publicationDate
stringlengths
1
2.79k
title
stringlengths
1
36.5k
abstract
stringlengths
1
37.3k
id
stringlengths
9
47
2023-11-24
Black hole spectroscopy beyond Kerr: agnostic and theory-based tests with next-generation interferometers
Black hole spectroscopy is a clean and powerful tool to test gravity in the strong-field regime and to probe the nature of compact objects. Next-generation ground-based detectors, such as the Einstein Telescope and Cosmic Explorer, will observe thousands of binary black hole mergers with large signal-to-noise ratios, a...
2311.14803v3
2024-03-16
Elasto-visco-plastic flows in benchmark geometries: I. 4 to 1 Planar Contraction
We present predictions for the flow of elastoviscoplastic (EVP) fluids in the 4 to 1 planar contraction geometry. The Saramito-Herschel-Bulkley fluid model is solved via the finite-volume method with the OpenFOAM software. Both the constitutive model and the solution method require using transient simulations. In this ...
2403.10890v1
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
2006-02-09
Magnetization damping in polycrystalline Co ultra-thin films: Evidence for non-local effects
The magnetic properties and magnetization dynamics of polycrystalline ultra-thin Co layers were investigated using a broadband ferromagnetic resonance (FMR) technique at room temperature. A variable thickness (1 nm $\leq t \leq$ 10 nm) Co layer is sandwiched between 10 nm thick Cu layers (10 nm Cu| t Co|10 nm Cu), whil...
0602243v2
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
2008-02-07
Cascade and Damping of Alfvén-Cyclotron Fluctuations: Application to Solar Wind Turbulence Spectrum
With the diffusion approximation, we study the cascade and damping of Alfv\'{e}n-cyclotron fluctuations in solar plasmas numerically. Motivated by wave-wave couplings and nonlinear effects, we test several forms of the diffusion tensor. For a general locally anisotropic and inhomogeneous diffusion tensor in the wave ve...
0802.0910v1
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
2016-02-19
A systematic study of magnetodynamic properties at finite temperatures in doped permalloy from first principles calculations
By means of first principles calculations, we have systematically investigated how the magnetodynamic properties Gilbert damping, magnetization and exchange stiffness are affected when permalloy (Py) (Fe$_{0.19}$Ni$_{0.81}$) is doped with 4d or 5d transition metal impurities. We find that the trends in the Gilbert damp...
1602.06201v2
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
2020-04-09
Magnetic Damping in Epitaxial Fe Alloyed with Vanadium and Aluminum
To develop low-moment, low-damping metallic ferromagnets for power-efficient spintronic devices, it is crucial to understand how magnetic relaxation is impacted by the addition of nonmagnetic elements. Here, we compare magnetic relaxation in epitaxial Fe films alloyed with light nonmagnetic elements of V and Al. FeV al...
2004.04840v3
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
2021-09-08
Room-Temperature Intrinsic and Extrinsic Damping in Polycrystalline Fe Thin Films
We examine room-temperature magnetic relaxation in polycrystalline Fe films. Out-of-plane ferromagnetic resonance (FMR) measurements reveal Gilbert damping parameters of $\approx$ 0.0024 for Fe films with thicknesses of 4-25 nm, regardless of their microstructural properties. The remarkable invariance with film microst...
2109.03684v2
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 $u(0,t) =0$, $u_{x}...
2301.07931v1
2023-03-28
Escape Kinetics of an Underdamped Colloidal Particle from a Cavity through Narrow Pores
It is often desirable to know the controlling mechanism of survival probability of nano - or microscale particles in small cavities such as, e.g., confined submicron particles in fiber beds of high-efficiency filter media or ions/small molecules in confined cellular structures. Here we address this issue based on numer...
2303.16092v1
2023-08-22
Investigating the characteristic shape and scatter of intergalactic damping wings during reionization
Ly$\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
2023-10-07
OEDG: Oscillation-eliminating discontinuous Galerkin method for hyperbolic conservation laws
Controlling spurious oscillations is crucial for designing reliable numerical schemes for hyperbolic conservation laws. This paper proposes a novel, robust, and efficient oscillation-eliminating discontinuous Galerkin (OEDG) method on general meshes, motivated by the damping technique in [Lu, Liu, and Shu, SIAM J. Nume...
