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1997-08-11
|
A theoretical study on the damping of collective excitations in a Bose-Einstein condensate
|
We study the damping of low-lying collective excitations of condensates in a
weakly interacting Bose gas model within the framework of imaginary time path
integral. A general expression of the damping rate has been obtained in the low
momentum limit for both the very low temperature regime and the higher
temperature regime. For the latter, the result is new and applicable to recent
experiments. Theoretical predictions for the damping rate are compared with the
experimental values.
|
9708080v3
|
1997-09-24
|
Damping in dilute Bose gases: a mean-field approach
|
Damping in a dilute Bose gas is investigated using a mean-field approximation
which describes the coupled oscillations of condensate and non-condensate atoms
in the collisionless regime. Explicit results for both Landau and Beliaev
damping rates are given for non-uniform gases. In the case of uniform systems
we obtain results for the damping of phonons both at zero and finite
temperature. The isothermal compressibility of a uniform gas is also discussed.
|
9709259v1
|
2000-09-01
|
Damped Bogoliubov excitations of a condensate interacting with a static thermal cloud
|
We calculate the damping of condensate collective excitations at finite
temperatures arising from the lack of equilibrium between the condensate and
thermal atoms. We neglect the non-condensate dynamics by fixing the thermal
cloud in static equilibrium. We derive a set of generalized Bogoliubov
equations for finite temperatures that contain an explicit damping term due to
collisional exchange of atoms between the two components. We have numerically
solved these Bogoliubov equations to obtain the temperature dependence of the
damping of the condensate modes in a harmonic trap. We compare these results
with our recent work based on the Thomas-Fermi approximation.
|
0009021v2
|
2000-11-20
|
Cavity assisted quasiparticle damping in a Bose-Einstein condensate
|
We consider an atomic Bose-Einstein condensate held within an optical cavity
and interacting with laser fields. We show how the interaction of the cavity
mode with the condensate can cause energy due to excitations to be coupled to a
lossy cavity mode, which then decays, thus damping the condensate, how to
choose parameters for damping specific excitations, and how to target a range
of different excitations to potentially produce extremely cold condensates.
|
0011341v2
|
2002-12-16
|
The nonlinear damping of Bose-Einstein condensate oscillations at ultra-low temperatures
|
We analyze the damping of the transverse breathing mode in an elongated trap
at ultralow temperatures. The damping occurs due to the parametric resonance
entailing the energy transfer to the longitudinal degrees of freedom. It is
found that the nonlinear coupling between the transverse and discrete
longitudinal modes can result in an anomalous behavior of the damping as a
function of time with the partially reversed pumping of the breathing mode. The
picture revealed explains the results observed in [16].
|
0212377v2
|
2004-08-27
|
Tunable magnetization damping in transition metal ternary alloys
|
We show that magnetization damping in Permalloy, Ni80Fe20 (``Py''), can be
enhanced sufficiently to reduce post-switching magnetization precession to an
acceptable level by alloying with the transition metal osmium (Os). The damping
increases monotonically upon raising the Os-concentration in Py, at least up to
9% of Os. Other effects of alloying with Os are suppression of magnetization
and enhancement of in-plane anisotropy. Magnetization damping also increases
significantly upon alloying with the five other transition metals included in
this study (4d-elements: Nb, Ru, Rh; 5d-elements: Ta, Pt) but never as strongly
as with Os.
|
0408608v1
|
2005-03-06
|
Nonlinear damping in nanomechanical beam oscillator
|
We investigate the impact of nonlinear damping on the dynamics of a
nanomechanical doubly clamped beam. The beam is driven into nonlinear regime
and the response is measured by a displacement detector. For data analysis we
introduce a nonlinear damping term to Duffing equation. The experiment shows
conclusively that accounting for nonlinear damping effects is needed for
correct modeling of the nanomechanical resonators under study.
|
0503130v2
|
2006-05-23
|
The origin of increase of damping in transition metals with rare earth impurities
|
The damping due to rare earth impurities in transition metals is discussed in
the low concentration limit. It is shown that the increase in damping is mainly
due to the coupling of the orbital moments of the rare earth impurities and the
conduction $p$-electrons. It is shown that an itinerant picture for the host
transition ions is needed to reproduce the observed dependence of the damping
on the total angular moment of the rare earths.
|
0605583v1
|
2001-05-14
|
Simplified models of electromagnetic and gravitational radiation damping
|
In previous work the authors analysed the global properties of an approximate
model of radiation damping for charged particles. This work is put into context
and related to the original motivation of understanding approximations used in
the study of gravitational radiation damping. It is examined to what extent the
results obtained previously depend on the particular model chosen. Comparisons
are made with other models for gravitational and electromagnetic fields. The
relation of the kinetic model for which theorems were proved to certain
many-particle models with radiation damping is exhibited.
|
0105045v1
|
1994-06-07
|
Damping Rate of a Yukawa Fermion at Finite Temperature
|
The damping of a massless fermion coupled to a massless scalar particle at
finite temperature is considered using the Braaten-Pisarski resummation
technique. First the hard thermal loop diagrams of this theory are extracted
and effective Green's functions are constructed. Using these effective Green's
functions the damping rate of a soft Yukawa fermion is calculated. This rate
provides the most simple example for the damping of a soft particle. To leading
order it is proportional to $g^2T$, whereas the one of a hard fermion is of
higher order.
|
9406242v1
|
2006-05-02
|
Moduli decay in the hot early Universe
|
We consider moduli fields interacting with thermalized relativistic matter.
We determine the temperature dependence of their damping rate and find it is
dominated by thermal effects in the high temperature regime, i.e. for
temperatures larger than their mass. For a simple scalar model the damping rate
is expressed through the known matter bulk viscosity. The high temperature
damping rate is always smaller than the Hubble rate, so that thermal effects
are not sufficient for solving the cosmological moduli problem.
|
0605030v2
|
2006-11-27
|
Inviscid limit for damped and driven incompressible Navier-Stokes equations in ${{\mathbb R}^2}$
|
We consider the zero viscosity limit of long time averages of solutions of
damped and driven Navier-Stokes equations in ${\mathbb R}^2$. We prove that the
rate of dissipation of enstrophy vanishes. Stationary statistical solutions of
the damped and driven Navier-Stokes equations converge to renormalized
stationary statistical solutions of the damped and driven Euler equations.
These solutions obey the enstrophy balance.
|
0611782v1
|
2003-09-09
|
Traveling solitons in the damped driven nonlinear Schrödinger equation
|
The well known effect of the linear damping on the moving nonlinear
Schr\"odinger soliton (even when there is a supply of energy via the spatially
homogeneous driving) is to quench its momentum to zero. Surprisingly, the zero
momentum does not necessarily mean zero velocity. We show that two or more
parametrically driven damped solitons can form a complex traveling with zero
momentum at a nonzero constant speed.
All traveling complexes we have found so far, turned out to be unstable.
Thus, the parametric driving is capable of sustaining the uniform motion of
damped solitons, but some additional agent is required to stabilize it.
|
0309031v1
|
2001-11-25
|
The Landau Damping Effect and Complex-valued Nature of Physical Quantities
|
Within the framework of the hypothesis offered by authors about
complex-valued nature of physical quantities, the effect of the Landau damping
has been explored with assumption that not only frequency can be a small
imaginary component but also a wave vector. The numerical solution of the
obtained dispersion equation testifies that uncollisional damping is
accompanied in a certain region of space by antidumping of waves, and in
particular situations antidumping may prevail over damping. It is possible that
this effect may explain the experimental difficulties connected with inhibition
of instabilities of plasma in the problem of controllable thermonuclear fusion.
|
0111176v1
|
2005-10-14
|
Nontrapping arrest of Langmuir wave damping near the threshold amplitude
|
Evolution of a Langmuir wave is studied numerically for finite amplitudes
slightly above the threshold which separates damping from nondamping cases.
