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2023-10-30
Beliaev damping in Bose gas
According to the Bogoliubov theory the low energy behaviour of the Bose gas at zero temperature can be described by non-interacting bosonic quasiparticles called phonons. In this work the damping rate of phonons at low momenta, the so-called Beliaev damping, is explained and computed with simple arguments involving the...
2310.20070v1
2023-11-25
Energy scattering for the unsteady damped nonlinear Schrodinger equation
We investigate the large time behavior of the solutions to the nonlinear focusing Schr\"odinger equation with a time-dependent damping in the energy sub-critical regime. Under non classical assumptions on the unsteady damping term, we prove some scattering results in the energy space.
2311.14980v2
2017-10-18
Direct detection of metal-insulator phase transitions using the modified Backus-Gilbert method
The detection of the (semi)metal-insulator phase transition can be extremely difficult if the local order parameter which characterizes the ordered phase is unknown.In some cases, it is even impossible to define a local order parameter: the most prominent example of such system is the spin liquid state. This state was ...
1710.06675v1
2020-09-14
Bounds and Code Constructions for Partially Defect Memory Cells
This paper considers coding for so-called partially stuck memory cells. Such memory cells can only store partial information as some of their levels cannot be used due to, e.g., wear out. First, we present a new code construction for masking such partially stuck cells while additionally correcting errors. This construc...
2009.06512v3
2002-02-21
Mechanisms of spin-polarized current-driven magnetization switching
The mechanisms of the magnetization switching of magnetic multilayers driven by a current are studied by including exchange interaction between local moments and spin accumulation of conduction electrons. It is found that this exchange interaction leads to two additional terms in the Landau-Lifshitz-Gilbert equation: a...
0202363v1
2005-10-30
Domain instability during precessional magnetization reversal
Spin wave equations in the non-equilibrium precessing state of a ferromagnetic system are found. They show a spin-wave instability towards growing domains of stable magnetization. Precession of the uniform magnetization mode is described by the Landau Lifshitz equation with the exponentially growing in time effective G...
0510817v1
1991-12-02
Perturbations of a Stringy Black Hole
We extend the three dimensional stringy black hole of Horne and Horowitz to four dimensions. After a brief discussion of the global properties of the metric, we discuss the stability of the background with respect to small perturbations, following the methods of Gilbert and of Chandrasekhar. The potential for axial per...
9112001v2
1996-05-06
Finitely presented subgroups of automatic groups and their isoperimetric functions
We describe a general technique for embedding certain amalgamated products into direct products. This technique provides us with a way of constructing a host of finitely presented subgroups of automatic groups which are not even asynchronously automatic. We can also arrange that such subgroups satisfy, at best, an expo...
9605201v1
1999-07-22
Constructing Hyperbolic Manifolds
In this paper we show how to obtain representations of Coxeter groups acting on H^n to certain classical groups. We determine when the kernel of such a representation is torsion-free and thus the quotient a hyperbolic n-manifold.
9907139v1
2002-02-06
Quaternionic equation for electromagnetic fields in inhomogeneous media
We show that the Maxwell equations for arbitrary inhomogeneous media are equivalent to a single quaternionic equation which can be considered as a generalization of the Vekua equation for generalized analytic functions.
0202010v1
1996-02-29
Error Correction in Quantum Communication
We show how procedures which can correct phase and amplitude errors can be directly applied to correct errors due to quantum entanglement. We specify general criteria for quantum error correction, introduce quantum versions of the Hamming and the Gilbert-Varshamov bounds and comment on the practical implementation of q...
9602022v1
2007-05-19
Log-periodic drift oscillations in self-similar billiards
We study a particle moving at unit speed in a self-similar Lorentz billiard channel; the latter consists of an infinite sequence of cells which are identical in shape but growing exponentially in size, from left to right. We present numerical computation of the drift term in this system and establish the logarithmic pe...
0705.2790v1
2008-04-26
Asymptotic Bound on Binary Self-Orthogonal Codes
We present two constructions for binary self-orthogonal codes. It turns out that our constructions yield a constructive bound on binary self-orthogonal codes. In particular, when the information rate R=1/2, by our constructive lower bound, the relative minimum distance \delta\approx 0.0595 (for GV bound, \delta\approx ...
