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2019-06-02
Mixed control of vibrational systems
We consider new performance measures for vibrational systems based on the $H_2$ norm of linear time invariant systems. New measures will be used as an optimization criterion for the optimal damping of vibrational systems. We consider both theoretical and concrete cases in order to show how new measures stack up against...
1906.00503v1
2019-06-27
Comments on the linear modified Poisson-Boltzmann equation in electrolyte solution theory
Three analytic results are proposed for a linear form of the modified Poisson-Boltzmann equation in the theory of bulk electrolytes. Comparison is also made with the mean spherical approximation results. The linear theories predict a transition of the mean electrostatic potential from a Debye-H\"{u}ckel type damped exp...
1906.11584v1
2019-09-19
Growth rate and gain of stimulated Brillouin scattering considering nonlinear Landau damping due to particle trapping
Growth rate and gain of SBS considering the reduced Landau damping due to particle trapping has been proposed to predict the growth and average level of SBS reflectivity. Due to particle trapping, the reduced Landau damping has been taken used of to calculate the gain of SBS, which will make the simulation data of SBS ...
1909.11606v1
2019-11-26
Pullback Attractors for a Critical Degenerate Wave Equation with Time-dependent Damping
The aim of this paper is to analyze the long-time dynamical behavior of the solution for a degenerate wave equation with time-dependent damping term $\partial_{tt}u + \beta(t)\partial_tu = \mathcal{L}u(x,t) + f(u)$ on a bounded domain $\Omega\subset\mathbb{R}^N$ with Dirichlet boundary conditions. Under some restrictio...
1911.11432v1
2019-12-18
Blow-up criteria for linearly damped nonlinear Schrödinger equations
We consider the Cauchy problem for linearly damped nonlinear Schr\"odinger equations \[ i\partial_t u + \Delta u + i a u= \pm |u|^\alpha u, \quad (t,x) \in [0,\infty) \times \mathbb{R}^N, \] where $a>0$ and $\alpha>0$. We prove the global existence and scattering for a sufficiently large damping parameter in the ener...
1912.08752v2
2020-01-17
Bounding the Classical Capacity of Multilevel Damping Quantum Channels
A recent method to certify the classical capacity of quantum communication channels is applied for general damping channels in finite dimension. The method compares the mutual information obtained by coding on the computational and a Fourier basis, which can be obtained by just two local measurement settings and classi...
2001.06486v2
2020-01-27
Robustness of polynomial stability of damped wave equations
In this paper we present new results on the preservation of polynomial stability of damped wave equations under addition of perturbing terms. We in particular introduce sufficient conditions for the stability of perturbed two-dimensional wave equations on rectangular domains, a one-dimensional weakly damped Webster's e...
2001.10033v3
2020-02-16
Blow up results for semi-linear structural damped wave model with nonlinear memory
This article is to study the nonexistence of global solutions to semi-linear structurally damped wave equation with nonlinear memory in $\R^n$ for any space dimensions $n\ge 1$ and for the initial arbitrarily small data being subject to the positivity assumption. We intend to apply the method of a modified test functio...
2002.06582v1
2020-03-04
Existence and uniqueness of solutions to the damped Navier-Stokes equations with Navier boundary conditions for three dimensional incompressible fluid
In this article, we study the solutions of the damped Navier--Stokes equation with Navier boundary condition in a bounded domain $\Omega$ in $\mathbb{R}^3$ with smooth boundary. The existence of the solutions is global with the damped term $\vartheta |u|^{\beta-1}u, \vartheta >0.$ The regularity and uniqueness of solut...
2003.01903v1
2020-04-22
Logarithmic stabilization of an acoustic system with a damping term of Brinkman type
We study the problem of stabilization for the acoustic system with a spatially distributed damping. Without imposing any hypotheses on the structural properties of the damping term, we identify logarithmic decay of solutions with growing time. Logarithmic decay rate is shown by using a frequency domain method and combi...
2004.10669v1
2020-06-09
Lifespan of solutions to a damped fourth-order wave equation with logarithmic nonlinearity
This paper is devoted to the lifespan of solutions to a damped fourth-order wave equation with logarithmic nonlinearity $$u_{tt}+\Delta^2u-\Delta u-\omega\Delta u_t+\alpha(t)u_t=|u|^{p-2}u\ln|u|.$$ Finite time blow-up criteria for solutions at both lower and high initial energy levels are established, and an upper boun...
2006.05006v1
2020-07-05
Oscillation of damped second order quasilinear wave equations with mixed arguments
Following the previous work [1], we investigate the impact of damping on the oscillation of smooth solutions to some kind of quasilinear wave equations with Robin and Dirichlet boundary condition. By using generalized Riccati transformation and technical inequality method, we give some sufficient conditions to guarante...