Arrest of linear damping is found to be a second-order effect due to ballistic
evolution of perturbations, resonant power transfer between field and
particles, and organization of phase space into a positive slope for the
average distribution function $f_{av}$ around the resonant wave phase speed
$v_\phi$. Near the threshold trapping in the wave potential does not arrest
damping or saturate the subsequent growth phase.
|
0510131v3
|
2000-06-22
|
Decoherence and Entanglement in Two-mode Squeezed Vacuum States
|
I investigate the decoherence of two-mode squeezed vacuum states by analyzing
the relative entropy of entanglement. I consider two sources of decoherence:
(i) the phase damping and (ii) the amplitude damping due to the coupling to the
thermal environment. In particular, I give the exact value of the relative
entropy of entanglement for the phase damping model. For the amplitude damping
model, I give an upper bound for the relative entropy of entanglement, which
turns out to be a good approximation for the entanglement measure in usual
experimental situations.
|
0006100v1
|
2006-08-02
|
Damped Population Oscillation in a Spontaneously Decaying Two-Level Atom Coupled to a Monochromatic Field
|
We investigate the time evolution of atomic population in a two-level atom
driven by a monochromatic radiation field, taking spontaneous emission into
account. The Rabi oscillation exhibits amplitude damping in time caused by
spontaneous emission. We show that the semiclassical master equation leads in
general to an overestimation of the damping rate and that a correct
quantitative description of the damped Rabi oscillation can thus be obtained
only with a full quantum mechanical theory.
|
0608020v1
|
2007-08-28
|
Linear frictional forces cause orbits to neither circularize nor precess
|
For the undamped Kepler potential the lack of precession has historically
been understood in terms of the Runge-Lenz symmetry. For the damped Kepler
problem this result may be understood in terms of the generalization of Poisson
structure to damped systems suggested recently by Tarasov[1]. In this
generalized algebraic structure the orbit-averaged Runge-Lenz vector remains a
constant in the linearly damped Kepler problem to leading order in the damping
coe
|
0708.3827v3
|
2008-12-11
|
Frequency-dependent Drude damping in Casimir force calculations
|
The Casimir force is calculated between Au thin films that are described by a
Drude model with a frequency dependent damping function. The model parameters
are obtained from available experimental data for Au thin films. Two cases are
considered; annealed and nonannealed films that have a different damping
function. Compared with the calculations using a Drude model with a constant
damping parameter, we observe changes in the Casimir force of a few percent.
This behavior is only observed in films of no more than 300 $\AA$ thick.
|
0812.2209v1
|
2008-12-18
|
Dipole Oscillations of a Fermi Gas in a Disordered Trap: Damping and Localization
|
We theoretically study the dipole oscillations of an ideal Fermi gas in a
disordered trap. We show that even weak disorder induces strong damping of the
oscillations and we identify a metal-insulator crossover. For very weak
disorder, we show that damping results from a dephasing effect related to weak
random perturbations of the energy spectrum. For increasing disorder, we show
that the Fermi gas crosses over to an insulating regime characterized by
strong-damping due to the proliferation of localized states.
|
0812.3501v2
|
2009-03-11
|
Confronting the damping of the baryon acoustic oscillations with observation
|
We investigate the damping of the baryon acoustic oscillations in the matter
power spectrum due to the quasinonlinear clustering and redshift-space
distortions by confronting the models with the observations of the Sloan
Digital Sky Survey luminous red galaxy sample. The chi-squared test suggests
that the observed power spectrum is better matched by models with the damping
of the baryon acoustic oscillations rather than the ones without the damping.
|
0903.1883v1
|
2009-04-10
|
Spectral deviations for the damped wave equation
|
We prove a Weyl-type fractal upper bound for the spectrum of the damped wave
equation, on a negatively curved compact manifold. It is known that most of the
eigenvalues have an imaginary part close to the average of the damping
function. We count the number of eigenvalues in a given horizontal strip
deviating from this typical behaviour; the exponent that appears naturally is
the `entropy' that gives the deviation rate from the Birkhoff ergodic theorem
for the geodesic flow. A Weyl-type lower bound is still far from reach; but in
the particular case of arithmetic surfaces, and for a strong enough damping, we
can use the trace formula to prove a result going in this direction.
|
0904.1736v1
|
2009-10-26
|
Pressure Fronts in 1D Damped Nonlinear Lattices
|
The propagation of pressure fronts (impact solutions) in 1D chains of atoms
coupled by anharmonic potentials between nearest neighbor and submitted to
damping forces preserving uniform motion, is investigated. Travelling fronts
between two regions at different uniform pressures are found numerically and
well approximate analytically. It is proven that there are three analytical
relations between the impact velocity, the compression, the front velocity and
the energy dissipation which only depend on the coupling potential and are
\textit{independent} of the damping. Such travelling front solutions cannot
exist without damping.
|
0910.4890v1
|
2009-11-05
|
Bloch oscillations in lattice potentials with controlled aperiodicity
|
We numerically investigate the damping of Bloch oscillations in a
one-dimensional lattice potential whose translational symmetry is broken in a
systematic manner, either by making the potential bichromatic or by introducing
scatterers at distinct lattice sites. We find that the damping strongly depends
on the ratio of lattice constants in the bichromatic potential, and that even a
small concentration of scatterers can lead to strong damping. Moreover,
mean-field interactions are able to counteract aperiodicity-induced damping of
Bloch oscillations.
|
0911.1108v3
|
2010-01-12
|
Decoherence and damping in ideal gases
|
The particle and current densities are shown to display damping and undergo
decoherence in ideal quantum gases. The damping is read off from the equations
of motion reminiscent of the Navier-Stokes equations and shows some formal
similarity with Landau damping. The decoherence leads to consistent density and
current histories with characteristic length and time scales given by the ideal
gas.
|
1001.1803v2
|
2010-05-14
|
The effect of spin magnetization in the damping of electron plasma oscillations
|
The effect of spin of particles in the propagation of plasma waves is studied
using a semi-classical kinetic theory for a magnetized plasma. We focus in the
simple damping effects for the electrostatic wave modes besides Landau damping.
Without taking into account more quantum effects than spin contribution to
Vlasov's equation, we show that spin produces a new damping or instability
which is proportional to the zeroth order magnetization of the system. This
correction depends on the electromagnetic part of the wave which is coupled
with the spin vector.
|
1005.2573v1
|
2010-06-01
|
Recent Progress on a Manifold Damped and Detuned Structure for CLIC
|
A damped detuned structure for the main X-band linacs of CLIC is being
investigated as an alternative design to the present baseline heavily damped
structure. In our earlier designs we studied detuned structures, operating at
11.994 GHz, with a range of dipole bandwidths in order to ensure the structure
satisfies beam dynamics and rf breakdown constraints. Here we report on the
development of a damped and detuned structure which satisfies both constraints.