0804.4194v1
2008-11-14
Scott and Swarup's regular neighbourhood as a tree of cylinders
Let G be a finitely presented group. Scott and Swarup have constructed a canonical splitting of G which encloses all almost invariant sets over virtually polycyclic subgroups of a given length. We give an alternative construction of this regular neighbourhood, by showing that it is the tree of cylinders of a JSJ splitt...
0811.2389v1
2009-05-04
Self-organized quantum transitions in a spin-electron coupled system
We investigate quantum dynamics of the excited electronic states in the double-exchange model at half-filling by solving coupled equations for the quantum evolution of electrons and Landau-Lifshits-Gilbert equation for classical spins. The non-adiabatic quantum transitions driving the relaxation are coordinated through...
0905.0311v1
2009-05-04
Oscillating Ponomarenko dynamo in the highly conducting limit
This paper considers dynamo action in smooth helical flows in cylindrical geometry, otherwise known as Ponomarenko dynamos, with periodic time dependence. An asymptotic framework is developed that gives growth rates and frequencies in the highly conducting limit of large magnetic Reynolds number, when modes tend to be ...
0905.0415v1
2009-07-15
Barnett Effect in Thin Magnetic Films and Nanostructures
The Barnett effect refers to the magnetization induced by rotation of a demagnetized ferromagnet. We describe the location and stability of stationary states in rotating nanostructures using the Landau-Lifshitz-Gilbert equation. The conditions for an experimental observation of the Barnett effect in different materials...
0907.2648v1
2009-12-24
Scenarios of Gravitino Dark Matter and their Cosmological and Particle Physics Implications
I report on some scenarios where the gravitino is the dark matter and the supersymmetry breaking mediated by a gauge sector.
0912.4885v1
2010-07-20
Factoring Permutation Matrices Into a Product of Tridiagonal Matrices
Gilbert Strang posited that a permutation matrix of bandwidth $w$ can be written as a product of $N < 2w$ permutation matrices of bandwidth 1. A proof employing a greedy ``parallel bubblesort'' algorithm on the rows of the permutation matrix is detailed and further points of interest are elaborated.
1007.3467v1
2011-05-26
Qu'est-ce qu'une espèce de structures? Genèse et description
This is an overview (in french) of the Theory of Species for a general audience. Basic notions are introduced in a non too technical manner, with an explanation of why should one approach the notion of discrete structures in this particular way.
1105.5406v1
2011-12-16
Reply to the comment of T.Gilbert and D.P.Sanders on "Capturing correlations in chaotic diffusion by approximation methods"
This is a reply to the comment by Gilbert and Sanders [arXiv:1111.6271 (2011)]. We point out that their comment is a follow-up of a previous discussion which we briefly summarize before we refute their new criticism.
1112.3927v1
2012-03-24
A new look at finitely generated metabelian groups
A group is metabelian if its commutator subgroup is abelian. For finitely generated metabelian groups, classical commutative algebra, algebraic geometry and geometric group theory, especially the latter two subjects, can be brought to bear on their study. The object of this paper is to describe some of the new ideas an...
1203.5431v1
2012-06-05
A convergent and precise finite element scheme for Landau-Lifschitz-Gilbert equation
In this paper, we rigorously study an order 2 scheme that was previously proposed by some of the authors. A slight modification is proposed that enables us to prove the convergence of the scheme while simplifying in the same time the inner iteration.
1206.0997v1
2013-01-20
Residual properties of groups defined by basic commutators
In this paper we study the residual nilpotence of groups defined by basic commutators. We prove that the so-called Hydra groups as well as certain of their generalizations and quotients are, in the main, residually torsion-free nilpotent. By way of contrast we give an example of a group defined by two basic commutators...
1301.4629v2
2013-03-21
Anisimov's Theorem for inverse semigroups
The idempotent problem of a finitely generated inverse semigroup is the formal language of all words over the generators representing idempotent elements. This note proves that a finitely generated inverse semigroup with regular idempotent problem is necessarily finite. This answers a question of Gilbert and Noonan Hea...
1303.5239v1
2013-10-13
Underwater Gas Expansion and Deflagration
The underwater combustion of a propane-air mixture in an acrylic cylinder is captured on video from multiple angles. This experiment is designed to provide visual data and pressure time-histories for future CFD validation studies.