2007.02284v1
2020-07-08
A competition on blow-up for semilinear wave equations with scale-invariant damping and nonlinear memory term
In this paper, we investigate blow-up of solutions to semilinear wave equations with scale-invariant damping and nonlinear memory term in $\mathbb{R}^n$, which can be represented by the Riemann-Liouville fractional integral of order $1-\gamma$ with $\gamma\in(0,1)$. Our main interest is to study mixed influence from da...
2007.03954v2
2020-08-02
Quantum capacity analysis of multi-level amplitude damping channels
The set of Multi-level Amplitude Damping (MAD) quantum channels is introduced as a generalization of the standard qubit Amplitude Damping Channel to quantum systems of finite dimension $d$. In the special case of $d=3$, by exploiting degradability, data-processing inequalities, and channel isomorphism, we compute the a...
2008.00477v3
2020-08-17
Asymptotic profiles and singular limits for the viscoelastic damped wave equation with memory of type I
In this paper, we are interested in the Cauchy problem for the viscoelastic damped wave equation with memory of type I. By applying WKB analysis and Fourier analysis, we explain the memory's influence on dissipative structures and asymptotic profiles of solutions to the model with weighted $L^1$ initial data. Furthermo...
2008.07151v1
2020-09-11
Asymptotic profiles for a wave equation with parameter dependent logarithmic damping
We study a nonlocal wave equation with logarithmic damping which is rather weak in the low frequency zone as compared with frequently studied strong damping case. We consider the Cauchy problem for this model in the whole space and we study the asymptotic profile and optimal estimates of the solutions and the total ene...
2009.06395v1
2020-09-17
Sensitivity of steady states in a degenerately-damped stochastic Lorenz system
We study stability of solutions for a randomly driven and degenerately damped version of the Lorenz '63 model. Specifically, we prove that when damping is absent in one of the temperature components, the system possesses a unique invariant probability measure if and only if noise acts on the convection variable. On the...
2009.08429v1
2021-02-20
Lifespan estimates for semilinear wave equations with space dependent damping and potential
In this work, we investigate the influence of general damping and potential terms on the blow-up and lifespan estimates for energy solutions to power-type semilinear wave equations. The space-dependent damping and potential functions are assumed to be critical or short range, spherically symmetric perturbation. The blo...
2102.10257v1
2021-02-24
Attractors for locally damped Bresse systems and a unique continuation property
This paper is devoted to Bresse systems, a robust model for circular beams, given by a set of three coupled wave equations. The main objective is to establish the existence of global attractors for dynamics of semilinear problems with localized damping. In order to deal with localized damping a unique continuation prop...
2102.12025v1
2021-03-09
Global weak solution of 3D-NSE with exponential damping
In this paper we prove the global existence of incompressible Navier-Stokes equations with damping $\alpha (e^{\beta |u|^2}-1)u$, where we use Friedrich method and some new tools. The delicate problem in the construction of a global solution, is the passage to the limit in exponential nonlinear term. To solve this prob...
2103.05388v1
2021-05-03
Enhanced and unenhanced dampings of Kolmogorov flow
In the present study, Kolmogorov flow represents the stationary sinusoidal solution $(\sin y,0)$ to a two-dimensional spatially periodic Navier-Stokes system, driven by an external force. This system admits the additional non-stationary solution $(\sin y,0)+e^{-\nu t} (\sin y,0)$, which tends exponentially to the Kolmo...
2105.00730v2
2021-05-06
On Linear Damping Around Inhomogeneous Stationary States of the Vlasov-HMF Model
We study the dynamics of perturbations around an inhomogeneous stationary state of the Vlasov-HMF (Hamiltonian Mean-Field) model, satisfying a linearized stability criterion (Penrose criterion). We consider solutions of the linearized equation around the steady state, and prove the algebraic decay in time of the Fourie...
2105.02484v1
2021-05-31
Blowup of Solutions to a Damped Euler Equation with Homogeneous Three-Point Boundary Condition
It has been established that solutions to the inviscid Proudman-Johnson equation subject to a homogeneous three-point boundary condition can develop singularities in finite time. In this paper, we consider the possibility of singularity formation in solutions of the generalized, inviscid Proudman-Johnson equation with ...
2106.00068v1
2021-06-23
Damping of the Franz-Keldysh oscillations in the presence of disorder
Franz-Keldysh oscillations of the optical absorption in the presence of short-range disorder are studied theoretically. The magnitude of the effect depends on the relation between the mean-free path in a zero field and the distance between the turning points in electric field. Damping of the Franz-Keldysh oscillations ...
2106.12691v1
2021-07-01
Event-triggering mechanism to damp the linear wave equation
This paper aims at proposing a sufficient matrix inequality condition to carry out the global exponential stability of the wave equation under an event-triggering mechanism that updates a damping source term. The damping is distributed in the whole space but sampled in time. The wellposedness of the closed-loop event-t...