2310.04807v1
2023-12-07
Probing levitodynamics with multi-stochastic forces and the simple applications on the dark matter detection in optical levitation experiment
If the terrestrial environment is permeated by dark matter, the levitation experiences damping forces and fluctuations attributed to dark matter. This paper investigates levitodynamics with multiple stochastic forces, including thermal drag, photon recoil, feedback, etc., assuming that all of these forces adhere to the...
2312.04202v2
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
1999-05-27
Do correlations create an energy gap in electronic bilayers? Critical analysis of different approaches
This paper investigates the effect of correlations in electronic bilayers on the longitudinal collective mode structure. We employ the dielectric permeability constructed by means of the classical theory of moments. It is shown that the neglection of damping processes overestimates the role of correlations. We conclude...
9905405v1
1999-11-16
Damping of low-energy excitations of a Bose-condensed gas in the hydrodynamic regime
We develop a theory to describe the damping of elementary excitations of a Bose-condensed gas in the hydrodynamic regime for the thermal cloud. We discuss second sound in a spatially homogeneous gas and the lowest excitations of a trapped condensate.
9911238v2
2002-04-18
Faraday patterns in Bose-Einstein condensates. Amplitude equation for rolls in the parametrically driven, damped Gross-Pitaevskii equation
The parametrically driven, damped Gross-Pitaevskii equation, which models Bose-Einstein condensates in which the interatomic s-wave scattering length is modulated in time, is shown to support spatially modulated states in the form of rolls. A Landau equation with broken phase symmetry is derived, which governs the dyna...
0204406v1
2002-11-14
Sound damping in ferrofluids: Magnetically enhanced compressional viscosity
The damping of sound waves in magnetized ferrofluids is investigated and shown to be considerably higher than in the non-magnetized case. This fact may be interpreted as a field-enhanced, effective compressional viscosity -- in analogy to the ubiquitous field-enhanced shear viscosity that is known to be the reason for ...
0211297v1
2003-10-23
Input and output in damped quantum systems III: Formulation of damped systems driven by Fermion fields
A comprehensive input-output theory is developed for Fermionic input fields. Quantum stochastic differential equations are developed in both the Ito and Stratonovich forms. The major technical issue is the development of a formalism which takes account of anticommutation relations between the Fermionic driving field an...
0310542v1
2004-01-12
Nonexponential motional damping of impurity atoms in Bose-Einstein condensates
We demonstrate that the damping of the motion of an impurity atom injected at a supercritical velocity into a Bose-Einstein condensate can exhibit appreciable deviation from the exponential law on time scales of $10^{-5}$ s.
0401172v1
2005-02-21
Two Transitions in the Damping of a Unitary Fermi Gas
We measure the temperature dependence of the radial breathing mode in an optically trapped, strongly-interacting Fermi gas of $^6$Li, just above the center of a broad Feshbach resonance. The frequency remains close to the unitary hydrodynamic value, while the damping rate reveals transitions at two well-separated tempe...
0502507v1
2005-05-10
Fluctuation-dissipation considerations and damping models for ferromagnetic materials
The role of fluctuation-dissipation relations (theorems) for the magnetization dynamics with Landau-Lifshitz-Gilbert and Bloch-Bloembergen damping terms are discussed. We demonstrate that the use of the Callen-Welton fluctuation-dissipation theorem that was proven for Hamiltonian systems can give an inconsistent result...
0505259v1
1994-07-04
Cat States and Single Runs for the Damped Harmonic Oscillator
We discuss the fate of initial states of the cat type for the damped harmonic oscillator, mostly employing a linear version of the stochastic Schr\"odinger equation. We also comment on how such cat states might be prepared and on the relation of single realizations of the noise to single runs of experiments.
9407001v1
2000-10-27
Damping and the Hartree Ensemble Approximation
We study a Hartree ensemble approximation for real-time dynamics in the toy model of 1+1 dimensional scalar field theory. Damping behavior seen in numerical simulations is compared with analytical predictions based on perturbation theory in the original (non-Hartree-approximated) model.
0010054v1
1995-03-21
APPLICATIONS OF HIGH-TEMPERATURE FIELD THEORY TO HEAVY-ION COLLISIONS
A recent development in finite temperature field theory, the so-called Braaten-Pisarski method, and its application to properties of a quark-gluon plasma, possibly formed in relativistic heavy ion collisions, are reviewed. In particular parton damping rates, the energy loss of energetic partons, thermalization times, v...
9503400v1
1996-03-19
Damping Rate and Lyapunov Exponent of a Higgs Field at High Temperature
The damping rate of a Higgs field at zero momentum is calculated using the Braaten-Pisarski method and compared to the Lyapunov exponent of the classical SU(2) Yang-Mills Higgs system.