1310.3523v1
2014-03-12
A semi-discrete scheme for the stochastic Landau-Lifshitz equation
We propose a new convergent time semi-discrete scheme for the stochastic Landau-Lifshitz-Gilbert equation. The scheme is only linearly implicit and does not require the resolution of a nonlinear problem at each time step. Using a martingale approach, we prove the convergence in law of the scheme up to a subsequence.
1403.3016v1
2014-03-17
Quantum codes from affine variety codes and their subfield-subcodes
We use affine variety codes and their subfield-subcodes for obtaining quantum stabilizer codes via the CSS code construction. With this procedure, we get codes with good parameters and a code whose parameters exceed the CSS quantum Gilbert-Varshamov bound given by Feng and Ma.
1403.4060v2
2015-10-19
Decomposability of Finitely Generated Torsion-free Nilpotent Groups
We describe an algorithm for deciding whether or not a given finitely generated torsion-free nilpotent group is decomposable as the direct product of nontrivial subgroups.
1510.05632v2
2016-02-27
On automatic subsets of the Gaussian integers
Suppose that $a$ and $b$ are multiplicatively independent Gaussian integers, that are both of modulus~$\geq \sqrt 5$. We prove that there exist a $X\subset \mathbb Z[i]$ which is $a$-automatic but not $b$-automatic. This settles a problem of Allouche, Cateland, Gilbert, Peitgen, Shallit, and Skordev.
1602.08579v3
2016-03-02
On self-dual double circulant codes
Self-dual double circulant codes of odd dimension are shown to be dihedral in even characteristic and consta-dihedral in odd characteristic. Exact counting formulae are derived for them and used to show they contain families of codes with relative distance satisfying a modified Gilbert-Varshamov bound.
1603.00762v1
2016-09-22
Manipulation of magnetic Skyrmions with a Scanning Tunneling Microscope
The dynamics of a single magnetic Skyrmion in an atomic spin system under the influence of Scanning Tunneling Microscope is investigated by computer simulations solving the Landau-Lifshitz-Gilbert equation. Two possible scenarios are described: manipulation with aid of a spin-polarized tunneling current and by an elect...
1609.06797v1
2016-11-03
Quantile Reinforcement Learning
In reinforcement learning, the standard criterion to evaluate policies in a state is the expectation of (discounted) sum of rewards. However, this criterion may not always be suitable, we consider an alternative criterion based on the notion of quantiles. In the case of episodic reinforcement learning problems, we prop...
1611.00862v1
2017-01-30
Elementary equivalence vs commensurability for hyperbolic groups
We study to what extent torsion-free (Gromov)-hyperbolic groups are elementarily equivalent to their finite index subgroups. In particular, we prove that a hyperbolic limit group either is a free product of cyclic groups and surface groups, or admits infinitely many subgroups of finite index which are pairwise non elem...
1701.08853v1
2017-08-01
Imaging from the Inside Out: Inverse Scattering with Photoactivated Internal Sources
We propose a method to reconstruct the optical properties of a scattering medium with subwavelength resolution. The method is based on the solution to the inverse scattering problem with photoactivated internal sources. Numerical simulations of three-dimensional structures demonstrate that a resolution of approximately...
1708.00128v1
2017-09-22
On self-dual four circulant codes
Four circulant codes form a special class of $2$-generator, index $4$, quasi-cyclic codes. Under some conditions on their generator matrices they can be shown to be self-dual. Artin primitive root conjecture shows the existence of an infinite subclass of these codes satisfying a modified Gilbert-Varshamov bound.
1709.07548v1
2018-02-21
Enhanced global signal of neutral hydrogen due to excess radiation at cosmic dawn
We revisit the global 21cm signal calculation incorporating a possible radio background at early times, and find that the global 21cm signal shows a much stronger absorption feature, which could enhance detection prospects for future 21 cm experiments. In light of recent reports of a possible low-frequency excess radio...
1802.07432v1
2019-03-22
Nonlinear Iterative Hard Thresholding for Inverse Scattering
We consider the inverse scattering problem for sparse scatterers. An image reconstruction algorithm is proposed that is based on a nonlinear generalization of iterative hard thresholding. The convergence and error of the method was analyzed by means of coherence estimates and compared to numerical simulations.