2107.00292v1
2022-01-28
Quantum metrology with a non-linear kicked Mach-Zehnder interferometer
We study the sensitivity of a Mach-Zehnder interferometer that contains in addition to the phase shifter a non-linear element. By including both elements in a cavity or a loop that the light transverses many times, a non-linear kicked version of the interferometer arises. We study its sensitivity as function of the pha...
2201.12255v1
2022-02-27
The time asymptotic expansion for the compressible Euler equations with time-dependent damping
In this paper, we study the compressible Euler equations with time-dependent damping $-\frac{1}{(1+t)^{\lambda}}\rho u$. We propose a time asymptotic expansion around the self-similar solution of the generalized porous media equation (GPME) and rigorously justify this expansion as $\lambda \in (\frac17,1)$. In other wo...
2202.13385v1
2022-03-30
A Toy Model for Damped Water Waves
We consider a toy model for a damped water waves system in a domain $\Omega_t \subset \mathbb{T} \times \mathbb{R}$. The toy model is based on the paradifferential water waves equation derived in the work of Alazard-Burq-Zuily. The form of damping we utilize we utilize is a modified sponge layer proposed for the three-...
2203.16645v1
2022-05-10
Global attractor for the weakly damped forced Kawahara equation on the torus
We study the long time behaviour of solutions for the weakly damped forced Kawahara equation on the torus. More precisely, we prove the existence of a global attractor in $L^2$, to which as time passes all solutions draw closer. In fact, we show that the global attractor turns out to lie in a smoother space $H^2$ and b...
2205.04642v1
2022-10-24
The time asymptotic expansion for the compressible Euler equations with damping
In 1992, Hsiao and Liu \cite{Hsiao-Liu-1} firstly showed that the solution to the compressible Euler equations with damping time-asymptotically converges to the diffusion wave $(\bar v, \bar u)$ of the porous media equation. In \cite{Geng-Huang-Jin-Wu}, we proposed a time-asymptotic expansion around the diffusion wave ...
2210.13157v1
2023-02-09
A remark on the logarithmic decay of the damped wave and Schrödinger equations on a compact Riemannian manifold
In this paper we consider a compact Riemannian manifold (M, g) of class C 1 $\cap$ W 2,$\infty$ and the damped wave or Schr\"odinger equations on M , under the action of a damping function a = a(x). We establish the following fact: if the measure of the set {x $\in$ M ; a(x) = 0} is strictly positive, then the decay in...
2302.04498v1
2023-03-02
Using vibrating wire in non-linear regime as a thermometer in superfluid $^3$He-B
Vibrating wires are common temperature probes in $^3$He experiments. By measuring mechanical resonance of a wire driven by AC current in magnetic field one can directly obtain temperature-dependent viscous damping. This is easy to do in a linear regime where wire velocity is small enough and damping force is proportion...
2303.01189v1
2023-04-06
A turbulent study for a damped Navier-Stokes equation: turbulence and problems
In this article we consider a damped version of the incompressible Navier-Stokes equations in the whole three-dimensional space with a divergence-free and time-independent external force. Within the framework of a well-prepared force and with a particular choice of the damping parameter, when the Grashof numbers are la...
2304.03134v1
2023-05-13
Global existence for a 3D Tropical Climate Model with damping and small initial data in $\dot H^{1/2}(\mathbb{R}^3)$
We consider a 3D Tropical Climate Model with damping terms in the equation of the barotropic mode $u$ and in the equation of the first baroclinic mode $v$ of the velocity. The equation for the temperature $\theta$ is free from dampings. We prove global existence in time for this system assuming the initial data $(u_0, ...
2305.07964v1
2023-06-21
The effect of singularities and damping on the spectra of photonic crystals
Understanding the dispersive properties of photonic crystals is a fundamental and well-studied problem. However, the introduction of singular permittivities and damping complicates the otherwise straightforward theory. In this paper, we study photonic crystals with a Drude-Lorentz model for the permittivity, motivated ...
2306.12254v1
2023-07-25
Asymptotic behavior and life-span estimates for the damped inhomogeneous nonlinear Schrödinger equation
We are interested in the behavior of solutions to the damped inhomogeneous nonlinear Schr\"odinger equation $ i\partial_tu+\Delta u+\mu|x|^{-b}|u|^{\alpha}u+iau=0$, $\mu \in\mathbb{C} $, $b>0$, $a \in \mathbb{C}$ such that $\Re \textit{e}(a) \geq 0$, $\alpha>0$. We establish lower and upper bound estimates of the life-...
2307.13495v1
2023-07-26
On nonlinear Landau damping and Gevrey regularity
In this article we study the problem of nonlinear Landau damping for the Vlasov-Poisson equations on the torus. As our main result we show that for perturbations initially of size $\epsilon>0$ and time intervals $(0,\epsilon^{-N})$ one obtains nonlinear stability in regularity classes larger than Gevrey $3$, uniformly ...
