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2011-12-15
Diffusion-Induced Oscillations of Extended Defects
From a simple model for the driven motion of a planar interface under the influence of a diffusion field we derive a damped nonlinear oscillator equation for the interface position. Inside an unstable regime, where the damping term is negative, we find limit-cycle solutions, describing an oscillatory propagation of the...
1112.3669v1
2012-01-03
Dynamics of DNA Bubble in Viscous Medium
The damping effect to the DNA bubble is investigated within the Peyrard-Bishop model. In the continuum limit, the dynamics of the bubble of DNA is described by the damped nonlinear Schrodinger equation and studied by means of variational method. It is shown that the propagation of solitary wave pattern is not vanishing...
1201.0689v2
2012-01-18
Magnetohydrodynamic Waves in Partially Ionized Prominence Plasmas
Prominences or filaments are cool clouds of partially ionized plasma living in the solar corona. Ground- and space-based observations have confirmed the presence of oscillatory motions in prominences and they have been interpreted in terms of magnetohydrodynamic (MHD) waves. Existing observational evidence points out t...
1201.3752v1
2012-01-30
Volatility-dependent damping of evaporation-driven Bénard-Marangoni instability
The interface between a pure liquid and its vapor is usually close to saturation temperature, hence strongly hindering any thermocapillary flow. In contrast, when the gas phase contains an inert gas such as air, surface-tension-driven convection is easily observed. We here reconcile these two facts by studying the corr...
1201.6334v1
2012-02-18
Dynamics of multi-modes maximum entangled coherent state over amplitude damping channel
The dynamics of maximum entangled coherent state travels through an amplitude damping channel is investigated. For small values of the transmissivity rate the travelling state is very fragile to this noise channel, where it suffers from the phase flip error with high probability. The entanglement decays smoothly for la...
1202.4089v1
2012-03-02
Damping-Antidamping Effect on Comets Motion
We make an observation about Galilean transformation on a 1-D mass variable systems which leads us to the right way to deal with mass variable systems. Then using this observation, we study two-bodies gravitational problem where the mass of one of the bodies varies and suffers a damping-antidamping effect due to star w...
1203.0495v2
2012-03-03
Necessary and sufficient conditions of freezing phenomena of quantum discord under phase damping
We investigate the freezing phenomenon of quantum discord occurring in phase damping noise processes. By relating the expression of the time variation of the discord to the convex function of relative entropy, we obtain the necessary and sufficient conditions of the phenomenon for standard Bell-diagonal states. These c...
1203.0650v3
2012-03-06
Universal anomalous diffusion of weakly damped particles
We show that anomalous diffusion arises in two different models for the motion of randomly forced and weakly damped particles: one is a generalisation of the Ornstein-Uhlenbeck process with a random force which depends on position as well as time, the other is a generalisation of the Chandrasekhar-Rosenbluth model of s...
1203.1354v1
2012-03-09
Collective Light Emission of a Finite Size Atomic Chain
Radiative properties of collective electronic states in a one dimensional atomic chain are investigated. Radiative corrections are included with emphasize put on the effect of the chain size through the dependence on both the number of atoms and the lattice constant. The damping rates of collective states are calculate...
1203.2094v1
2012-03-13
Monopoles in ferromagnetic metals
The aim of this short review is to give an introduction to monopoles and to present theoretical derivation of two particular monopoles in ferromagnetic metals, a hedgehog monopole and a spin damping monopole. Spin damping monopoles can be generated in simple systems such as a junction of a ferromagnet and a heavy eleme...
1203.2709v1
2012-03-16
Report from KEK (High gradient study results from Nextef)
Most up-to-date high gradient test of the CLIC prototype structures as of September 2011 is described in this report. The "T24" undamped structure showed fast processing time, still-decreasing breakdown rate and its breakdown rate was estimated to be as low as the CLIC requirement. The "TD24" damped structure showed no...
1203.3626v1
2012-03-30
Energy decay rates for solutions of the wave equation with linear damping in exterior domain
In this paper we study the behavior of the energy of solutions of the wave equation with localized damping in exterior domain. We assume that the damper is positive at infinity. Under the Geometric Control Condition of Bardos et al (1992), we prove that: 1) The total energy decay like O(1/t) and L^2-norm is bounded for...
