ endowed with periodic boundary conditions as well as their damped Euler limit $\alpha\to0$. We prove that despite the possible non-uniqueness of solutions of th...
2112.13691v1
2022-01-12
Implicit Bias of MSE Gradient Optimization in Underparameterized Neural Networks
We study the dynamics of a neural network in function space when optimizing the mean squared error via gradient flow. We show that in the underparameterized regime the network learns eigenfunctions of an integral operator $T_{K^\infty}$ determined by the Neural Tangent Kernel (NTK) at rates corresponding to their eigen...
2201.04738v1
2022-01-19
Variance-Reduced Stochastic Quasi-Newton Methods for Decentralized Learning: Part II
In Part I of this work, we have proposed a general framework of decentralized stochastic quasi-Newton methods, which converge linearly to the optimal solution under the assumption that the local Hessian inverse approximations have bounded positive eigenvalues. In Part II, we specify two fully decentralized stochastic q...
2201.07733v1
2022-01-19
Active tuning of plasmon damping via light induced magnetism
Circularly polarized optical excitation of plasmonic nanostructures causes coherent circulating motion of their electrons, which in turn, gives rise to strong optically induced magnetization - a phenomenon known as the inverse Faraday effect (IFE). In this study we report how the IFE also significantly decreases plasmo...
2201.07842v1
2022-03-02
Simplified Stability Assessment of Power Systems with Variable-Delay Wide-Area Damping Control
Power electronic devices such as HVDC and FACTS can be used to improve the damping of poorly damped inter-area modes in large power systems. This involves the use of wide-area feedback signals, which are transmitted via communication networks. The performance of the closed-loop system is strongly influenced by the dela...
2203.01362v1
2022-03-03
Forward-modulated damping estimates and nonlocalized stability of periodic Lugiato-Lefever wave
In an interesting recent analysis, Haragus-Johnson-Perkins-de Rijk have shown modulational stability under localized perturbations of steady periodic solutions of the Lugiato-Lefever equation (LLE), in the process pointing out a difficulty in obtaining standard "nonlinear damping estimates" on modulated perturbation va...
2203.01770v3
2022-03-31
Observing Particle Energization above the Nyquist Frequency: An Application of the Field-Particle Correlation Technique
The field-particle correlation technique utilizes single-point measurements to uncover signatures of various particle energization mechanisms in turbulent space plasmas. The signature of Landau damping by electrons has been found in both simulations and observations from Earth's magnetosheath using this technique, but ...
2204.00104v1
2022-04-06
A Potential Based Quantization Procedure of the Damped Oscillator
Nowadays, two of the most prospering fields of physics are quantum computing and spintronics. In both, the loss of information and dissipation plays a crucial role. In the present work we formulate the quantization of the dissipative oscillator, which aids understanding of the above mentioned, and creates a theoretical...
2204.02893v2
2022-04-19
Role of shape anisotropy on thermal gradient-driven domain wall dynamics in magnetic nanowires
We investigate the magnetic domain wall (DW) dynamics in uniaxial/biaxial nanowires under a thermal gradient (TG). The findings reveal that the DW propagates toward the hotter region in both nanowires. The main physics of such observations is the magnonic angular momentum transfer to the DW. The hard (shape) anisotropy...
2204.09101v2
2022-04-25
Energy decay estimates for the wave equation with supercritical nonlinear damping
We consider a damped wave equation in a bounded domain. The damping is nonlinear and is homogeneous with degree p -- 1 with p > 2. First, we show that the energy of the strong solution in the supercritical case decays as a negative power of t; the rate of decay is the same as in the subcritical or critical cases, provi...
2204.11494v1
2022-05-07
Proposal for a Damping-Ring-Free Electron Injector for Future Linear Colliders
The current designs of future electron-positron linear colliders incorporate large and complex damping rings to produce asymmetric beams for beamstrahlung suppression. Here we present the design of an electron injector capable of delivering flat electron beams with phase-space partition comparable to the electron-beam ...
2205.03736v1
2022-06-02
Optimal Control of the 3D Damped Navier-Stokes-Voigt Equations with Control Constraints
In this paper, we consider the 3D Navier-Stokes-Voigt (NSV) equations with nonlinear damping $|u|^{r-1}u, r\in[1,\infty)$ in bounded and space-periodic domains. We formulate an optimal control problem of minimizing the curl of the velocity field in the energy norm subject to the flow velocity satisfying the damped NSV ...