2307.14271v1
2023-08-18
Damping for fractional wave equations and applications to water waves
Motivated by numerically modeling surface waves for inviscid Euler equations, we analyze linear models for damped water waves and establish decay properties for the energy for sufficiently regular initial configurations. Our findings give the explicit decay rates for the energy, but do not address reflection/transmissi...
2308.09288v1
2023-08-30
Optimal decay for one-dimensional damped wave equations with potentials via a variant of Nash inequality
The optimality of decay properties of the one-dimensional damped wave equations with potentials belonging to a certain class is discussed. The typical ingredient is a variant of Nash inequality which involves an invariant measure for the corresponding Schr\"odinger semigroup. This enables us to find a sharp decay estim...
2308.15680v1
2023-09-15
Explicit solutions and linear inviscid damping in the Euler-Boussinesq equation near a stratified Couette flow in the periodic strip
This short note provides explicit solutions to the linearized Boussinesq equations around the stably stratified Couette flow posed on $\mathbb{T}\times\mathbb{R}$. We consider the long-time behavior of such solutions and prove inviscid damping of the perturbed density and velocity field for any positive Richardson numb...
2309.08419v2
2023-09-21
Beyond Qubits : An Extensive Noise Analysis for Qutrit Quantum Teleportation
The four quantum noises Bit Flip, Phase Flip, Depolarization, and Amplitude Damping as well as any potential combinations of them are examined in this papers investigation of quantum teleportation using qutrit states. Among the above mentioned noises, we observed phase flip has highest fidelity. Compared to uncorrelate...
2309.12163v1
2023-12-22
Soliton resolution for the energy critical damped wave equations in the radial case
We consider energy-critical damped wave equation \begin{equation*} \partial_{tt}u-\Delta u+\alpha \partial_t u=\left|u\right|^{\frac{4}{D-2}}u \end{equation*} with radial initial data in dimensions $D\geq 4$. The equation has a nontrivial radial stationary solution $W$, called the ground state, which is unique up to si...
2401.04115v2
2024-02-18
Sharp lifespan estimate for the compressible Euler system with critical time-dependent damping in $\R^2$
This paper concerns the long time existence to the smooth solutions of the compressible Euler system with critical time dependent damping in $\R^2$. We establish the sharp lifespan estimate from below, with respect to the small parameter of the initial perturbation. For this end, the vector fields $\widehat{Z}$ (define...
2402.11516v1
2024-02-28
Linear inviscid damping in the presence of an embedding eigenvalue
In this paper, we investigate the long-time dynamics of the linearized 2-D Euler equations around a hyperbolic tangent flow $(\tanh y,0)$. A key difference compared to previous results is that the linearized operator has an embedding eigenvalue, which has a significant impact on the dynamics of the linearized system. F...
2402.18229v1
2024-03-19
Improved decay results for micropolar flows with nonlinear damping
We examine the long-time behavior of solutions (and their derivatives) to the micropolar equations with nonlinear velocity damping. Additionally, we get a speed-up gain of $ t^{1/2} $ for the angular velocity, consistent with established findings for classic micropolar flows lacking nonlinear damping. Consequently, we ...
2403.12885v1
1994-05-02
Damped Lyman Alpha Systems vs. Cold + Hot Dark Matter
Although the Cold + Hot Dark Matter (CHDM) cosmology provides perhaps the best fit of any model to all the available data at the current epoch, CHDM produces structure at relatively low redshifts and thus could be ruled out if there were evidence for formation of massive objects at high redshifts. Damped Ly$\alpha$ sys...
9405003v1
1995-03-24
High Redshift Lyman Limit and Damped Lyman-Alpha Absorbers
We have obtained high signal:to:noise optical spectroscopy at 5\AA\ resolution of 27 quasars from the APM z$>$4 quasar survey. The spectra have been analyzed to create new samples of high redshift Lyman-limit and damped Lyman-$\alpha$ absorbers. These data have been combined with published data sets in a study of the r...
9503089v1
1997-05-15
Cosmological Constraints from High-Redshift Damped Lyman-Alpha Systems
Any viable cosmological model must produce enough structure at early epochs to explain the amount of gas associated with high-redshift damped Ly$\alpha$ systems. We study the evolution of damped Ly$\alpha$ systems at redshifts $z\ge 2$ in cold dark matter (CDM) and cold+hot dark matter (CDM+HDM) models using both N-bod...
9705113v1
2001-01-03
Galactic Chemical Abundances at z>3 I: First Results from the Echellette Spectrograph and Imager
We present the first results from an ongoing survey to discover and measure the metallicity of z>3 damped Lya systems with the Echellette Spectrograph and Imager (ESI) on the Keck II telescope. Our motivation arises from a recent study on the damped Lya systems suggesting only mild evolution in the cosmic metallicity f...