1203.6780v4
2012-04-03
Modification in Silling's Peridynamic Formulation of Elasticity Theory for Discontinuities and Long-Range Forces
We suggest modified version of Silling's peridynamic equation of motion within the framework of Silling's peridynamics formulation (J. Mech. Phys. Solids {\bf 48}, pp.175-209, 2000) of elasticity theory. The modified equation contains an additional damping force term. This term can eliminate artificial oscillations in ...
1204.0612v2
2012-04-06
Experimental signatures of the quantum-classical transition in a nanomechanical oscillator modeled as a damped driven double-well problem
We demonstrate robust and reliable signatures for the transition from quantum to classical behavior in the position probability distribution of a damped double-well system using the Qunatum State Diffusion approach to open quantum systems. We argue that these signatures are within experimental reach, for example in a d...
1204.1397v1
2012-05-31
The impact of fill patterns on the fast ion instability in the ILC damping ring
The ions produced via collisional ionization of the residual gas molecules in vacuum pipe with the circulating electron beam have deleterious effect on the beam properties and may become a limiting factor for the machine's performance. For the electron damping ring of the International Linear Collider (ILC), the ion in...
1205.6977v1
2012-06-11
Damping and decoherence of Fock states in a nanomechanical resonator due to two level systems
We numerically investigate the decay of initial quantum Fock states and their superpositions for a mechanical resonator mode coupled to an environment comprising interacting, damped tunneling two level system (TLS) defects. The cases of one, three, and six near resonant, interacting TLS's are considered in turn and it ...
1206.2200v1
2012-07-13
Magnetic relaxation in bilayers of yttrium iron garnet/platinum due to the dynamic coupling at the interface
We show that in ferromagnetic (FM)/normal metal (NM) bilayers the dynamic coupling at the interface transfers an additional magnetic relaxation from the heavily damped motion of the conduction electron spins in the NM layer to the FM spins. While the FM relaxation rates due to two-magnon scattering and spin pumping dec...
1207.3330v1
2012-07-23
Quantum interference induced by initial system-environment correlations
We investigate the quantum interference induced by a relative phase in the correlated initial state of a system which consists in a two-level atom interacting with a damped mode of the radiation field. We show that the initial relative phase has significant effects on both the evolution of the atomic excited-state popu...
1207.5474v1
2012-08-21
Dancing bunches as Van Kampen modes
Van Kampen modes are eigen-modes of Jeans-Vlasov equation. Their spectrum consists of continuous and, possibly, discrete parts. Onset of a discrete van Kampen mode means emergence of a coherent mode without any Landau damping; thus, even a tiny couple-bunch wake is sufficient to drive instability. Longitudinal instabil...
1208.4338v1
2012-08-22
Polynomial stabilization of some dissipative hyperbolic systems
We study the problem of stabilization for the acoustic system with a spatially distributed damping. Imposing various hypotheses on the structural properties of the damping term, we identify either exponential or polynomial decay of solutions with growing time. Expo- nential decay rate is shown by means of a time domain...
1208.4485v1
2012-09-07
Quantum Damped Harmonic Oscillator
In this chapter we treat the quantum damped harmonic oscillator, and study mathematical structure of the model, and construct general solution with any initial condition, and give a quantum counterpart in the case of taking coherent state as an initial condition. This is a simple and good model of Quantum Mechanics w...
1209.1437v1
2012-10-08
Comment on "Thermal fluctuations of magnetic nanoparticles" [arXiv:1209.0298]
We comment on some misleading and biased statements appearing in the manuscript arXiv:1209.0298 ("Thermal fluctuations of magnetic nanoparticles") about the use of the damped Landau-Lifshitz equation and the kinetic Langer theory for the calculation of the relaxation rate of magnetic nanoclusters. We reiterate simple s...
1210.2436v1
2012-10-10
Phonon momentum and damping of mechanical resonators
The concept of physical momentum associated to phonons in a crystal, complemented with some fundamental reasoning, implies measurable effects in crystals even at a macroscopic scale. We show that, in close analogy with the transfer of momentum in the kinetic theory of gases, physical momentum carried by of phonons coup...
1210.2847v1
2012-10-12
HTS wiggler concept for a damping ring
Magnetic design proposed for a damping ring (DR) is based on second generation HTS cabling technology applied to the DC windings with a yoke and mu-metal-shimmed pole to achieve ~2T high-quality field within a 86 mm gap and 32-40 cm period. Low levels of current densities (~90-100A/mm2) provide a robust, reliable opera...