1903.10875v1
2019-04-06
Phenomenological description of the dynamics of bipartite antiferromagnets in the limit of strong exchange
The equation of motion of the staggered order parameter is derived in a step-by-step manner from the coupled Landau-Lifshitz-Gilbert dynamics of bipartite spin moments in the limit of strong antiferromagnetic exchange coupling.
1904.03529v4
2019-04-19
Variational approximation of functionals defined on $1$-dimensional connected sets in $\mathbb{R}^n$
In this paper we consider the Euclidean Steiner tree problem and, more generally, (single sink) Gilbert--Steiner problems as prototypical examples of variational problems involving 1-dimensional connected sets in $\mathbb{R}^n$. Following the the analysis for the planar case presented in [4], we provide a variational a...
1904.09328v1
2020-03-02
Improved Gilbert-Varshamov Bound for Entanglement-Assisted Asymmetric Quantum Error Correction by Symplectic Orthogonality
We propose and prove an existential theorem for entanglement-assisted asymmetric quantum error correction. Then we demonstrate its superiority over the conventional one.
2003.00668v2
2020-07-14
Competitively Pricing Parking in a Tree
Motivated by demand-responsive parking pricing systems we consider posted-price algorithms for the online metrical matching problem and the online metrical searching problem in a tree metric. Our main result is a poly-log competitive posted-price algorithm for online metrical searching.
2007.07294v2
2021-05-14
Very regular solution to Landau-Lifshitz system with spin-polarized transport
In this paper, we provide a precise description of the compatibility conditions for the initial data so that one can show the existence and uniqueness of regular short-time solution to the Neumann initial-boundary problem of a class of Landau-Lifshitz-Gilbert system with spin-polarized transport, which is a strong nonl...
2105.06616v1
2022-09-23
Limiting Distributions of Sums with Random Spectral Weights
This paper studies the asymptotic properties of weighted sums of the form $Z_n=\sum_{i=1}^n a_i X_i$, in which $X_1, X_2, \ldots, X_n$ are i.i.d.~random variables and $a_1, a_2, \ldots, a_n$ correspond to either eigenvalues or singular values in the classic Erd\H{o}s-R\'enyi-Gilbert model. In particular, we prove centr...
2209.11389v1
2023-09-16
Expansion of the Critical Intensity for the Random Connection Model
We derive an asymptotic expansion for the critical percolation density of the random connection model as the dimension of the encapsulating space tends to infinity. We calculate rigorously the first expansion terms for the Gilbert disk model, the hyper-cubic model, the Gaussian connection kernel, and a coordinate-wise ...
2309.08830v1
2024-03-14
Remarks on the rate of linear vortex symmetrization
We reformulate results from the paper ``Linear vortex symmetrization: The spectral density function" by Ionescu and the author in simplified forms and derive rigorously the bounds given in Bassom and Gilbert (J. Fluid Mech., 1998), which provided interesting insights on the vortex symmetrization phenomenon.
2403.09397v1
2003-10-29
Comparing Chemical Abundances of the Damped Lya Systems and Metal-Poor Stars
I briefly draw comparisons between the fields of damped Lya and metal-poor stellar abundances. In particular, I examine their complementary age-metallicity relations and comparisons between the damped Lya and dwarf galaxy abundance patterns. Regarding the latter, I describe a series of problems concerning associating h...
0310850v1
2006-12-01
Stochastic excitation and damping of solar-type oscillations
A review on acoustic mode damping and excitation in solar-type stars is presented. Current models for linear damping rates are discussed in the light of recent low-degree solar linewidth measurements with emphasis on the frequency-dependence of damping rates of low-order modes. Recent developments in stochastic excitat...
0612024v1
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 re...
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 ...
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 tem...
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 param...
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 c...
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 O...
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 ac...
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 trans...
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 res...
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 dam...
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 thro...
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 stat...
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 driv...
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 t...
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 organi...
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...
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 ov...
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...
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. Co...
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 perturbat...
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 powe...
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...
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 approximat...
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 ...
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 hi...
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...
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 ...
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 c...
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 vacuu...
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 on...
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 ...
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 forc...
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 m...
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 cla...
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 conver...
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...
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 ...
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 dampin...
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 velocit...
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 r...
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 qu...
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 ...
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...
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 characteris...
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...
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...
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 ampli...
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 partic...
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 estimat...
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 ca...
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 ini...
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 gr...
1607.06530v2