0101029v1
2002-01-17
Self-shielding Effects on the Column Density Distribution of Damped Lyman Alpha Systems
We calculate the column density distribution of damped Lyman alpha systems, modeled as spherical isothermal gaseous halos ionized by the external cosmic background. The effects of self-shielding introduce a hump in this distribution, at a column density N_{HI} \sim 1.6x10^{17} X^{-1} cm^{-2}, where X is the neutral fra...
0201275v2
2002-04-30
Two-phase equilibrium and molecular hydrogen formation in damped Lyman-alpha systems
Molecular hydrogen is quite underabundant in damped Lyman-alpha systems at high redshift, when compared to the interstellar medium near the Sun. This has been interpreted as implying that the gas in damped Lyman-alpha systems is warm. like the nearby neutral intercloud medium, rather than cool, as in the clouds which g...
0204515v1
2003-05-12
Ordinary and Viscosity-Damped MHD Turbulence
We compare the properties of ordinary strong magnetohydrodynamic (MHD) turbulence in a strongly magnetized medium with the recently discovered viscosity-damped regime. We focus on energy spectra, anisotropy, and intermittency. Our most surprising conclusion is that in ordinary strong MHD turbulence the velocity and mag...
0305212v2
2003-09-17
Observational Tests of Damping by Resonant Absorption in Coronal Loop Oscillations
One of the proposed damping mechanisms of coronal (transverse) loop oscillations in the kink-mode is resonant absorption as a result of the Alfven speed variation at the outer boundary of coronal loops. Analytical expressions for the period and damping time exist for loop models with thin non-uniform boundaries. Here w...
0309470v1
2005-03-01
Metal Abundances in a Damped Lyman-alpha System Along Two Lines of Sight at z=0.93
We study metal abundances in the z=0.9313 damped Lya system observed in the two lines-of-sight, A and B, toward the gravitationally-lensed double QSO HE0512-3329. Spatially resolved STIS spectra constrain the neutral-gas column density to be LogN(HI)=20.5 in both Aand B. UVES spectra (spectral resolution FWHM=9.8 km/s)...
0503026v1
2000-08-26
Adsorbate aggregation and relaxation of low-frequency vibrations
We present a study of resonant vibrational coupling between adsorbates and an elastic substrate at low macroscopic coverages. In the first part of the paper we consider the situation when adsorbates form aggregates with high local coverage. Based upon our previously published theory, we derive formulas describing the d...
0008389v1
2004-10-26
Mean-field treatment of the damping of the oscillations of a 1D Bose gas in an optical lattice
We present a theoretical treatment of the surprisingly large damping observed recently in one-dimensional Bose-Einstein atomic condensates in optical lattices. We show that time-dependent Hartree-Fock-Bogoliubov (HFB) calculations can describe qualitatively the main features of the damping observed over a range of latt...
0410677v4
1998-10-16
Fermion Damping in a Fermion-Scalar Plasma
In this article we study the dynamics of fermions in a fermion-scalar plasma. We begin by obtaining the effective in-medium Dirac equation in real time which is fully renormalized and causal and leads to the initial value problem. For a heavy scalar we find the novel result that the decay of the scalar into fermion pai...
9810393v2
2006-01-06
Wave energy localization by self-focusing in large molecular structures: a damped stochastic discrete nonlinear Schroedinger equation model
Wave self-focusing in molecular systems subject to thermal effects, such as thin molecular films and long biomolecules, can be modeled by stochastic versions of the Discrete Self-Trapping equation of Eilbeck, Lomdahl and Scott, and this can be approximated by continuum limits in the form of stochastic nonlinear Schroed...
0601017v1
2007-11-15
Effect of the steady flow on spatial damping of small-amplitude prominence oscillations
Aims. Taking account of steady flow in solar prominences, we study its effects on spatial damping of small-amplitude non-adiabatic magnetoacoustic waves in a homogeneous, isothermal, and unbounded prominence plasma. Methods. We model the typical feature of observed damped oscillatory motion in prominences, removing the...
0711.2353v1
2011-04-13
Evolution of inclined planets in three-dimensional radiative discs
While planets in the solar system only have a low inclination with respect to the ecliptic there is mounting evidence that in extrasolar systems the inclination can be very high, at least for close-in planets. One process to alter the inclination of a planet is through planet-disc interactions. Recent simulations consi...
1104.2408v1
2011-07-12
Mode conversion of radiatively damped magnetogravity waves in the solar chromosphere
Modelling of adiabatic gravity wave propagation in the solar atmosphere showed that mode conversion to field guided acoustic waves or Alfv\'en waves was possible in the presence of highly inclined magnetic fields. This work aims to extend the previous adiabatic study, exploring the consequences of radiative damping on ...
1107.2208v1
2013-09-23
Phonon-mediated damping of mechanical vibrations in a finite atomic chain coupled to an outer environment
We study phonon-mediated damping of mechanical vibrations in a finite quantum-mechanical atomic-chain model. Our study is motivated by the quest to understand the quality factors (Q) of nanomechanical resonators and nanoelectromechanical systems (NEMS), as well as actual experiments with suspended atomic chains and mol...