Preparations for high power testing of the structure are also discussed
|
1006.0087v1
|
2010-07-21
|
Finite temperature damping of collective modes of a BCS-BEC crossover superfluid
|
A new mechanism is proposed to explain the puzzling damping of collective
excitations, which was recently observed in the experiments of strongly
interacting Fermi gases below the superfluid critical temperature on the
fermionic (BCS) side of Feshbach resonance. Sound velocity, superfluid density
and damping rate are calculated with effective field theory. We find that a
dominant damping process is due to the interaction between superfluid phonons
and thermally excited fermionic quasiparticles, in contrast to the previously
proposed pair-breaking mechanism. Results from our effective model are compared
quantitatively with recent experimental findings, showing a good agreement.
|
1007.3694v2
|
2010-08-04
|
Confinement induced by fermion damping in three-dimensional QED
|
The three-dimensional non-compact QED is known to exhibit weak confinement
when fermions acquire a finite mass via the mechanism of dynamical chiral
symmetry breaking. In this paper, we study the effect of fermion damping caused
by elastic scattering on the classical potential between fermions. By
calculating the vacuum polarization function that incorporates the fermion
damping effect, we show that fermion damping can induce a weak confinement even
when the fermions are massless and the chiral symmetry is not broken.
|
1008.0736v2
|
2011-06-22
|
Highly Damped Quasinormal Modes and the Small Scale Structure of Quantum Corrected Black Hole Exteriors
|
Quasinormal modes provide valuable information about the structure of
spacetime outside a black hole. There is also a conjectured relationship
between the highly damped quasinormal modes and the semi-classical spectrum of
the horizon area/entropy. In this paper, we show that for spacetimes
characterized by more than one scale, the "infinitely damped" modes in
principle probe the structure of spacetime outside the horizon at the shortest
length scales. We demonstrate this with the calculation of the highly damped
quasinormal modes of the non-singular, single horizon, quantum corrected black
hole derived in [14].
|
1106.4357v1
|
2012-02-20
|
Simple Non-Markovian Microscopic Models for the Depolarizing Channel of a Single Qubit
|
The archetypal one-qubit noisy channels ---depolarizing, phase-damping and
amplitude-damping channels--- describe both Markovian and non-Markovian
evolution. Simple microscopic models for the depolarizing channel, both
classical and quantum, are considered. Microscopic models which describe phase
damping and amplitude damping channels are briefly reviewed.
|
1202.4210v4
|
2012-05-11
|
On radiative damping in plasma-based accelerators
|
Radiative damping in plasma-based electron accelerators is analyzed. The
electron dynamics under combined influence of the constant accelerating force
and the classical radiation reaction force is studied. It is shown that
electron acceleration cannot be limited by radiation reaction. If initially the
accelerating force was stronger than the radiation reaction force then the
electron acceleration is unlimited. Otherwise the electron is decelerated by
radiative damping up to a certain instant of time and then accelerated without
limits. Regardless of the initial conditions the infinite-time asymptotic
behavior of an electron is governed by self-similar solution providing
unlimited acceleration. The relative energy spread induced by the radiative
damping decreases with time in the infinite-time limit.
|
1205.2436v1
|
2012-06-14
|
Damping of optomechanical disks resonators vibrating in air
|
We report on miniature GaAs disk optomechanical resonators vibrating in air
in the radiofrequency range. The flexural modes of the disks are studied by
scanning electron microscopy and optical interferometry, and correctly modeled
with the elasticity theory for annular plates. The mechanical damping is
systematically measured, and confronted with original analytical models for air
damping. Formulas are derived that correctly reproduce both the mechanical
modes and the damping behavior, and can serve as design tools for
optomechanical applications in fluidic environment.
|
1206.3032v1
|
2012-07-09
|
A Generalized Interpolation Inequality and its Application to the Stabilization of Damped Equations
|
In this paper, we establish a generalized H{\"o}lder's or interpolation
inequality for weighted spaces in which the weights are non-necessarily
homogeneous. We apply it to the stabilization of some damped wave-like
evolution equations. This allows obtaining explicit decay rates for smooth
solutions for more general classes of damping operators. In particular, for
$1-d$ models, we can give an explicit decay estimate for pointwise damping
mechanisms supported on any strategic point.
|
1207.2030v2
|
2012-07-10
|
Conformation dependent damping and generalization of fluctuation-dissipation relation
|
Damping on an object generally depends on its conformation (shape size etc.).
We consider the Langevin dynamics of a model system with a conformation
dependent damping and generalize the fluctuation dissipation relation to fit in
such a situation. We derive equilibrium distribution function for such a case
which converges to the standard Boltzmann form at the limit of uniform damping.
The results can have implications, in general, for barrier overcoming processes
where standard Boltzmann statistics is slow.
|
1207.2218v2
|
2012-10-30
|
On algebraic damping close to inhomogeneous Vlasov equilibria in multi-dimensional spaces
|
We investigate the asymptotic damping of a perturbation around inhomogeneous
stable stationary states of the Vlasov equation in spatially multi-dimensional
systems. We show that branch singularities of the Fourier-Laplace transform of
the perturbation yield algebraic dampings. In two spatial dimensions, we
classify the singularities and compute the associated damping rate and
frequency. This 2D setting also applies to spherically symmetric
self-gravitating systems. We validate the theory using a toy model and an
advection equation associated with the isochrone model, a model of spherical
self-gravitating systems.
|
1210.8040v1
|
2013-04-07
|
Phenomenological model of anomalous magnon softening and damping in half-metallic manganites
|
To describe anomalous zone-boundary softening and damping of magnons in
manganites we present a phenomenological two-fluid model containing
ferromagnetic Fermi-liquid and non-Fermi-liquid components. The Fermi-liquid
component accounts for softening of zone-boundary magnons and for the Landau
damping of magnons in the Stoner continuum arising at low frequencies due to
zero-point effects. Coupling of the Fermi-liquid and non-Fermi-liquid fluids
yields conventional long wavelength magnons damped due to their coupling with
longitudinal spin fluctuations.
|
1304.1983v1
|
2013-04-25
|
Determination of Transverse Density Structuring from Propagating MHD Waves in the Solar Atmosphere
|
We present a Bayesian seismology inversion technique for propagating
magnetohydrodynamic (MHD) transverse waves observed in coronal waveguides. The
technique uses theoretical predictions for the spatial damping of propagating
kink waves in transversely inhomogeneous coronal waveguides. It combines wave
amplitude damping length scales along the waveguide with theoretical results
for resonantly damped propagating kink waves to infer the plasma density
variation across the oscillating structures. Provided the spatial dependence of
the velocity amplitude along the propagation direction is measured and the
existence of two different damping regimes is identified, the technique would
enable us to fully constrain the transverse density structuring, providing
estimates for the density contrast and its transverse inhomogeneity length
scale.
|
1304.6869v1
|
2013-07-08
|
Optimal decay rate of the bipolar Euler-Poisson system with damping in $\mathbb{R}^3$
|
By rewriting a bipolar Euler-Poisson equations with damping into an Euler
equation with damping coupled with an Euler-Poisson equation with damping, and
using a new spectral analysis, we obtain the optimal decay results of the
solutions in $L^2$-norm, which improve theose in \cite{Li3, Wu3}. More
precisely, the velocities $u_1,u_2$ decay at the $L^2-$rate $(1+t)^{-{5}{4}}$,
which is faster than the normal $L^2-$rate $(1+t)^{-{3}{4}}$ for the Heat
equation and the Navier-Stokes equations. In addition, the disparity of two
densities $\rho_1-\rho_2$ and the disparity of two velocities $u_1-u_2$ decay
at the $L^2$-rate $(1+t)^{-2}$.
|
1307.2081v1
|
2013-07-27
|
Symmetry considerations on radiation damping
|
It is well known that a direct Lagrangian description of radiation damping is
still missing. In this paper we will use a specific approach of this problem
which is the standard way to treat the radiation damping problem. The
objectives here are to construct: a N=2 supersymmetric extension for the model
describing the radiation damping on the noncommutative plane with electric and
magnetic interactions; a dualization analysis of the original action; the
supercharge algebra and the total Hamiltonian for the system.