9603339v1
1997-04-30
Comments on the Erhan-Schlein model of damping the pomeron flux at small x-pomeron
We explore the theoretical and experimental consequences of a model proposed by Samim Erhan and Peter Schlein for unitarizing the diffractive amplitude by damping the pomeron flux at small x-pomeron and conclude that the model is unphysical and contradicts well established experimental data.
9704454v1
1998-03-26
The Nonlinear Spatial Damping Rate in QGP
The derivative expansion method has been used to solve the semiclassical kinetic equations of quark-gluon plasma (QGP). The nonlinear spatial damping rate, the imaginary part of the wave vector, for the longitudinal secondary color waves in the long wavelength limit has been calculated numerically.
9803455v1
2006-07-27
Long-Time Asymptotic Behavior of Dissipative Boussinesq System
In this paper, we study various dissipative mechanics associated with the Boussinesq systems which model two-dimensional small amplitude long wavelength water waves. We will show that the decay rate for the damped one-directional model equations, such as the KdV and BBM equations, holds for some of the damped Boussines...
0607708v1
2006-12-27
Stochastic inertial manifolds for damped wave equations
In this paper, stochastic inertial manifold for damped wave equations subjected to additive white noise is constructed by the Lyapunov-Perron method. It is proved that when the intensity of noise tends to zero the stochastic inertial manifold converges to its deterministic counterpart almost surely.
0612774v1
2007-01-19
On the Domain of Analyticity and Small Scales for the Solutions of the Damped-driven 2D Navier-Stokes Equations
We obtain a logarithmically sharp estimate for the space-analyticity radius of the solutions of the damped-driven 2D Navier-Stokes equations with periodic boundary conditions and relate this to the small scales in this system. This system is inspired by the Stommel--Charney barotropic ocean circulation model.
0701530v1
2002-09-04
Wigner function for damped systems
Both classical and quantum damped systems give rise to complex spectra and corresponding resonant states. We investigate how resonant states, which do not belong to the Hilbert space, fit the phase space formulation of quantum mechanics. It turns out that one may construct out of a pair of resonant states an analog of ...
0209008v1
2004-12-14
Two-Ion Dusty Plasma Waves and Landau Damping
The paper analyses the properties of dusty plasmas in the extreme conditions when the free electrons are absent. The nonlinear Korteveg de Vries equation with a nonlocal (integral) term in a small parameter approximation is derived. The conditions are determined when the integral term is essential hence the Landau damp...
0412033v1
2002-10-16
Dependence of Nuclear Level Density on Vibrational State Damping
The response function approach is proposed to include vibrational state in calculation of level density. The calculations show rather strong dependence of level density on the relaxation times of collective state damping.
0210048v1
1999-02-09
One-Dimensional Motion of Sommerfeld Sphere in Potential Hole in Classical Electrodynamics: Inside the Hole
Equation of motion of Sommerfeld sphere in the one-dimensional potential hole, produced by two equal charges on some distance from each other, is numerically investigated. Two types of solutions are found: (i) damping oscillations, (ii) oscillations without damping (radiationless motion). Solutions with growing amplitu...
9902018v3
2000-03-23
The Hawking-Unruh Temperature and Damping in a Linear Focusing Channel
The Hawking-Unruh effective temperature, hbar a* / 2 pi c k, due to quantum fluctuations in the radiation of an accelerated charged-particle beam can be used to show that transverse oscillations of the beam in a practical linear focusing channel damp to the quantum-mechanical limit. A comparison is made between this be...
0003061v1
2003-06-17
Ruchhardt Oscillator Decay- Thermodynamic basis for Hysteretic Damping
Using thermodynamic arguments based on the ideal gas law, it is shown that hysteretic (also called structural) damping is the natural form of energy dissipation for this classic oscillator that is used to measure the ratio of heat capacities for a gas.
0306136v1
2005-08-25
Rutherford scattering with radiation damping
We study the effect of radiation damping on the classical scattering of charged particles. Using a perturbation method based on the Runge-Lenz vector, we calculate radiative corrections to the Rutherford cross section, and the corresponding energy and angular momentum losses.
0508186v2
1997-03-27
Macroscopic quantum damping in SQUID rings
The measurement process is introduced in the dynamics of Josephson devices exhibiting quantum behaviour in a macroscopic degree of freedom. The measurement is shown to give rise to a dynamical damping mechanism whose experimental observability could be relevant to understand decoherence in macroscopic quantum systems.