1309.5772v1
2014-04-01
Stellar dynamics in gas: The role of gas damping
In this paper, we consider how gas damping affects the dynamical evolution of gas-embedded star clusters. Using a simple three-component (i.e. one gas and two stellar components) model, we compare the rates of mass segregation due to two-body relaxation, accretion from the interstellar medium, and gas dynamical frictio...
1404.0379v1
2014-04-26
Landau damping effects on dust-acoustic solitary waves in a dusty negative-ion plasma
The nonlinear theory of dust-acoustic waves (DAWs) with Landau damping is studied in an unmagnetized dusty negative-ion plasma in the extreme conditions when the free electrons are absent. The cold massive charged dusts are described by fluid equations, whereas the two-species of ions (positive and negative) are descri...
1404.6623v3
2015-03-31
Damping of Confined Excitations Modes of 1D Condensates in an Optical Lattice
We study the damping of the collective excitations of Bose-Einstein condensates in a harmonic trap potential loaded in an optical lattice. In the presence of a confining potential the system is non-homogeneous and the collective excitations are characterized by a set of discrete confined phonon-like excitations. We der...
1503.08884v2
2015-08-06
On the spatial scales of wave heating in the solar chromosphere
Dissipation of magnetohydrodynamic (MHD) wave energy has been proposed as a viable heating mechanism in the solar chromospheric plasma. Here, we use a simplified one-dimensional model of the chromosphere to theoretically investigate the physical processes and the spatial scales that are required for the efficient dissi...
1508.01497v1
2015-11-11
A statistical study of decaying kink oscillations detected using SDO/AIA
Despite intensive studies of kink oscillations of coronal loops in the last decade, a large scale statistically significant investigation of the oscillation parameters has not been made using data from the Solar Dynamics Observatory (SDO). We carry out a statistical study of kink oscillations using Extreme Ultra-Viol...
1511.03558v1
2016-03-01
A comparative study of protocols for secure quantum communication under noisy environment: single-qubit-based protocols versus entangled-state-based protocols
The effect of noise on various protocols of secure quantum communication has been studied. Specifically, we have investigated the effect of amplitude damping, phase damping, squeezed generalized amplitude damping, Pauli type as well as various collective noise models on the protocols of quantum key distribution, quantu...
1603.00178v1
2016-11-17
A stable partitioned FSI algorithm for rigid bodies and incompressible flow. Part I: Model problem analysis
A stable partitioned algorithm is developed for fluid-structure interaction (FSI) problems involving viscous incompressible flow and rigid bodies. This {\em added-mass partitioned} (AMP) algorithm remains stable, without sub-iterations, for light and even zero mass rigid bodies when added-mass and viscous added-damping...
1611.05711v1
2017-01-30
Torsional Alfvén resonances as an efficient damping mechanism for non-radial oscillations in red giant stars
Stars are self-gravitating fluids in which pressure, buoyancy, rotation and magnetic fields provide the restoring forces for global modes of oscillation. Pressure and buoyancy energetically dominate, while rotation and magnetism are generally assumed to be weak perturbations and often ignored. However, observations of ...
1701.08771v1
2018-03-30
Damping of gravitational waves in a viscous Universe and its implication for dark matter self-interactions
It is well known that a gravitational wave (GW) experiences the damping effect when it propagates in a fluid with nonzero shear viscosity. In this paper, we propose a new method to constrain the GW damping rate and thus the fluid shear viscosity. By defining the effective distance which incorporates damping effects, we...
1803.11397v1
2018-05-29
Basic microscopic plasma physics from N-body mechanics
Computing is not understanding. This is exemplified by the multiple and discordant interpretations of Landau damping still present after seventy years. For long deemed impossible, the mechanical N-body description of this damping, not only enables its rigorous and simple calculation, but makes unequivocal and intuitive...
1805.11408v2
2018-08-22
Constructing a boosted, spinning black hole in the damped harmonic gauge
The damped harmonic gauge is important for numerical relativity computations based on the generalized harmonic formulation of Einstein's equations, and is used to reduce coordinate distortions near binary black hole mergers. However, currently there is no prescription to construct quasiequilibrium binary black hole ini...
1808.07490v3
2018-12-13
Neutrino damping in a fermion and scalar background
We consider the propagation of a neutrino in a background composed of a scalar particle and a fermion using a simple model for the coupling of the form $\lambda\bar f_R\nu_L\phi$. In the presence of these interactions there can be damping terms in the neutrino effective potential and index of refraction. We calculate t...
1812.05672v2
2019-04-25
High Spin-Wave Propagation Length Consistent with Low Damping in a Metallic Ferromagnet
We report ultra-low intrinsic magnetic damping in Co$_{\text{25}}$Fe$_{\text{75}}$ heterostructures, reaching the low $10^{-4}$ regime at room temperature. By using a broadband ferromagnetic resonance technique, we extracted the dynamic magnetic properties of several Co$_{\text{25}}$Fe$_{\text{75}}$-based heterostructu...