|
1307.7319v1
|
2014-02-10
|
Damping of a nanocantilever by paramagnetic spins
|
We compute damping of mechanical oscillations of a cantilever that contains
flipping paramagnetic spins. This kind of damping is mandated by the dynamics
of the total angular momentum, spin + mechanical. Rigorous expression for the
damping rate is derived in terms of measurable parameters. The effect of spins
on the quality factor of the cantilever can be significant in cantilevers of
small length that have large concentration of paramagnetic spins of atomic
and/or nuclear origin.
|
1402.2326v1
|
2014-02-20
|
Long-time behavior of solutions of a BBM equation with generalized damping
|
We study the long-time behavior of the solution of a damped BBM equation $u_t
+ u_x - u_{xxt} + uu_x + \mathscr{L}_{\gamma}(u) = 0$. The proposed dampings
$\mathscr{L}_{\gamma}$ generalize standards ones, as parabolic
($\mathscr{L}_{\gamma}(u)=-\Delta u$) or weak damping
($\mathscr{L}_{\gamma}(u)=\gamma u$) and allows us to consider a greater range.
After establish the local well-posedness in the energy space, we investigate
some numerical properties.
|
1402.5009v1
|
2014-02-24
|
N=2 supersymmetric radiation damping problem on a noncommutative plane
|
It is well known that a direct Lagrangian description of radiation damping is
still missing. In this paper a specific approach of this problem was used,
which is the standard way to treat the radiation damping problem. A $N=2$
supersymmetric extension for the model describing the radiation damping on the
noncommutative plane with electric and magnetic interactions was obtained. The
entire supercharge algebra and the total Hamiltonian for the system were
analyzed. Finally, noncommutativity features were introduced and its
consequences were explored..
|
1402.6996v1
|
2014-11-03
|
Renormalized solutions to the continuity equation with an integrable damping term
|
We consider the continuity equation with a nonsmooth vector field and a
damping term. In their fundamental paper, DiPerna and Lions proved that, when
the damping term is bounded in space and time, the equation is well posed in
the class of distributional solutions and the solution is transported by
suitable characteristics of the vector field. In this paper, we prove existence
and uniqueness of renormalized solutions in the case of an integrable damping
term, employing a new logarithmic estimate inspired by analogous ideas of
Ambrosio, Lecumberry, and Maniglia, Crippa and De Lellis in the Lagrangian
case.
|
1411.0451v1
|
2015-02-07
|
Landau Damping in a Mixture of Bose and Fermi Superfluids
|
We study the Landau damping in Bose-Fermi superfluid mixture at finite
temperature. We find that at low temperature, the Landau damping rate will be
exponentially suppressed at both the BCS side and the BEC side of Fermi
superfluid. The momentum dependence of the damping rate is obtained, and it is
quite different from the BCS side to the BEC side. The relations between our
result and collective mode experiment in the recently realized Bose-Fermi
superfluid mixture are also discussed.
|
1502.02116v1
|
2015-03-20
|
Applying a formula for generator redispatch to damp interarea oscillations using synchrophasors
|
If an interarea oscillatory mode has insufficient damping, generator
redispatch can be used to improve its damping. We explain and apply a new
analytic formula for the modal sensitivity to rank the best pairs of generators
to redispatch. The formula requires some dynamic power system data and we show
how to obtain that data from synchrophasor measurements. The application of the
formula to damp interarea modes is explained and illustrated with interarea
modes of the New England 10-machine power system.
|
1503.06144v2
|
2016-01-21
|
Codeword Stabilized Quantum Codes for Asymmetric Channels
|
We discuss a method to adapt the codeword stabilized (CWS) quantum code
framework to the problem of finding asymmetric quantum codes. We focus on the
corresponding Pauli error models for amplitude damping noise and phase damping
noise. In particular, we look at codes for Pauli error models that correct one
or two amplitude damping errors. Applying local Clifford operations on graph
states, we are able to exhaustively search for all possible codes up to length
$9$. With a similar method, we also look at codes for the Pauli error model
that detect a single amplitude error and detect multiple phase damping errors.
Many new codes with good parameters are found, including nonadditive codes and
degenerate codes.
|
1601.05763v1
|
2016-02-08
|
On Boundary Damped Inhomogeneous Timoshenko Beams and Related Problems
|
We consider the model equations for the Timoshenko beam as a first order
system in the framework of evolutionary equations. The focus is on boundary
damping, which is implemented as a dynamic boundary condition. A change of
material laws allows to include a large class of cases of boundary damping. By
choosing a particular material law, it is shown that the first order approach
to Sturm-Liouville problems with boundary damping is also covered.
|
1602.02521v1
|
2016-02-13
|
Diffusion phenomena for the wave equation with space-dependent damping in an exterior domain
|
In this paper, we consider the asymptotic behavior of solutions to the wave
equation with space-dependent damping in an exterior domain. We prove that when
the damping is effective, the solution is approximated by that of the
corresponding heat equation as time tends to infinity. Our proof is based on
semigroup estimates for the corresponding heat equation and weighted energy
estimates for the damped wave equation. The optimality of the decay late for
solutions is also established.
|
1602.04318v1
|
2016-02-29
|
Robust quantum state recovery from amplitude damping within a mixed states framework
|
Due to the interaction with the environment, a quantum state is subjected to
decoherence which becomes one of the biggest problems for practical quantum
computation. Amplitude damping is one of the most important decoherence
processes. Here, we show that general two-qubit mixed states undergoing an
amplitude damping can be almost completely restored using a reversal procedure.
This reversal procedure through CNOT and Hadamard gates, could also protect the
entanglement of two-qubit mixed states, when it undergoes general amplitude
damping. Moreover, in the presence of uncertainty in the underlying system, we
propose a robust recovering method with optimal characteristics of the problem.
|
1602.08865v1
|
2016-05-23
|
Large time behaivor of global solutions to nonlinear wave equations with frictional and viscoelastic damping terms
|
In this paper, we study the Cauchy problem for a nonlinear wave equation with
frictional and viscoelastic damping terms. As is pointed out by [8], in this
combination, the frictional damping term is dominant for the viscoelastic one
for the global dynamics of the linear equation. In this note we observe that if
the initial data is small, the frictional damping term is again dominant even
in the nonlinear equation case. In other words, our main result is diffusion
phenomena: the solution is approximated by the heat kernel with a suitable
constant. Our proof is based on several estimates for the corresponding linear
equations.
|
1605.07232v1
|
2016-07-21
|
Protecting and enhancing spin squeezing under decoherence using weak measurement
|
We propose an efficient method to protect spin squeezing under the action of
amplitude-damping, depolarizing and phase-damping channels based on measurement
reversal from weak measurement, and consider an ensemble of N independent
spin-1/2 particles with exchange symmetry. We find that spin squeezing can be
enhanced greatly under three different decoherence channels and spin-squeezing
sudden death (SSSD) can be avoided undergoing amplitude damping and
phase-damping channels.
|
1607.06530v2
|
2016-09-05
|
Remarks on an elliptic problem arising in weighted energy estimates for wave equations with space-dependent damping term in an exterior domain
|
This paper is concerned with weighted energy estimates and diffusion
phenomena for the initial-boundary problem of the wave equation with
space-dependent damping term in an exterior domain. In this analysis, an
elliptic problem was introduced by Todorova and Yordanov. This attempt was
quite useful when the coefficient of the damping term is radially symmetric. In
this paper, by modifying their elliptic problem, we establish weighted energy
estimates and diffusion phenomena even when the coefficient of the damping term
is not radially symmetric.