2206.00988v2
2022-06-05
Stationary measures for stochastic differential equations with degenerate damping
A variety of physical phenomena involve the nonlinear transfer of energy from weakly damped modes subjected to external forcing to other modes which are more heavily damped. In this work we explore this in (finite-dimensional) stochastic differential equations in $\mathbb R^n$ with a quadratic, conservative nonlinearit...
2206.02240v1
2022-06-17
Resolvent estimates for the one-dimensional damped wave equation with unbounded damping
We study the generator $G$ of the one-dimensional damped wave equation with unbounded damping. We show that the norm of the corresponding resolvent operator, $\| (G - \lambda)^{-1} \|$, is approximately constant as $|\lambda| \to +\infty$ on vertical strips of bounded width contained in the closure of the left-hand sid...
2206.08820v2
2022-07-13
Energy decay for the time dependent damped wave equation
Energy decay is established for the damped wave equation on compact Riemannian manifolds where the damping coefficient is allowed to depend on time. Using a time dependent observability inequality, it is shown that the energy of solutions decays at an exponential rate if the damping coefficient satisfies a time depende...
2207.06260v4
2022-08-04
Lp-asymptotic stability of 1D damped wave equations with localized and nonlinear damping
In this paper, we study the $L^p$-asymptotic stability with $p\in (1,\infty)$ of the one-dimensional nonlinear damped wave equation with a localized damping and Dirichlet boundary conditions in a bounded domain $(0,1)$. We start by addressing the well-posedness problem. We prove the existence and the uniqueness of weak...
2208.02779v1
2022-08-07
Damping of neutrino oscillations, decoherence and the lengths of neutrino wave packets
Spatial separation of the wave packets (WPs) of neutrino mass eigenstates leads to decoherence and damping of neutrino oscillations. Damping can also be caused by finite energy resolution of neutrino detectors or, in the case of experiments with radioactive neutrino sources, by finite width of the emitted neutrino line...
2208.03736v2
2022-08-23
Fate of exceptional points in the presence of nonlinearities
The non-Hermitian dynamics of open systems deal with how intricate coherent effects of a closed system intertwine with the impact of coupling to an environment. The system-environment dynamics can then lead to so-called exceptional points, which are the open-system marker of phase transitions, i.e., the closing of spec...
2208.11205v2
2022-09-10
Data-driven, multi-moment fluid modeling of Landau damping
Deriving governing equations of complex physical systems based on first principles can be quite challenging when there are certain unknown terms and hidden physical mechanisms in the systems. In this work, we apply a deep learning architecture to learn fluid partial differential equations (PDEs) of a plasma system base...
2209.04726v1
2022-09-25
Formation of the cosmic-ray halo: The role of nonlinear Landau damping
We present a nonlinear model of self-consistent Galactic halo, where the processes of cosmic ray (CR) propagation and excitation/damping of MHD waves are included. The MHD-turbulence, which prevents CR escape from the Galaxy, is entirely generated by the resonant streaming instability. The key mechanism controlling the...
2209.12302v1
2022-10-10
Finite time extinction for a critically damped Schr{ö}dinger equation with a sublinear nonlinearity
This paper completes some previous studies by several authors on the finite time extinction for nonlinear Schr{\"o}dinger equation when the nonlinear damping term corresponds to the limit cases of some ``saturating non-Kerr law'' $F(|u|^2)u=\frac{a}{\varepsilon+(|u|^2)^\alpha}u,$ with $a\in\mathbb{C},$ $\varepsilon\geq...
2210.04493v4
2022-10-14
Landau damping for gravitational waves in parity-violating theories
We discuss how tensor polarizations of gravitational waves can suffer Landau damping in the presence of velocity birefringence, when parity symmetry is explicitly broken. In particular, we analyze the role of the Nieh-Yan and Chern-Simons terms in modified theories of gravity, showing how the gravitational perturbation...
2210.07673v2
2022-10-25
Formation of shifted shock for the 3D compressible Euler equations with damping
In this paper, we show the shock formation of the solutions to the 3-dimensional (3D) compressible isentropic and irrotational Euler equations with damping for the initial short pulse data which was first introduced by D.Christodoulou\cite{christodoulou2007}. Due to the damping effect, the largeness of the initial data...
2210.13796v1
2022-10-30
Dynamics of a class of extensible beams with degenerate and non-degenerate nonlocal damping
This work is concerned with new results on long-time dynamics of a class of hyperbolic evolution equations related to extensible beams with three distinguished nonlocal nonlinear damping terms. In the first possibly degenerate case, the results feature the existence of a family of compact global attractors and a thickn...