1904.11321v3
2019-11-02
Soft contribution to the damping rate of a hard photon in a weakly magnetized hot medium
We consider weakly magnetized hot QED plasma comprising electrons and positrons. There are three distinct dispersive (longitudinal and two transverse) modes of a photon in a thermo-magnetic medium. At lowest order in coupling constant, photon is damped in this medium via Compton scattering and pair creation process. We...
1911.00744v2
2020-09-25
Temperature dependence of the damping parameter in the ferrimagnet Gd$_3$Fe$_5$O$_{12}$
The damping parameter ${\alpha}_{\text{FM}}$ in ferrimagnets defined according to the conventional practice for ferromagnets is known to be strongly temperature dependent and diverge at the angular momentum compensation temperature, where the net angular momentum vanishes. However, recent theoretical and experimental d...
2009.12073v2
2020-09-25
A Complex Stiffness Human Impedance Model with Customizable Exoskeleton Control
The natural impedance, or dynamic relationship between force and motion, of a human operator can determine the stability of exoskeletons that use interaction-torque feedback to amplify human strength. While human impedance is typically modelled as a linear system, our experiments on a single-joint exoskeleton testbed i...
2009.12446v1
2020-11-26
On the stabilization of breather-type solutions of the damped higher order nonlinear Schrödinger equation
Spatially periodic breather solutions (SPBs) of the nonlinear Schr\"o\-dinger (NLS) equation are frequently used to model rogue waves and are typically unstable. In this paper we study the effects of dissipation and higher order nonlinearities on the stabilization of both single and multi-mode SPBs in the framework of ...
2011.13334v1
2020-12-22
Comparison of local and global gyrokinetic calculations of collisionless zonal flow damping in quasi-symmetric stellarators
The linear collisionless damping of zonal flows is calculated for quasi-symmetric stellarator equilibria in flux-tube, flux-surface, and full-volume geometry. Equilibria are studied from the quasi-helical symmetry configuration of the Helically Symmetric eXperiment (HSX), a broken symmetry configuration of HSX, and the...
2012.12213v2
2020-12-31
Damping of slow surface kink modes in solar photospheric waveguides modeled by one-dimensional inhomogeneities
Given the recent interest in magnetohydrodynamic (MHD) waves in pores and sunspot umbrae, we examine the damping of slow surface kink modes (SSKMs) by modeling solar photospheric waveguides with a cylindrical inhomogeneity comprising a uniform interior, a uniform exterior, and a continuous transition layer (TL) in betw...
2012.15426v1
2021-02-24
Finding the mechanism of wave energy flux damping in solar pores using numerical simulations
Context. Solar magnetic pores are, due to their concentrated magnetic fields, suitable guides for magnetoacoustic waves. Recent observations have shown that propagating energy flux in pores is subject to strong damping with height; however, the reason is still unclear. Aims. We investigate possible damping mechanisms n...
2102.12420v1
2022-04-08
Damped Strichartz estimates and the incompressible Euler--Maxwell system
Euler--Maxwell systems describe the dynamics of inviscid plasmas. In this work, we consider an incompressible two-dimensional version of such systems and prove the existence and uniqueness of global weak solutions, uniformly with respect to the speed of light $c\in (c_0,\infty)$, for some threshold value $c_0>0$ depend...
2204.04277v3
2022-05-11
A new look at the frequency-dependent damping of slow-mode waves in the solar corona
Being directly observed in the Doppler shift and imaging data and indirectly as quasi-periodic pulsations in solar and stellar flares, slow magnetoacoustic waves offer an important seismological tool for probing many vital parameters of the coronal plasma. A recently understood active nature of the solar corona for mag...
2205.05346v1
2022-12-13
The Effect of Internal Damping on Locomotion in Frictional Environments
The gaits of undulating animals arise from a complex interaction of their central nervous system, muscle, connective tissue, bone, and environment. As a simplifying assumption, many previous studies have often assumed that sufficient internal force is available to produce observed kinematics, thus not focusing on quant...
2212.06290v1
2023-01-19
Inverse Problems of Identifying the Unknown Transverse Shear Force in the Euler-Bernoulli Beam with Kelvin-Voigt Damping
In this paper, we study the inverse problems of determining the unknown transverse shear force $g(t)$ in a system governed by the damped Euler-Bernoulli equation $\rho(x)u_{tt}+\mu(x)u_t+ (r(x)u_{xx})_{xx}+ (\kappa(x)u_{xxt})_{xx}=0, ~(x,t)\in (0,\ell)\times(0,T],$ subject to the boundary conditions $u(0,t) =0$, $u_{x}...