|
1609.01063v2
|
2016-11-16
|
Finite-orbit-width effects on the geodesic acoustic mode in the toroidally rotating tokamak plasma
|
The Landau damping of geodesic acoustic mode (GAM) in a torodial rotating
tokamak plasma is analytically investigated by taking into account the
finite-orbit-width (FOW) resonance effect to the 3rd order. The analytical
result is shown to agree well with the numerical solution. The dependence of
the damping rate on the toroidal Mach number $M$ relies on $k_r \rho_i$. For
sufficiently small $k_r \rho_i$, the damping rate monotonically decreases with
$M$. For relatively large $k_r \rho_i$, the damping rate increases with $M$
until approaching the maximum and then decreases with $M$.
|
1611.05168v1
|
2017-03-09
|
Long-time dynamics of the strongly damped semilinear plate equation in $\mathbb{R}^{n}$
|
We investigate the initial-value problem for the semilinear plate equation
containing localized strong damping, localized weak damping and nonlocal
nonlinearity. We prove that if nonnegative damping coefficients are strictly
positive almost everywhere in the exterior of some ball and the sum of these
coefficients is positive a.e. in $%
\mathbb{R}
^{n}$, then the semigroup generated by the considered problem possesses a
global attractor in $H^{2}\left(
\mathbb{R}
^{n}\right) \times L^{2}\left(
\mathbb{R}
^{n}\right) $. We also establish boundedness of this attractor in $
H^{3}\left(
\mathbb{R}
^{n}\right) \times H^{2}\left(
\mathbb{R} ^{n}\right) $.
|
1703.03485v2
|
2017-04-21
|
The Effects of Rolling Deformation and Annealing Treatment on Damping Capacity of 1200 Aluminium Alloy
|
Annealing treatment is an important step of rolling deformation that
contributes to microstructural evolution and leads to the significant changes
in damping capacity. Damping capacities were analyzed in the parallel to
rolling direction at 1 and 10 Hz respectively. It was found that severe plastic
deformation at 40 percent reduction has lower damping capacity compared to that
of 30 percent and 20 percent reductions respectively. The microstructural
results show that the grains of as rolled alloys were changed to almost
equiaxed structures after a rolling reduction at 40 percent reduction.
|
1704.07362v1
|
2017-07-12
|
Isolated resonances and nonlinear damping
|
We analyze isolated resonance curves (IRCs) in a single-degree-of-freedom
system with nonlinear damping. The adopted procedure exploits singularity
theory in conjunction with the harmonic balance method. The analysis unveils a
geometrical connection between the topology of the damping force and IRCs.
Specifically, we demonstrate that extremas and zeros of the damping force
correspond to the appearance and merging of IRCs.
|
1707.03561v2
|
2017-07-25
|
Best exponential decay rate of energy for the vectorial damped wave equation
|
The energy of solutions of the scalar damped wave equation decays uniformly
exponentially fast when the geometric control condition is satisfied. A theorem
of Lebeau [leb93] gives an expression of this exponential decay rate in terms
of the average value of the damping terms along geodesics and of the spectrum
of the infinitesimal generator of the equation. The aim of this text is to
generalize this result in the setting of a vectorial damped wave equation on a
Riemannian manifold with no boundary. We obtain an expression analogous to
Lebeau's one but new phenomena like high frequency overdamping arise in
comparison to the scalar setting. We also prove a necessary and sufficient
condition for the strong stabilization of the vectorial wave equation.
|
1707.07893v1
|
2017-08-20
|
Radiation Damping of a Polarizable Particle
|
A polarizable body moving in an external electromagnetic field will slow
down. This effect is referred to as radiation damping and is analogous to
Doppler cooling in atomic physics. Using the principles of special relativity
we derive an expression for the radiation damping force and find that it solely
depends on the scattered power. The cooling of the particle's center-of-mass
motion is balanced by heating due to radiation pressure shot noise, giving rise
to an equilibrium that depends on the ratio of the field's frequency and the
particle's mass. While damping is of relativistic nature heating has it's roots
in quantum mechanics.
|
1708.06628v1
|
2017-09-13
|
Energy decay for the Klein-Gordon equation with highly oscillating damping
|
We consider the free Klein-Gordon equation with periodic damping. We show on
this simple model that if the usual geometric condition holds then the decay of
the energy is uniform with respect to the oscillations of the damping, and in
particular the size of the derivatives do not play any role. We also show that
without geometric condition the polynomial decay of the energy is even slightly
better for a highly oscillating damping. To prove these estimates we provide a
parameter dependent version of well known results of semigroup theory.
|
1709.04197v1
|
2017-11-01
|
Analysis of A Splitting Scheme for Damped Stochastic Nonlinear Schrödinger Equation with Multiplicative Noise
|
In this paper, we investigate the damped stochastic nonlinear
Schr\"odinger(NLS) equation with multiplicative noise and its splitting-based
approximation. When the damped effect is large enough, we prove that the
solutions of the damped stochastic NLS equation and the splitting scheme are
exponential stable and possess some exponential integrability.
These properties lead that the strong order of the scheme is $\frac 12$ and
independent of time. Meanwhile, we analyze the regularity of the Kolmogorov
equation with respect to the equation. As a consequence, the weak order of the
scheme is shown to be twice the strong order and independent of time.
|
1711.00516v2
|
2017-12-31
|
Stabilization of the weakly coupled wave-plate system with one internal damping
|
This paper is addressed to a stabilization problem of a system coupled by a
wave and a Euler-Bernoulli plate equation. Only one equation is supposed to be
damped. Under some assumption about the damping and the coupling terms, it is
shown that sufficiently smooth solutions of the system decay logarithmically at
infinity without any geometric conditions on the effective damping domain. The
proofs of these decay results rely on the interpolation inequalities for the
coupled elliptic-parabolic systems and make use of the estimate of the
resolvent operator for the coupled system. The main tools to derive the desired
interpolation inequalities are global Carleman estimates.
|
1801.00232v1
|
2018-05-10
|
Dynamics of coherence-induced state ordering under Markovian channels
|
We study the dynamics of coherence-induced state ordering under incoherent
channels, particularly four specific Markovian channels: $-$ amplitude damping
channel, phase damping channel, depolarizing channel and bit flit channel for
single-qubit states. We show that the amplitude damping channel, phase damping
channel, and depolarizing channel do not change the coherence-induced state
ordering by $l_1$ norm of coherence, relative entropy of coherence, geometric
measure of coherence, and Tsallis relative $\alpha$-entropies, while the bit
flit channel does change for some special cases.
|
1805.03898v1
|
2018-08-19
|
Sharp lifespan estimates of blowup solutions to semilinear wave equations with time-dependent effective damping
|
We consider the initial value problem for the semilinear wave equation with
time-dependent effective damping. The interest is the behavior of lifespan of
solutions in view of the asymptotic profile of the damping as $t\to \infty$.