1210.3648v1
2012-10-23
Dynamic response of open cell dry foams
We study the mechanical response of an open cell dry foam subjected to periodic forcing using experiments and theory. Using the measurements of the static and dynamic stress-strain relationship, we derive an over-damped model of the foam, as a set of infinitesimal non-linear springs, where the damping term depends on t...
1210.6229v1
2012-10-31
Quantum discord of Bell cat-states under amplitude damping
The evolution of pairwise quantum correlations of Bell cat-states under amplitude damping is examined using the concept of quantum discord which goes beyond entanglement. A closed expression of the quantum discord is explicitly derived. We used of the Koashi-Winter relation. A relation which facilitates the optimizatio...
1210.8309v1
2012-10-31
Upsilon suppression in PbPb collisions at the LHC
We suggest that the combined effect of screening, gluon-induced dissociation, collisional damping, and reduced feed-down explains most of the sequential suppression of Upsilon(nS) states that has been observed in PbPb relative to pp collisions at sqrt(s_NN) = 2.76 TeV. The suppression is thus a clear, albeit indirect, ...
1210.8366v2
2012-11-04
The Threshold between Effective and Noneffective Damping for Semilinear Waves
In this paper we study the global existence of small data solutions to the Cauchy problem for the semilinear wave equation with scale-invariant damping. We obtain estimates for the solution and its energy with the same decay rate of the linear problem. We extend our results to a model with polynomial speed of propagati...
1211.0731v2
2012-11-10
Heavy quark quenching from RHIC to LHC and the consequences of gluon damping
In this contribution to the Quark Matter 2012 conference, we study whether energy loss models established for RHIC energies to describe the quenching of heavy quarks can be applied at LHC with the same success. We also benefit from the larger $p_T$-range accessible at this accelerator to test the impact of gluon dampin...
1211.2281v1
2012-11-30
Local feedback stabilisation to a non-stationary solution for a damped non-linear wave equation
We study a damped semi-linear wave equation in a bounded domain with smooth boundary. It is proved that any sufficiently smooth solution can be stabilised locally by a finite-dimensional feedback control supported by a given open subset satisfying a geometric condition. The proof is based on an investigation of the lin...
1211.7202v1
2012-12-06
The physics of business cycles and inflation
We analyse four consecutive cycles observed in the USA for employment and inflation. They are driven by three oil price shocks and an intended interest rate shock. Non-linear coupling between the rate equations for consumer products as prey and consumers as predators provides the required instability, but its natural d...
1212.1282v1
2012-12-13
CMB Distortions from Damping of Acoustic Waves Produced by Cosmic Strings
We study diffusion damping of acoustic waves in the photon-baryon fluid due to cosmic strings, and calculate the induced $\mu$- and $y$-type spectral distortions of the cosmic microwave background. For cosmic strings with tension within current bounds, their contribution to the spectral distortions is subdominant compa...
1212.3283v2
2013-01-21
Asymptotic parabolicity for strongly damped wave equations
For $S$ a positive selfadjoint operator on a Hilbert space, \[ \frac{d^2u}{dt}(t) + 2 F(S)\frac{du}{dt}(t) + S^2u(t)=0 \] describes a class of wave equations with strong friction or damping if $F$ is a positive Borel function. Under suitable hypotheses, it is shown that \[ u(t)=v(t)+ w(t) \] where $v$ satisfies \[ 2F(S...
1301.4979v1
2013-02-04
Gravity waves on the surface of topological superfluid 3He-B
We have observed waves on the free surface of 3He-B sample at temperatures below 0.2mK. The waves are excited by vibrations of the cryostat and detected by coupling the surface to the Bose-Einstein condensate of magnon quasiparticles in the superfluid. The two lowest gravity-wave modes in our cylindrical container are ...
1302.0764v1
2013-02-12
On the fractional damped oscillators and fractional forced oscillators
In this paper, we use the fractional calculus to discuss the fractional mechanics, where the time derivative is replaced with the fractional derivative of order $\nu$. We deal with the motion of a body in a resisting medium where the retarding force is assumed to be proportional to the fractional velocity which is obta...