2301.07931v1
2023-03-28
Escape Kinetics of an Underdamped Colloidal Particle from a Cavity through Narrow Pores
It is often desirable to know the controlling mechanism of survival probability of nano - or microscale particles in small cavities such as, e.g., confined submicron particles in fiber beds of high-efficiency filter media or ions/small molecules in confined cellular structures. Here we address this issue based on numer...
2303.16092v1
2023-06-05
Damping of coronal oscillations in self-consistent 3D radiative MHD simulations of the solar atmosphere
Oscillations are abundant in the solar corona. Coronal loop oscillations are typically studied using highly idealised models of magnetic flux tubes. In order to improve our understanding of coronal oscillations, it is necessary to consider the effect of realistic magnetic field topology and density structuring. We anal...
2306.02770v1
2023-08-22
Investigating the characteristic shape and scatter of intergalactic damping wings during reionization
Ly$\alpha$ damping wings in the spectra of bright objects at high redshift are a useful probe of the ionization state of the intergalactic medium during the reionization epoch. It has recently been noted that, despite the inhomogeneous nature of reionization, these damping wings have a characteristic shape which is a s...
2308.11709v1
2023-10-02
Characterizing the Velocity-Space Signature of Electron Landau Damping
Plasma turbulence plays a critical role in the transport of energy from large-scale magnetic fields and plasma flows to small scales, where the dissipated turbulent energy ultimately leads to heating of the plasma species. A major goal of the broader heliophysics community is to identify the physical mechanisms respons...
2310.01242v2
2024-01-23
Damped kink motions in a system of two solar coronal tubes with elliptic cross-sections
This study is motivated by observations of coordinated transverse displacements in neighboring solar active region loops, addressing specifically how the behavior of kink motions in straight two-tube equilibria is impacted by tube interactions and tube cross-sectional shapes.We work with linear, ideal, pressureless mag...
2401.12885v2
1995-02-08
The Chemical Evolution of Damped Lyman Alpha Galaxies
Measurements of element abundances in damped Lyman alpha systems are providing new means to investigate the chemical evolution of galaxies, particularly at early times. We review progress in this area, concentrating on recent efforts to extend the range of existing surveys to both higher and lower redshifts.
9502047v1
1996-01-19
The Chemical Enrichment History of Damped Lyman-alpha Galaxies
Studies of damped Lyman-alpha absorption systems in quasar spectra are yielding very interesting results regarding the chemical evolution of these galaxies. We present some preliminary results from such a program.
9601098v1
1997-01-30
Initial Chemical Enrichment in Galaxies
We present evidence that damped Lyman-alpha galaxies detected in spectra of quasars may not have started forming stars until the redshift z~3. If damped Lyman-alpha absorbers are the progenitors of disk galaxies, then the above result may indicate that star formation in galactic disks first began at z~3.
9701241v1
1997-10-24
The N/Si Abundance Ratio in Fifteen Damped Lyman-alpha Galaxies: Implications for the Origin of Nitrogen
Galactic chemical evolution model calculations indicate that there should be considerable scatter in the observed N/O ratios at a fixed metallicity (O/H) for galaxies with very low metallicities due to the delayed release of primary N from intermediate mass stars relative to that of O from short-lived massive stars. Mo...
9710266v2
2001-06-05
On Nonlinear Alfvén Waves Generated by Cosmic Ray Streaming Instability
Nonlinear damping of parallel propagating Alfv\'en waves in high-$\beta$ plasma is considered. Trapping of thermal ions and Coulomb collisions are taken into account. Saturated damping rate is calculated. Applications are made for cosmic ray propagation in the Galaxy.
0106078v1
2001-10-15
The UCSD HIRES/KeckI Damped Lya Abundance Database: II. The Implications
We present a comprehensive analysis of the damped Lya abundance database presented in the first paper of this series. This database provides a homogeneous set of abundance measurements for many elements including Si, Cr, Ni, Zn, Fe, Al, S, Co, O, and Ar from 38 damped Lya systems with z > 1.5. With little exception, th...
0110351v1
2005-09-05
Comment on "Damping of Tensor Modes in Cosmology"
We provide an analytic solution to the short wave length limit of the integro-differential equation describing the damping of the tensor modes of gravitational waves.
0509096v2
1997-02-12
Crossover from coherent to incoherent dynamics in damped quantum systems
The destruction of quantum coherence by environmental influences is investigated taking the damped harmonic oscillator and the dissipative two-state system as prototypical examples. It is shown that the location of the coherent-incoherent transition depends to a large degree on the dynamical quantity under consideratio...
9702115v1
1998-06-05
Dielectric formalism and damping of collective modes in trapped Bose-Einstein condensed gases
We present the general dielectric formalism for Bose-Einstein condensed systems in external potential at finite temperatures. On the basis of a model arising within this framework as a first approximation in an intermediate temperature region for large condensate we calculate the damping of low-energy excitations in th...
9806079v1