2210.16851v1
2022-11-11
Nonlinear fractional damped wave equation on compact Lie groups
In this paper, we deal with the initial value fractional damped wave equation on $G$, a compact Lie group, with power-type nonlinearity. The aim of this manuscript is twofold. First, using the Fourier analysis on compact Lie groups, we prove a local in-time existence result in the energy space for the fractional damped...
2211.06155v1
2022-11-16
Controlling the motional quality factor of a diamagnetically levitated graphite plate
Researchers seek methods to levitate matter for a wide variety of purposes, ranging from exploring fundamental problems in science, through to developing new sensors and mechanical actuators. Many levitation techniques require active driving and most can only be applied to objects smaller than a few micrometers. Diamag...
2211.08764v1
2022-12-03
Strong On-Chip Microwave Photon-Magnon Coupling Using Ultra-low Damping Epitaxial Y3Fe5O12 Films at 2 Kelvin
Y3Fe5O12 is arguably the best magnetic material for magnonic quantum information science (QIS) because of its extremely low damping. We report ultralow damping at 2 K in epitaxial Y3Fe5O12 thin films grown on a diamagnetic Y3Sc2Ga3O12 substrate that contains no rare-earth elements. Using these ultralow damping YIG film...
2212.01708v1
2022-12-21
Fractional damping effects on the transient dynamics of the Duffing oscillator
We consider the nonlinear Duffing oscillator in presence of fractional damping which is characteristic in different physical situations. The system is studied with a smaller and larger damping parameter value, that we call the underdamped and overdamped regimes. In both we have studied the relation between the fraction...
2212.11023v1
2023-01-02
Fast convex optimization via closed-loop time scaling of gradient dynamics
In a Hilbert setting, for convex differentiable optimization, we develop a general framework for adaptive accelerated gradient methods. They are based on damped inertial dynamics where the coefficients are designed in a closed-loop way. Specifically, the damping is a feedback control of the velocity, or of the gradient...
2301.00701v1
2023-01-19
Damped harmonic oscillator revisited: the fastest route to equilibrium
Theoretically, solutions of the damped harmonic oscillator asymptotically approach equilibrium, i.e., the zero energy state, without ever reaching it exactly, and the critically damped solution approaches equilibrium faster than the underdamped or the overdamped solution. Experimentally, the systems described with this...
2301.08222v2
2023-01-22
Boundary stabilization of a vibrating string with variable length
We study small vibrations of a string with time-dependent length $\ell(t)$ and boundary damping. The vibrations are described by a 1-d wave equation in an interval with one moving endpoint at a speed $\ell'(t)$ slower than the speed of propagation of the wave c=1. With no damping, the energy of the solution decays if t...
2301.09086v1
2023-02-24
Asymptotic behaviour of the semidiscrete FE approximations to weakly damped wave equations with minimal smoothness on initial data
Exponential decay estimates of a general linear weakly damped wave equation are studied with decay rate lying in a range. Based on the $C^0$-conforming finite element method to discretize spatial variables keeping temporal variable continuous, a semidiscrete system is analysed, and uniform decay estimates are derived w...
2302.12476v1
2023-02-27
Nonlinear acoustic imaging with damping
In this paper, we consider an inverse problem for a nonlinear wave equation with a damping term and a general nonlinear term. This problem arises in nonlinear acoustic imaging and has applications in medical imaging and other fields. The propagation of ultrasound waves can be modeled by a quasilinear wave equation with...
2302.14174v1
2023-04-11
Sizable suppression of magnon Hall effect by magnon damping in Cr$_2$Ge$_2$Te$_6$
Two-dimensional (2D) Heisenberg honeycomb ferromagnets are expected to have interesting topological magnon effects as their magnon dispersion can have Dirac points. The Dirac points are gapped with finite second nearest neighbor Dzyaloshinskii-Moriya interaction, providing nontrivial Berry curvature with finite magnon ...
2304.04922v1
2023-04-22
Video analysis of the damped oscillations of Pohl's pendulum
In this paper problems that arose with the introduction of distance learning in physics at the Technical University of Sofia due to the COVID-19 pandemic and the imposition of video recording of laboratory exercises are indicated. It was found that the video for the ''Damped Mechanical Oscillations'' exercise provides ...