1302.2847v1
2013-02-25
Optimal damping algorithm for unrestricted Hartree-Fock calculations
We have developed a couple of optimal damping algorithms (ODAs) for unrestricted Hartree-Fock (UHF) calculations of open-shell molecular systems. A series of equations were derived for both concurrent and alternate constructions of alpha- and beta-Fock matrices in the integral-direct self-consistent-field (SCF) procedu...
1302.6099v1
2013-03-08
Entanglement of Open Quantum Systems in Noninertial Frames
We study the effects of decoherence on the entanglement generated by Unruh effect in accelerated frames by using various combinations of an amplitude damping channel, a phase damping channel and a depolarizing channel in the form of multilocal and collective environments. Using concurrence as entanglement quantifier, w...
1303.2034v1
2013-03-21
Glued trees algorithm under phase damping
We study the behaviour of the glued trees algorithm described by Childs et al. in [STOC `03, Proc. 35th ACM Symposium on Theory of Computing (2004) 59] under decoherence. We consider a discrete time reformulation of the continuous time quantum walk protocol and apply a phase damping channel to the coin state, investiga...
1303.5319v2
2013-04-04
Pais-Uhlenbeck Oscillator with a Benign Friction Force
It is shown that the Pais-Uhlenbeck oscillator with damping, considered by Nesterenko, is a special case of a more general oscillator that has not only a first order, but also a third order friction term. If the corresponding damping constants, \alpha\ and \beta, are both positive and below certain critical values, the...
1304.1325v2
2013-05-13
Guaranteed convergence of the Kohn-Sham equations
A sufficiently damped iteration of the Kohn-Sham equations with the exact functional is proven to always converge to the true ground-state density, regardless of the initial density or the strength of electron correlation, for finite Coulomb systems. We numerically implement the exact functional for one-dimensional con...
1305.2967v2
2013-06-25
Decoherence effects in the quantum qubit flip game using Markovian approximation
We are considering a quantum version of the penny flip game, whose implementation is influenced by the environment that causes decoherence of the system. In order to model the decoherence we assume Markovian approximation of open quantum system dynamics. We focus our attention on the phase damping, amplitude damping an...
1306.5957v1
2013-07-06
The 3-dimensional oscillon equation
On a bounded three-dimensional smooth domain, we consider the generalized oscillon equation with Dirichlet boundary conditions, with time-dependent damping and time-dependent squared speed of propagation. Under structural assumptions on the damping and the speed of propagation, which include the relevant physical case ...
1307.1777v1
2013-08-30
A conservative, skew-symmetric Finite Difference Scheme for the compressible Navier--Stokes Equations
We present a fully conservative, skew-symmetric finite difference scheme on transformed grids. The skew-symmetry preserves the kinetic energy by first principles, simultaneously avoiding a central instability mechanism and numerical damping. In contrast to other skew-symmetric schemes no special averaging procedures ar...
1308.6672v1
2013-09-09
Classical and quantum capacities of a fully correlated amplitude damping channel
We study information transmission over a fully correlated amplitude damping channel acting on two qubits. We derive the single-shot classical channel capacity and show that entanglement is needed to achieve the channel best performance. We discuss the degradability properties of the channel and evaluate the quantum cap...
1309.2219v3
2013-09-13
Polarization hydrodynamics in a one-dimensional polariton condensate
We study the hydrodynamics of a nonresonantly-pumped polariton condensate in a quasi-one-dimensional quantum wire taking into account the spin degree of freedom. We clarify the relevance of the Landau criterion for superfluidity in this dissipative two-component system. Two Cherenkov-like critical velocities are identi...
1309.3494v1
2013-09-26
Imperfect geometric control and overdamping for the damped wave equation
We consider the damped wave equation on a manifold with imperfect geometric control. We show the sub-exponential energy decay estimate in \cite{Chr-NC-erratum} is optimal in the case of one hyperbolic periodic geodesic. We show if the equation is overdamped, then the energy decays exponentially. Finally we show if the ...
1309.6967v1
2013-10-01
Scalar filed evolution and area spectrum for Lovelock-AdS black holes
We study the modes of evolution of massless scalar fields in the asymptotically AdS spacetime surrounding maximally symmetric black holes of large and intermediate size in the Lovelock model. It is observed that all modes are purely damped at higher orders. Also, the rate of damping is seen to be independent of order a...