The result of this paper is the sharp lifespan estimates of blowup solutions
for general time-dependent damping including threshold cases between effective
and overdamping.
|
1808.06189v2
|
2018-09-05
|
Damping estimates for oscillatory integral operators with real-analytic phases and its applications
|
In this paper, we investigate sharp damping estimates for a class of one
dimensional oscillatory integral operators with real-analytic phases. By
establishing endpoint estimates for suitably damped oscillatory integral
operators, we are able to give a new proof of the sharp $L^p$ estimates which
have been proved by Xiao in Endpoint estimates for one-dimensional oscillatory
integral operators, \emph{Advances in Mathematics}, \textbf{316}, 255-291
(2017). The damping estimates obtained in this paper are of independent
interest.
|
1809.01298v2
|
2018-09-26
|
Global Attractor For Weakly Damped, Forced Mkdv Equation Below Energy Space
|
We prove the existence of the global attractor in $ \dot H^s$, $s > 11/12$
for the weakly damped and forced mKdV on the one dimensional torus. The
existence of global attractor below the energy space has not been known, though
the global well-posedness below the energy space is established. We directly
apply the I-method to the damped and forced mKdV, because the Miura
transformation does not work for the mKdV with damping and forcing terms. We
need to make a close investigation into the trilinear estimates involving
resonant frequencies, which are different from the bilinear estimates
corresponding to the KdV.
|
1809.09787v1
|
2018-10-03
|
Damped Oscillator with delta-kicked frequency in probability representation of quantum mechanic
|
We obtain the tomogram of squeezed correlated states of a quantum parametric
damped oscillator in an explicit form. We study the damping within the
framework of the Caldirola--Kanai model and chose the parametric excitation in
the form of a very short pulse simulated by a delta-kick of frequency; the
squeezing phenomenon is reviewed. The cases of strong and weak damping are
investigated.
|
1810.01672v1
|
2018-10-26
|
Drastic Reduction of Plasmon Damping in Two-Dimensional Electron Disks
|
The plasmon damping has been investigated using resonant microwave absorption
of two-dimensional electrons in disks with different diameters. We have found
an unexpected drastic reduction of the plasmon damping in the regime of strong
retardation. This finding implies large delocalization of retarded plasmon
field outside the plane of the two-dimensional electron system. A universal
relation between the damping of plasmon polariton waves and retardation
parameter is reported.
|
1811.01040v1
|
2019-01-05
|
Cauchy problem for thermoelastic plate equations with different damping mechanisms
|
In this paper we study Cauchy problem for thermoelastic plate equations with
friction or structural damping in $\mathbb{R}^n$, $n\geq1$, where the heat
conduction is modeled by Fourier's law. We explain some qualitative properties
of solutions influenced by different damping mechanisms. We show which damping
in the model has a dominant influence on smoothing effect, energy estimates,
$L^p-L^q$ estimates not necessary on the conjugate line, and on diffusion
phenomena. Moreover, we derive asymptotic profiles of solutions in a framework
of weighted $L^1$ data. In particular, sharp decay estimates for lower bound
and upper bound of solutions in the $\dot{H}^s$ norm ($s\geq0$) are shown.
|
1901.01423v2
|
2019-03-04
|
Damping of cosmological tensor modes in Horndeski theories after GW170817
|
This paper investigates the propagation of cosmological gravitational waves
interacting with free-streaming neutrinos within the context of Horndeski
theories of gravity constrained by the detection of GW170817. We apply the
theory of cosmological perturbations to explicitly derive the
Einstein-Boltzmann equation for the damped propagation of first-order
transverse traceless gravitational waves. In contrast to general relativity, we
argue that modified gravity can give rise to non-vanishing free-streaming
damping effects during the cosmological matter dominated era. We also provide
an analytic formula for the main multipole order with which modified gravity
and free-streaming neutrinos damp the variety of tensor correlation functions
of the cosmic microwave background.
|
1903.01502v2
|
2019-04-24
|
On the Energy Decay Rate of the Fractional Wave Equation on $\mathbb{R}$ with Relatively Dense Damping
|
We establish upper bounds for the decay rate of the energy of the damped
fractional wave equation when the averages of the damping coefficient on all
intervals of a fixed length are bounded below. If the power of the fractional
Laplacian, $s$, is between 0 and 2, the decay is polynomial. For $s \ge 2$, the
decay is exponential. Second, we show that our assumption on the damping is
necessary for the energy to decay exponentially.
|
1904.10946v3
|
2019-08-22
|
Damping of the Anderson-Bogolyubov mode by spin and mass imbalance in Fermi mixtures
|
We study the temporally nonlocal contributions to the gradient expansion of
the pair fluctuation propagator for spin- and mass-imbalanced Fermi mixtures.
These terms are related to damping processes of sound-like
(Anderson-Bogolyubov) collective modes and are relevant for the structure of
the complex pole of the pair fluctuation propagator. We derive conditions under
which damping occurs even at zero temperature for large enough mismatch of the
Fermi surfaces. We compare our analytical results with numerically computed
damping rates of the Anderson-Bogolyubov mode.
|
1908.08559v2
|
2019-11-05
|
On the Smallness Condition in Linear Inviscid Damping: Monotonicity and Resonance Chains
|
We consider the linearized Euler equations around a smooth, bilipschitz shear
profile $U(y)$ on $\mathbb{T}_L \times \mathbb{R}$. We construct an explicit
flow which exhibits linear inviscid damping for $L$ sufficiently small, but for
which damping fails if $L$ is large. In particular, similar to the instability
results for convex profiles for a shear flow being bilipschitz is not
sufficient for linear inviscid damping to hold. Instead of an eigenvalue-based
argument the underlying mechanism here is shown to be based on a new cascade of
resonances moving to higher and higher frequencies in $y$, which is distinct
from the echo chain mechanism in the nonlinear problem.
|
1911.02066v1
|
2020-01-02
|
On Echo Chains in Landau damping: Self-similar Solutions and Gevrey 3 as a Linear Stability Threshold
|
We show that the linearized Vlasov-Poisson equations around self-similar
non-homogeneous states near zero contain the full plasma echo mechanism,
yielding Gevrey 3 as a critical stability class. Moreover, here Landau damping
may persist despite blow-up: We construct a critical Gevrey regularity class in
which the force field converges in $L^2$. Thus, on the one hand, the physical
phenomenon of Landau damping holds. On the other hand, the density diverges to
infinity in Sobolev regularity. Hence, ``strong damping'' cannot hold.
|
2001.00513v1
|
2020-01-21
|
Pseudospectra of the damped wave equation with unbounded damping
|
We analyze pseudospectra of the generator of the damped wave equation with
unbounded damping. We show that the resolvent norm diverges as $\Re z \to -
\infty$. The highly non-normal character of the operator is a robust effect
preserved even when a strong potential is added. Consequently, spectral
instabilities and other related pseudospectral effects are present.
|
2001.07767v1
|
2020-02-09
|
The damped wave equation with singular damping
|
We analyze the spectral properties and peculiar behavior of solutions of a
damped wave equation on a finite interval with a singular damping of the form
$\alpha/x$, $\alpha>0$. We establish the exponential stability of the semigroup
for all positive $\alpha$, and determine conditions for the spectrum to consist
of a finite number of eigenvalues. As a consequence, we fully characterize the
set of initial conditions for which there is extinction of solutions in finite
time. Finally, we propose two open problems related to extremal decay rates of
solutions.
|
2002.03440v1
|
2020-03-12
|
Optimal nonlinear damping control of second-order systems
|
Novel nonlinear damping control is proposed for the second-order systems. The
proportional output feedback is combined with the damping term which is
quadratic to the output derivative and inverse to the set-point distance. The
global stability, passivity property, and convergence time and accuracy are
demonstrated. Also the control saturation case is explicitly analyzed. The
suggested nonlinear damping is denoted as optimal since requiring no design
additional parameters and ensuring a fast convergence, without transient
overshoots for a non-saturated and one transient overshoot for a saturated
control configuration.
|
2003.05670v3
|
2020-06-24
|
Stability of a star-shaped network with local Kelvin-Voigt damping and non-smooth coefficient at interface
|
In this paper, we study the stability problem of a star-shaped network of
elastic strings with a local Kelvin-Voigt damping. Under the assumption that
the damping coefficients have some singularities near the transmission point,
we prove that the semigroup corresponding to the system is polynomially stable
and the decay rates depends on the speed of the degeneracy. This result
improves the decay rate of the semigroup associated to the system on an earlier
result of Z.~Liu and Q.~Zhang in \cite{LZ} involving the wave equation with
local Kelvin-Voigt damping and non-smooth coefficient at interface.
|
2006.14949v1
|
2020-11-06
|
A generalized finite element method for the strongly damped wave equation with rapidly varying data
|
We propose a generalized finite element method for the strongly damped wave
equation with highly varying coefficients. The proposed method is based on the
localized orthogonal decomposition introduced and is designed to handle
independent variations in both the damping and the wave propagation speed
respectively. The method does so by automatically correcting for the damping in
the transient phase and for the propagation speed in the steady state phase.