9703052v1
2005-07-19
Radiation reaction and quantum damped harmonic oscillator
By taking a Klein-Gordon field as the environment of an harmonic oscillator and using a new method for dealing with quantum dissipative systems (minimal coupling method), the quantum dynamics and radiation reaction for a quantum damped harmonic oscillator investigated. Applying perturbation method, some transition prob...
0507179v1
2005-08-18
Density operator and entropy of the damped quantum harmonic oscillator
The expression for the density operator of the damped harmonic oscillator is derived from the master equation in the framework of the Lindblad theory for open quantum systems. Then the von Neumann entropy and effective temperature of the system are obtained. The entropy for a state characterized by a Wigner distributio...
0508141v1
2006-03-03
On the damping of the angular momentum of three harmonic oscillators
In the frame of the Lindblad theory of open quantum systems, the system of three uncoupled harmonic oscillators with opening operators linear in the coordinates and momenta of the considered system is analyzed. The damping of the angular momentum and of its projection is obtained.
0603029v1
2006-10-10
Simultaneous amplification and non-symmetric amplitude damping of two-mode Gaussian state
The evolution of two-mode Gaussian state under symmetric amplification, non-symmetric damping and thermal noise is studied. The time dependent solution of the state characteristic function is obtained. The separability criterions are given for the final state of weak amplification as well as strong amplification.
0610070v1
2007-10-13
The separability of tripartite Gaussian state with amplification and amplitude damping
Tripartite three mode Gaussian state undergoes parametric amplification and amplitude damping as well as thermal noise is studied. In the case of a state totally symmetrically interacting with the environment, the time dependent correlation matrix of the state in evolution is given. The conditions for fully separabilit...
0710.2570v1
2007-12-16
Nonadditive quantum error correcting codes adapted to the ampltitude damping channel
A family of high rate quantum error correcting codes adapted to the amplitude damping channel is presented. These codes are nonadditive and exploit self-complementarity structure to correct all first-order errors. Their rates can be higher than 1/2. The recovery operations of these codes can be generated by a simple al...
0712.2586v1
2007-12-22
Chaos in an intermittently driven damped oscillator
We observe chaotic dynamics in a damped linear oscillator, which is driven only at certain regions of phase space. Both deterministic and random drives are studied. The dynamics is characterized using standard techniques of nonlinear dynamics. Interchanging roles of determinism and stochasticity is also considered.
0712.3827v2
2008-03-01
Well-posedness of the IBVP for 2-D Euler Equations with Damping
In this paper we focus on the initial-boundary value problem of the 2-D isentropic Euler equations with damping. We prove the global-in-time existence of classical solution to the initial-boundary value problem by the method of energy estimates.
0803.0039v1
2008-03-27
Shear viscosity of degenerate electron matter
We calculate the partial electron shear viscosity $\eta_{ee}$ limited by electron-electron collisions in a strongly degenerate electron gas taking into account the Landau damping of transverse plasmons. The Landau damping strongly suppresses $\eta_{ee}$ in the domain of ultrarelativistic degenerate electrons and modifi...
0803.3893v1
2008-04-09
Stationary Oscillations in a Damped Wave Equation from Isospectral Bessel Functions
Using the isospectral partners of the Bessel functions derived by Reyes et al., we find, on one hand, that these functions show non-typical supersymmetric (SUSY) behavior and, on the other, that the isospectral partner of the classical wave equation is equivalent to that of a damped system whose oscillations do not van...
0804.1510v1
2008-06-03
Simulation study of fast ion instability in the ILC damping ring and PETRA III
The fast ion instability is simulated in different gas pressures and fill patterns for the damping ring of the International Linear Collider (ILC) and PETRA III respectively. Beam size variation due to beta function and dispersion function change is taken into account. Feedback is also applied in the simulation.
0806.0529v1
2008-08-01
Damped wave equations with dynamic boundary conditions
We discuss several classes of linear second order initial-boundary value problems, where damping terms appear in the main wave equation as well as in the dynamic boundary condition. We investigate their well-posedness and describe some qualitative properties of their solutions, including boundedness, stability, or almo...
0808.0213v1
2008-12-17
The damping of gravitational waves in dust
We examine a simple model of interaction of gravitational waves with matter (primarily represented by dust). The aim is to investigate a possible damping effect on the intensity of gravitational wave when passing through media. This might be important for gravitational wave astronomy when the sources are obscured by du...
0812.3336v1