1310.0159v2
2013-10-16
Perturbative quantum damping of cosmological expansion
Perturbative quantum gravity in the framework of the Schwinger-Keldysh formalism is applied to compute lowest-order corrections to the actual expansion of the Universe described in terms of the spatially flat Friedman-Lematre-Robertson-Walker solution. The classical metric is approximated by a third order polynomial pe...
1310.4308v2
2013-10-27
Loss of non-Gaussianity for damped photon-subtracted thermal states
We investigate non-Gaussianity properties for a set of classical one-mode states obtained by subtracting photons from a thermal state. Three distance-type degrees of non-Gaussianity used for these states are shown to have a monotonic behaviour with respect to their mean photon number. Decaying of their non-Gaussianity ...
1310.7229v1
2013-10-27
Landau damping effects and evolutions of energy spread in small isochronous ring
This paper presents the Landau damping effects on the microwave instability of a coasting long bunch in an isochronous ring due to finite energy spread and emittance. Our two-dimensional (2D) dispersion relation gives more accurate predictions of the microwave instability growth rates of short-wavelength perturbations ...
1310.7253v3
2013-10-28
Robustness of multiparticle entanglement: specific entanglement classes and random states
We investigate the robustness of genuine multiparticle entanglement under decoherence. We consider different kinds of entangled three- and four-qubit states as well as random pure states. For amplitude damping noise, we find that the W-type states are most robust, while other states are not more robust than generic sta...
1310.7336v2
2013-11-22
Complexity of the minimum-time damping of a physical pendulum
We study the minimum-time damping of a physical pendulum by means of a bounded control. In the similar problem for a linear oscillator each optimal trajectory possesses a finite number of control switchings from the maximal to the minimal value. If one considers simultaneously all optimal trajectories with any initial ...
1311.5729v1
2013-12-16
Local Energy Decay for the Damped Wave Equation
We prove local energy decay for the damped wave equation on R^d. The problem which we consider is given by a long range metric perturbation of the Euclidean Laplacian with a short range absorption index. Under a geometric control assumption on the dissipation we obtain an almost optimal polynomial decay for the energy ...
1312.4483v1
2013-12-23
Photonic tuning of quasi-particle decay in a superfluid
We show that the damping rate of elementary excitations of hybrid systems close to a phase transition can undergo a remarkable resonance like enhancement before mode softening takes place. In particular, we consider the friction of a collective density wave in a homogeneous superfluid of weakly interacting bosonic atom...
1312.6719v1
2014-01-04
Entanglement and quantum teleportation via decohered tripartite entangled states
The entanglement behavior of two classes of multi-qubit system, GHZ and GHZ like states passing through a generalized amplitude damping channel is discussed. Despite this channel causes degradation of the entangled properties and consequently their abilities to perform quantum teleportation, one can always improve the ...
1401.0796v1
2014-02-11
New approach for Damping in a squeezed bath and its time evolution through Complete Class of Gaussian Quasi-distributions
By virtue of the thermal entangled states representation of density operator and using dissipative interaction picture we solve the master equation of a driven damped harmonic oscillator in a squeezed bath. We show that the essential part of the dynamics can be expressed by the convolution of initial Wigner function wi...
1402.2545v1
2014-02-11
New approach for solving master equations of density operator for the Jaynes Cummings Model with Cavity Damping
By introducing thermal entangled state representation which can map master equations of density operator in quantum statistics as state vector evolution equations and using dissipative interaction picture we solve the master equation of J-C model with cavity damping. In addition we derive the Wigner function for densit...
1402.2556v1
2014-02-19
Superfluid Bloch dynamics in an incommensurate lattice
We investigate the interplay of disorder and interactions in the accelerated transport of a Bose-Einstein condensate through an incommensurate optical lattice. We show that interactions can effectively cancel the damping of Bloch oscillations due to the disordered potential and we provide a simple model to qualitativel...
1402.4830v1
2014-02-21
Weakly damped acoustic plasmon mode in transition metal dichalcogenides with Zeeman splitting
We analyze the effect of a strong Zeeman field on the spectrum of collective excitations of monolayer transition metal dichalcogenides. The combination of the Dresselhaus type spin orbit coupling and an external Zeeman field result in the lifting of the valley degeneracy in the valence band of these crystals. We show t...