Convergence of optimal order is proven in $L_2(H^1)$-norm, independent of the
derivatives of the coefficients. We present numerical examples that confirm the
theoretical findings.
|
2011.03311v1
|
2020-11-11
|
Reduction of back switching by large damping ferromagnetic material
|
Recent studies on magnetization dynamics induced by spin-orbit torque have
revealed a weak dependence of the critical current for magnetization switching
on the damping constant of a ferromagnetic free layer. This study, however,
reveals that the damping constant nevertheless plays a key role in
magnetization switching induced by spin-orbit torque. An undesirable switching,
returning to an initial state, named as back switching, occurs in a ferromagnet
with an easy axis parallel to the current direction. Numerical and theoretical
analyses reveal that back switching is strongly suppressed when the damping
constant of the ferromagnet is large.
|
2011.05566v1
|
2020-12-28
|
Nonlinear modal analysis of nonconservative systems: Extension of the periodic motion concept
|
As the motions of nonconservative autonomous systems are typically not
periodic, the definition of nonlinear modes as periodic motions cannot be
applied in the classical sense. In this paper, it is proposed 'make the motions
periodic' by introducing an additional damping term of appropriate sign and
magnitude. It is shown that this generalized definition is particularly suited
to reflect the periodic vibration behavior induced by harmonic external forcing
or negative linear damping. In a large range, the energy dependence of modal
frequency, damping ratio and stability is reproduced well. The limitation to
isolated or weakly-damped modes is discussed.
|
2101.00949v1
|
2021-02-28
|
Stability for an inverse source problem of the damped biharmonic plate equation
|
This paper is concerned with the stability of the inverse source problem for
the damped biharmonic plate equation in three dimensions. The stability
estimate consists of the Lipschitz type data discrepancy and the high frequency
tail of the source function, where the latter decreases as the upper bound of
the frequency increases. The stability also shows exponential dependence on the
constant damping coefficient. The analysis employs Carleman estimates and time
decay estimates for the damped plate wave equation to obtain an exact
observability bound and depends on the study of the resonance-free region and
an upper bound of the resolvent of the biharmonic operator with respect to the
complex wavenumber.
|
2103.00461v1
|
2021-04-12
|
Lp-asymptotic stability of 1D damped wave equations with localized and linear damping
|
In this paper, we study the $L^p$-asymptotic stability of the one-dimensional
linear damped wave equation with Dirichlet boundary conditions in $[0,1]$, with
$p\in (1,\infty)$. The damping term is assumed to be linear and localized to an
arbitrary open sub-interval of $[0,1]$. We prove that the semi-group
$(S_p(t))_{t\geq 0}$ associated with the previous equation is well-posed and
exponentially stable. The proof relies on the multiplier method and depends on
whether $p\geq 2$ or $1<p<2$.
|
2104.05679v1
|
2021-05-13
|
Sharp Polynomial Decay for Waves Damped from the Boundary in Cylindrical Waveguides
|
We study the decay of global energy for the wave equation with H\"older
continuous damping placed on the $C^{1,1}$-boundary of compact and non-compact
waveguides with star-shaped cross-sections. We show there is sharp
$t^{-1/2}$-decay when the damping is uniformly bounded from below on the
cylindrical wall of product cylinders where the Geometric Control Condition is
violated. On non-product cylinders, we also show that there is $t^{-1/3}$-decay
when the damping is uniformly bounded from below on the cylindrical wall.
|
2105.06566v1
|
2021-06-02
|
Stabilisation of the generalised Rao-Nakra beam by partial viscous damping
|
In this paper, we consider the stabilization of the generalized Rao-Nakra
beam equation, which consists of four wave equations for the longitudinal
displacements and the shear angle of the top and bottom layers and one
Euler-Bernoulli beam equation for the transversal displacement. Dissipative
mechanism are provided through viscous damping for two displacements. The
location of the viscous damping are divided into two groups, characterized by
whether both of the top and bottom layers are directly damped or otherwise.
Each group consists of three cases. We obtain the necessary and sufficient
conditions for the cases in group two to be strongly stable. Furthermore,
polynomial stability of certain orders are proved. The cases in group one are
left for future study
|
2106.01189v1
|
2021-09-01
|
Vibration damping platform for cavity quantum-electrodynamics experiments
|
We present a mechanical platform with enhanced vibration damping properties
for cavity quantum-electrodynamics experiments. It is based on a composite
design that combines a soft, vibration-damping core with a rigid shell
maintaining optical alignment. It passively damps the vibrations generated by
piezoelectric actuators controlling the mirror positions. The mechanical
resonances of the platform, which lead to a length change of the cavity are
efficiently suppressed up to 100 kHz. Our platform is ultra-high vacuum
compatible and can be used in most applications, in particular where long
cavities and optical access to the cavity center are required.
|
2109.00439v1
|
2021-09-05
|
Existence of a generalized polynomial attractor for the wave equation with nonlocal weak damping, anti-damping and critical nonlinearity
|
In this paper, we first establish a criterion based on contractive function
for the existence of polynomial attractors. This criterion only involves some
rather weak compactness associated with the repeated limit inferior and
requires no compactness, which makes it suitable for critical cases. Then by
this abstract theorem, we verify the existence of a polynomial attractor and
estimate its attractive speed for the wave equation with nonlocal weak damping,
anti-damping and critical nonlinearity.
|
2109.01967v2
|
2021-11-29
|
Stabilization of coupled wave equations with viscous damping on cylindrical and non-regular domains: Cases without the geometric control condition
|
In this paper, we investigate the direct and indirect stability of locally
coupled wave equations with local viscous damping on cylindrical and
non-regular domains without any geometric control condition. If only one
equation is damped, we prove that the energy of our system decays polynomially
with the rate $t^{-\frac{1}{2}}$ if the two waves have the same speed of
propagation, and with rate $t^{-\frac{1}{3}}$ if the two waves do not propagate
at the same speed. Otherwise, in case of two damped equations, we prove a
polynomial energy decay rate of order $t^{-1}$.
|
2111.14554v1
|
2022-01-25
|
Linear pair creation damping of high frequency plasma oscillation
|
We have studied the linear dispersion relation for Langmuir waves in plasmas
of very high density, based on the Dirac-Heisenberg-Wigner formalism. The
vacuum contribution to the physical observables leads to ultra-violet
divergences, that are removed by a charge renormalization. The remaining vacuum
contribution is small, and is in agreement with previously derived expressions
for the time-dependent vacuum polarization. The main new feature of the theory
is a damping mechanism similar to Landau damping, but where the plasmon energy
give rise to creation of electron-positron pairs. The dependence of the damping
rate (pair-creation rate) on wave-number, temperature, and density is analyzed.