2304.11390v1
2023-05-22
Semi-active damping optimization of vibrational systems using the reduced basis method
In this article, we consider vibrational systems with semi-active damping that are described by a second-order model. In order to minimize the influence of external inputs to the system response, we are optimizing some damping values. As minimization criterion, we evaluate the energy response, that is the $\cH_2$-norm ...
2305.12946v1
2023-06-01
A combined volume penalization / selective frequency damping approach for immersed boundary methods: application to moving geometries
This work extends, to moving geometries, the immersed boundary method based on volume penalization and selective frequency damping approach [J. Kou, E. Ferrer, A combined volume penalization/selective frequency damping approach for immersed boundary methods applied to high-order schemes, Journal of Computational Physic...
2306.00504v1
2023-06-09
Damped nonlinear Schrödinger equation with Stark effect
We study the $L^2$-critical damped NLS with a Stark potential. We prove that the threshold for global existence and finite time blowup of this equation is given by $\|Q\|_2$, where $Q$ is the unique positive radial solution of $\Delta Q + |Q|^{4/d} Q = Q$ in $H^1(\mathbb{R}^d)$. Moreover, in any small neighborhood of $...
2306.05931v1
2023-06-19
New Perspectives and Systematic Approaches for Analyzing Negative Damping-Induced Sustained Oscillation
Sustained oscillations (SOs) are commonly observed in systems dominated by converters. Under specific conditions, even though the origin of SOs can be identified through negative damping modes using conventional linear analysis, utilizing the describing function to compute harmonic amplitude and frequency remains incom...
2306.10839v2
2023-06-24
Numerical approximation of the invariant distribution for a class of stochastic damped wave equations
We study a class of stochastic semilinear damped wave equations driven by additive Wiener noise. Owing to the damping term, under appropriate conditions on the nonlinearity, the solution admits a unique invariant distribution. We apply semi-discrete and fully-discrete methods in order to approximate this invariant dist...
2306.13998v1
2023-07-31
Estimation of Power in the Controlled Quantum Teleportation through the Witness Operator
Controlled quantum teleportation (CQT) can be considered as a variant of quantum teleportation in which three parties are involved where one party acts as the controller. The usability of the CQT scheme depends on two types of fidelities viz. conditioned fidelity and non-conditioned fidelity. The difference between the...
2307.16574v1
2023-08-03
Triple-Spherical Bessel Function Integrals with Exponential and Gaussian Damping: Towards an Analytic N-Point Correlation Function Covariance Model
Spherical Bessel functions appear commonly in many areas of physics wherein there is both translation and rotation invariance, and often integrals over products of several arise. Thus, analytic evaluation of such integrals with different weighting functions (which appear as toy models of a given physical observable, su...
2308.01955v2
2023-08-28
Quantized damped transversal single particle mechanical waves
In information transfer, the dissipation of a signal may have crucial importance. The feasibility of reconstructing the distorted signal also depends on this. That is why the study of quantized dissipative transversal single particle mechanical waves may have an important role. It may be true, particularly on the nanos...
2308.14820v1
2023-11-15
Integrated Local Energy Decay for Damped Magnetic Wave Equations on Stationary Space-Times
We establish local energy decay for damped magnetic wave equations on stationary, asymptotically flat space-times subject to the geometric control condition. More specifically, we allow for the addition of time-independent magnetic and scalar potentials, which negatively affect energy coercivity and may add in unwieldy...
2311.08628v1
2023-11-15
Applications of $L^p-L^q$ estimates for solutions to semi-linear $σ$-evolution equations with general double damping
In this paper, we would like to study the linear Cauchy problems for semi-linear $\sigma$-evolution models with mixing a parabolic like damping term corresponding to $\sigma_1 \in [0,\sigma/2)$ and a $\sigma$-evolution like damping corresponding to $\sigma_2 \in (\sigma/2,\sigma]$. The main goals are on the one hand to...
2311.09085v1
2023-11-23
Friction of a driven chain: Role of momentum conservation, Goldstone and radiation modes
We analytically study friction and dissipation of a driven bead in a 1D harmonic chain, and analyze the role of internal damping mechanism as well as chain length. Specifically, we investigate Dissipative Particle Dynamics and Langevin Dynamics, as paradigmatic examples that do and do not display translational symmetry...
2311.14075v1
2023-12-07
Generalized Damping Torque Analysis of Ultra-Low Frequency Oscillation in the Jerk Space
Ultra low frequency oscillation (ULFO) is significantly threatening the power system stability. Its unstable mechanism is mostly studied via generalized damping torque analysis method (GDTA). However, the analysis still adopts the framework established for low frequency oscillation. Hence, this letter proposes a GDTA a...