1402.5274v1
2014-04-18
On the Instability and Critical Damping Conditions, $kτ= 1/e$ and $kτ= π/2$ of the equation $\dotθ = -k θ(t-τ)$
In this note, I show that it is possible to use elementary mathematics, instead of the machinery of Lambert function, Laplace Transform, or numerics, to derive the instability condition, $k \tau = \pi/2$, and the critical damping condition, $k\tau = 1/e$, for the time-delayed equation $\dot{\theta} = -k \theta(t-\tau)$...
1404.4763v1
2014-04-22
Nonlinear-damped Duffing oscillators having finite time dynamics
A class of modified Duffing oscillator differential equations, having nonlinear damping forces, are shown to have finite time dynamics, i.e., the solutions oscillate with only a finite number of cycles, and, thereafter, the motion is zero. The relevance of this feature is briefly discussed in relationship to the mathem...
1404.5596v1
2014-05-01
On the collapse of trial solutions for a damped-driven non-linear Schrödinger equation
We consider the focusing 2D non-linear Schr\"odinger equation, perturbed by a damping term, and driven by multiplicative noise. We show that a physically motivated trial solution does not collapse for any admissible initial condition although the exponent of the non-linearity is critical. Our method is based on the con...
1405.0151v3
2014-05-02
Dynamic phase diagram of dc-pumped magnon condensates
We study the effects of nonlinear dynamics and damping by phonons on a system of interacting electronically pumped magnons in a ferromagnet. The nonlinear effects are crucial for constructing the dynamic phase diagram, which describes how "swasing" and Bose-Einstein condensation emerge out of the quasiequilibrated ther...
1405.0522v1
2014-05-05
Finite time extinction for nonlinear Schrodinger equation in 1D and 2D
We consider a nonlinear Schrodinger equation with power nonlinearity, either on a compact manifold without boundary, or on the whole space in the presence of harmonic confinement, in space dimension one and two. Up to introducing an extra superlinear damping to prevent finite time blow up, we show that the presence of ...
1405.0995v1
2014-05-16
Investigation of Power-Law Damping/Dissipative Forces
The properties of a one space-dimension, one particle dynamical system under the influence of a purely dissipative force are investigated. Assuming this force depends only on the velocity, it is demonstrated, in contrast to the case of linear damping, that there exist dissipative forces for which the particle \textquot...
1405.4062v1
2014-06-02
Nonlinear coupler operating on Werner-like states - entanglement creation, its enhancement and preservation
We discuss a model of two nonlinear Kerr-like oscillators, mutually coupled and excited by parametric process. We show that the system's evolution, starting from Werner-like states, remains closed within a small set of two-mode n-photon states the system, and pure two-qubit entangled state can be generated. For some in...
1406.0414v1
2014-06-10
A determining form for the damped driven Nonlinear Schrödinger Equation- Fourier modes case
In this paper we show that the global attractor of the 1D damped, driven, nonlinear Schr\"odinger equation (NLS) is embedded in the long-time dynamics of a determining form. The determining form is an ordinary differential equation in a space of trajectories $X=C_b^1(\mathbb{R}, P_mH^2)$ where $P_m$ is the $L^2$-projec...
1406.2626v1
2014-08-20
Initial Layer and Relaxation Limit of Non-Isentropic Compressible Euler Equations with Damping
In this paper, we study the relaxation limit of the relaxing Cauchy problem for non-isentropic compressible Euler equations with damping in multi-dimensions. We prove that the velocity of the relaxing equations converges weakly to that of the relaxed equations, while other variables of the relaxing equations converges ...
1408.4784v1
2014-08-26
Exponential decay for the damped wave equation in unbounded domains
We study the decay of the semigroup generated by the damped wave equation in an unbounded domain. We first prove under the natural geometric control condition the exponential decay of the semigroup. Then we prove under a weaker condition the logarithmic decay of the solutions (assuming that the initial data are smoothe...
1408.6054v2
2014-10-03
Relaxation of regularity for the Westervelt equation by nonlinear damping with application in acoustic-acoustic and elastic-acoustic coupling
In this paper we show local (and partially global) in time existence for the Westervelt equation with several versions of nonlinear damping. This enables us to prove well-posedness with spatially varying $L_\infty$-coefficients, which includes the situation of interface coupling between linear and nonlinear acoustics a...