Finally, the analytical results of linearized theory are compared.
|
2201.10370v1
|
2022-03-13
|
Continuum damping of topologically-protected edge modes at the boundary of a magnetized plasma
|
Recent extension of the topological ideas to continuous systems with broken
time-reversal symmetry, such as magnetized plasmas, provides new insights into
the nature of scattering-free topologically-protected surface plasma waves
(TSPWs). We demonstrate a unique characteristic of TSPWs propagating above the
electron cyclotron frequency: their collisionless damping via coupling to the
continuum of resonant modes localized inside a smooth plasma-vacuum interface.
Damped TSPWs retain their unidirectional nature and robustness against
backscattering. When sheared magnetic field creates a boundary between damped
and undamped TSPWs, the two refract into each other without reflections
|
2203.06693v2
|
2022-04-21
|
On scattering and damping of Toroidal Alfven eigenmode by drift wave turbulence
|
We demonstrate analytically that, in toroidal plasmas, scattering by drift
wave turbulence could lead to appreciable damping of toroidal Alfven eigenmodes
via generation of short-wavelength electron Landau damped kinetic Alfven waves.
A corresponding analytic expression of the damping rate is derived, and found
to be, typically, comparable to the linear drive by energetic particles. The
implications of this novel mechanism on the transport and heating processes in
burning plasmas are also discussed.
|
2204.09876v1
|
2022-10-30
|
Intrinsic polynomial squeezing for Balakrishnan-Taylor beam models
|
We explore the energy decay properties related to a model in extensible beams
with the so-called energy damping. We investigate the influence of the
nonloncal damping coefficient in the stability of the model. We prove, for the
first time, that the corresponding energy functional is squeezed by
polynomial-like functions involving the power of the damping coefficient, which
arises intrinsically from the Balakrishnan-Taylor beam models. As a
consequence, it is shown that such models with nonlocal energy damping are
never exponentially stable in its essence.
|
2210.16931v1
|
2023-02-13
|
Damping of gravitational waves in f(R) gravity
|
We study the damping of $f(R)$ gravitational waves by matter in flat
spacetime and in expanding universe. In the former case, we find that the
Landau damping of scalar mode in $f(R)$ theory exists, while that of the tensor
mode in general relativity does not; we also present the viscosity coefficients
and dispersion relations of the two modes. In the later case, we investigate
the evolution of tensor and scalar modes in Friedmann-Robertson-Walker (FRW)
cosmology with a matter distribution; by considering the case of $f(R)=R+\al
R^2$, we analysis the influence of parameter $\al$ on wave damping,and put
restrictions on its magnitude.
|
2302.06402v2
|
2023-07-11
|
Global smooth solution for the 3D generalized tropical climate model with partial viscosity and damping
|
The three-dimensional generalized tropical climate model with partial
viscosity and damping is considered in this paper. Global well-posedness of
solutions of the three-dimensional generalized tropical climate model with
partial viscosity and damping is proved for $\alpha\geq\frac{3}{2}$ and
$\beta\geq4$. Global smooth solution of the three-dimensional generalized
tropical climate model with partial viscosity and damping is proved in
$H^s(\mathbb R^3)$ $(s>2)$ for $\alpha\geq\frac{3}{2}$ and $4\leq\beta\leq5$.
|
2307.05145v3
|
2023-08-07
|
Reconstruction of the initial data from the solutions of damped wave equations
|
In this paper, we consider two types of damped wave equations: the weakly
damped equation and the strongly damped equation and show that the initial
velocity from the solution on the unit sphere. This inverse problem is related
to Photoacoustic Tomography (PAT), a hybrid medical imaging technique. PAT is
based on generating acoustic waves inside of an object of interest and one of
the mathematical problem in PAT is reconstructing the initial velocity from the
solution of the wave equation measured on the outside of object. Using the
spherical harmonics and spectral theorem, we demonstrate a way to recover the
initial velocity.
|
2308.03362v1
|
2023-09-26
|
Sharp conditions for exponential and non-exponential uniform stabilization of the time dependent damped wave equation
|
It is classical that uniform stabilization of solutions to the damped wave
equation is equivalent to the geometric control condition The author previously
showed that, when the damping depends on time, a generalization of the
geometric control condition implies uniform stabilization at an exponential
rate. In this paper, it is shown that this generalization of the geometric
control condition is necessary for uniform stabilization at an exponential
rate. Furthermore, when the damping does not satisfy this generalization, and
has some additional structure, upper and lower bounds on non-exponential
uniform stabilization are computed. The qualitative behavior of these upper and
lower bounds coincide.
|
2309.15005v1
|
2023-10-19
|
The damped focusing cubic wave equation on a bounded domain
|
For the focusing cubic wave equation on a compact Riemannian manifold of
dimension $3$, the dichotomy between global existence and blow-up for solutions
starting below the energy of the ground state is known since the work of Payne
and Sattinger. In the case of a damped equation, we prove that the dichotomy
between global existence and blow-up still holds. In particular, the damping
does not prevent blow-up. Assuming that the damping satisfies the geometric
control condition, we then prove that any global solution converges to a
stationary solution along a time sequence, and that global solutions below the
energy of the ground state can be stabilised, adapting the proof of a similar
result in the defocusing case.
|
2310.12644v2
|
2024-04-03
|
Damping Reveals Hidden Dimensions in Elastic Metastructures Through Induced Transparency
|
Damping typically results in attenuation of vibrations and elastic wave
propagation in mechanical systems. Contrary to this conventional understanding,
we demonstrate experimentally and explain theoretically the revival of an
elastic wave transmitted through a periodic metastructure when a weak
non-Hermitian defect (damping mechanism) induces violation of time-reversal
symmetry. Damping alters the nature of the system's resonant modes, instigating
interference in the scattering field. This leads to transmission revival,
revealing the presence of hidden modes which are otherwise masked by the
symmetry. Our findings offer an innovative approach for designing
dissipation-driven switches and controllers and non-destructive structural
health monitoring systems.
|
2404.02979v1
|
1997-06-30
|
Damped Lyman Alpha Systems at High Redshift and Models of Protogalactic Disks
|
We employ observationally determined intrinsic velocity widths and column
densities of damped Lyman-alpha systems at high redshift to investigate the
distribution of baryons in protogalaxies within the context of a standard cold
dark matter model. We proceed under the assumption that damped Lyman alpha
systems represent a population of cold, rotationally supported, protogalactic
disks and that the abundance of protogalactic halos is well approximated by a
cold dark matter model with critical density and vanishing cosmological
constant. Using conditional cross sections to observe a damped system with a
given velocity width and column density, we compare observationally inferred
velocity width and column density distributions to the corresponding
theoretically determined distributions for a variety of disk parameters and CDM
normalizations. In general, we find that the observations can not be reproduced
by the models for most disk parameters and CDM normalizations. Whereas the
column density distribution favors small disks with large neutral gas fraction,
the velocity width distribution favors large and thick disks with small neutral
gas fraction. The possible resolutions of this problem in the context of this
CDM model may be: (1) an increased contribution of rapidly rotating disks
within massive dark matter halos to damped Lyman-alpha absorption or (2) the
abandoning of simple disk models within this CDM model for damped Lyman-alpha
systems at high redshift. Here the first possibility may be achieved by
supposing that damped Lya system formation only occurs in halos with fairly
large circular velocities and the second possibility may result from a large
contribution of mergers and double-disks to damped Lya absorption at high
redshift.
|
9706290v1
|
2000-03-16
|
Non-existence of radiation damping of gravitational motions
|
A rigorous, non-perturbative proof that there is no radiation damping of
gravitational motions.
|
0003230v1
|
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