2312.04148v1
2023-12-08
Selective damping of plasmons in coupled two-dimensional systems by Coulomb drag
The Coulomb drag is a many-body effect observed in proximized low-dimensional systems. It appears as emergence of voltage in one of them upon passage of bias current in another. The magnitude of drag voltage can be strongly affected by exchange of plasmonic excitations between the layers; however, the reverse effect of...
2312.05097v1
2023-12-13
Geometrical Interpretation of Neutrino Oscillation with decay
The geometrical representation of two-flavor neutrino oscillation represents the neutrino's flavor eigenstate as a magnetic moment-like vector that evolves around a magnetic field-like vector that depicts the Hamiltonian of the system. In the present work, we demonstrate the geometrical interpretation of neutrino in a ...
2312.08178v1
2023-12-14
Smoluchowski-Kramers diffusion approximation for systems of stochastic damped wave equations with non-constant friction
We consider systems of damped wave equations with a state-dependent damping coefficient and perturbed by a Gaussian multiplicative noise. Initially, we investigate their well-posedness, under quite general conditions on the friction. Subsequently, we study the validity of the so-called Smoluchowski-Kramers diffusion ap...
2312.08925v1
2023-12-28
Cause-effect relationship between model parameters and damping performance of hydraulic shock absorbers
Despite long-term research and development of modern shock absorbers, the effect of variations of several crucial material and model parameters still remains dubious. The goal of this work is therefore a study of the changes of shock absorber dynamics with respect to typical parameter ranges in a realistic model. We st...
2312.17175v1
2024-01-01
Magnon Damping Minimum and Logarithmic Scaling in a Kondo-Heisenberg Model
Recently, an anomalous temperature evolution of spin wave excitations has been observed in a van der Waals metallic ferromagnet Fe$_3$GeTe$_2$ (FGT) [S. Bao, et al., Phys. Rev. X 12, 011022 (2022)], whose theoretical understanding yet remains elusive. Here we study the spin dynamics of a ferromagnetic Kondo-Heisenberg ...
2401.00758v1
2024-01-04
Simplified Information Geometry Approach for Massive MIMO-OFDM Channel Estimation -- Part II: Convergence Analysis
In Part II of this two-part paper, we prove the convergence of the simplified information geometry approach (SIGA) proposed in Part I. For a general Bayesian inference problem, we first show that the iteration of the common second-order natural parameter (SONP) is separated from that of the common first-order natural p...
2401.02037v1
2024-01-04
A Pure Integral-Type PLL with a Damping Branch to Enhance the Stability of Grid-Tied Inverter under Weak Grids
In a phase-locked loop (PLL) synchronized inverter, due to the strong nonlinear coupling between the PLL's parame-ters and the operation power angle, the equivalent damping coefficient will quickly deteriorate while the power angle is close to 90{\deg} under an ultra-weak grid, which causes the synchronous instability....
2401.02202v1
2024-01-05
Solving convex optimization problems via a second order dynamical system with implicit Hessian damping and Tikhonov regularization
This paper deals with a second order dynamical system with a Tikhonov regularization term in connection to the minimization problem of a convex Fr\'echet differentiable function. The fact that beside the asymptotically vanishing damping we also consider an implicit Hessian driven damping in the dynamical system under s...
2401.02676v1
2024-01-16
Influence of temperature, doping, and amorphization on the electronic structure and magnetic damping of iron
Hybrid magnonic quantum systems have drawn increased attention in recent years for coherent quantum information processing, but too large magnetic damping is a persistent concern when metallic magnets are used. Their intrinsic damping is largely determined by electron-magnon scattering induced by spin-orbit interaction...
2401.08076v1
2024-01-16
Waves in strong centrifugal filed: dissipative gas
In the fast rotating gas (with the velocity typical for Iguassu gas centrifuge) three families of linear waves exist with different polarizations and law of dispersion. The energy of the waves is basically concentrated at the axis of rotation in the rarefied region. Therefore these waves decay on the distance comparabl...
2401.08240v1
2024-01-19
Upper bound of the lifespan of the solution to the nonlinear fractional wave equations with time-dependent damping
In this paper, we study the Cauchy problem of the nonlinear wave equation with fractional Laplacian and time-dependent damping. Firstly, we derive the weighted Sobolev estimate of the solution operators for the linear wave equation with the damping of constant coefficient, and prove the local existence and uniqueness i...
2401.10552v1