1410.0797v1
2014-10-13
Vortex gyration mediated by spin waves driven by an out-of-plane oscillating magnetic field
In this letter we address the vortex core dynamics involved in gyration excitation and damping change by out-of-plane oscillating magnetic fields. When the vortex core is at rest under the effect of in-plane bias magnetic fields, the spin waves excited by the perpendicular magnetic field can induce obvious vortex gyrat...
1410.3230v1
2014-10-23
Non-equilibrium thermodynamics approach to open quantum systems
Open quantum systems are studied from the thermodynamical point of view unifying the principle of maximum informational entropy and the hypothesis of relaxation times hierarchy. The result of the unification is a non-Markovian and local in time master equation that provides a direct connection of dynamical and thermody...
1410.6312v2
2014-10-27
Linear Inviscid Damping for Monotone Shear Flows
In this article, we prove linear stability, scattering and inviscid damping with optimal decay rates for the linearized 2D Euler equations around a large class of strictly monotone shear flows, $(U(y),0)$, in a periodic channel under Sobolev perturbations. Here, we consider the settings of both an infinite periodic cha...
1410.7341v2
2014-11-08
Damping of liquid sloshing by foams: from everyday observations to liquid transport
We perform experiments on the sloshing dynamics of liquids in a rectangular container submitted to an impulse. We show that when foam is placed on top of the liquid the oscillations of the free interface are significantly damped. The ability to reduce sloshing and associated splashing could find applications in numerou...
1411.2123v1
2014-11-17
A geometric mesh smoothing algorithm related to damped oscillations
We introduce a smoothing algorithm for triangle, quadrilateral, tetrahedral and hexahedral meshes whose centerpiece is a simple geometric triangle transformation. The first part focuses on the mathematical properties of the element transformation. In particular, the transformation gives rise directly to a continuous mo...
1411.4390v3
2014-12-05
Exponential dephasing of oscillators in the Kinetic Kuramoto Model
We study the kinetic Kuramoto model for coupled oscillators with coupling constant below the synchronization threshold. We manage to prove that, for any analytic initial datum, if the interaction is small enough, the order parameter of the model vanishes exponentially fast, and the solution is asymptotically described ...
1412.1923v1
2014-12-23
Selftrapping triggered by losses in cavity QED
In a coupled cavity QED network model, we study the transition from a localized super fluid like state to a delocalized Mott insulator like state, triggered by losses. Without cavity losses, the transition never takes place. Further, if one measures the quantum correlations between the polaritons via the negativity, we...
1412.7495v1
2015-01-07
Two-photon lasing by a superconducting qubit
We study the response of a magnetic-field-driven superconducting qubit strongly coupled to a superconducting coplanar waveguide resonator. We observed a strong amplification/damping of a probing signal at different resonance points corresponding to a one and two-photon emission/absorption. The sign of the detuning betw...
1501.01543v1
2015-02-02
Enhanced oscillation lifetime of a Bose-Einstein condensate in the 3D/1D crossover
We have measured the damped motion of a trapped Bose-Einstein condensate, oscillating with respect to a thermal cloud. The cigar-shaped trapping potential provides enough transverse confinement that the dynamics of the system are intermediate between three-dimensional and one-dimensional. We find that oscillations pers...
1502.00430v2
2015-02-03
Nonequilibrium dynamics of an ultracold dipolar gas
We study the relaxation and damping dynamics of an ultracold, but not quantum degenerate, gas consisting of dipolar particles. These simulations are performed using a direct simulation Monte Carlo method and employing the highly anisotropic differential cross section of dipoles in the Wigner threshold regime. We find t...
1502.00960v1
2015-02-01
On the Stability of Cylindrical Tangential Discontinuity, Generation and Damping of Helical Waves
Stability of cylindrical interface between two ideal incompressible fluids, including the magnetic field, surface tension and gravitational field is studied in linear approximation. We found that helical waves arising both in plasma comet tails and on the vertical cylindrical water jet in the air are described by the s...
1502.00989v1
2015-03-04
On the Lewis-Riesenfeld (Dodonov-Man'ko) invariant method
We revise the Lewis-Riesenfeld invariant method for solving the quantum time-dependent harmonic oscillator in light of the Quantum Arnold Transformation previously introduced and its recent generalization to the Quantum Arnold-Ermakov-Pinney Transformation. We prove that both methods are equivalent and show the advanta...
1503.01371v1
2015-03-06
On the strongly damped wave equation with constraint
A weak formulation for the so-called "semilinear strongly damped wave equation with constraint" is introduced and a corresponding notion of solution is defined. The main idea in this approach consists in the use of duality techniques in Sobolev-Bochner spaces, aimed at providing a suitable "relaxation" of the constrain...
1503.01911v1
2015-03-23
Spin-Orbit Torques in Two-Dimensional Rashba Ferromagnets
Magnetization dynamics in single-domain ferromagnets can be triggered by charge current if spin-orbit coupling is sufficiently strong. We apply functional Keldysh theory to investigate Rashba spin-orbit torques in metallic two-dimensional ferromagnets. A reactive, anti-damping-like spin-orbit torque as well as a dissip...
1503.06872v2
2015-04-18
Global Dirichlet Heat Kernel Estimates for Symmetric Lévy Processes in Half-space
In this paper, we derive explicit sharp two-sided estimates for the Dirichlet heat kernels of a large class of symmetric (but not necessarily rotationally symmetric) L\'evy processes on half spaces for all $t>0$. These L\'evy processes may or may not have Gaussian component. When L\'evy density is comparable to a decre...
1504.04673v2
2015-05-05
The transition from the classical to the quantum regime in nonlinear Landau damping
Starting from the Wigner-Moyal equation coupled to Poisson's equation, a simplified set of equations describing nonlinear Landau damping of Langmuir waves is derived. This system is studied numerically, with a particular focus on the transition from the classical to the quantum regime. In the quantum regime several new...
1505.01381v1
2015-05-08
The amplification of weak measurements under quantum noise
The influence of outside quantum noises on the amplification of weak measurements is investigated. Three typical quantum noises are discussed. The maximum values of the pointer's shifts decrease sharply with the strength of the depolarizing channel and phase damping. In order to obtain significant amplified signals, th...
1505.01911v1
2015-05-27
Local energy decay and smoothing effect for the damped Schr{ö}dinger equation
We prove the local energy decay and the smoothing effect for the damped Schr{\"o}dinger equation on R^d. The self-adjoint part is a Laplacian associated to a long-range perturbation of the flat metric. The proofs are based on uniform resolvent estimates obtained by the dissipative Mourre method. All the results depend ...
1505.07200v1
2015-06-01
Local decay for the damped wave equation in the energy space
We improve a previous result about the local energy decay for the damped wave equation on R^d. The problem is governed by a Laplacian associated with a long range perturbation of the flat metric and a short range absorption index. Our purpose is to recover the decay O(t^{--d+$\epsilon$}) in the weighted energy spaces. ...
1506.00377v1
2015-06-03
Giant Phonon Anomaly associated with Superconducting Fluctuations in the Pseudogap Phase of Cuprates
The opening of the pseudogap in underdoped cuprates breaks up the Fermi surface, which may lead to a breakup of the d-wave order parameter into two subband amplitudes and a low energy Leggett mode due to phase fluctuations between them. This causes a large increase in the temperature range of superconducting fluctuatio...
1506.01258v1
2015-06-06
On higher regularity for the Westervelt equation with strong nonlinear damping
We show higher interior regularity for the Westervelt equation with strong nonlinear damping term of the $q$-Laplace type. Secondly, we investigate an interface coupling problem for these models, which arise, e.g., in the context of medical applications of high intensity focused ultrasound in the treatment of kidney st...
1506.02125v1
2015-06-08
Intermode-coupling modulation in the fermion-boson model: heating effects in the BCS regime
Heating induced by an oscillating modulation of the interaction strength in an atomic Fermion pair condensate is analyzed. The coupled fermion-boson model, generalized by incorporating a time-dependent intermode coupling through a magnetic Feshbach resonance, is applied. The dynamics is analytically characterized in a ...
1506.02612v1
2015-06-22
N-body description of Debye shielding and Landau damping
This paper brings further insight into the recently published N-body description of Debye shielding and Landau damping [Escande D F, Elskens Y and Doveil F 2014 Plasma Phys. Control. Fusion 57 025017]. Its fundamental equation for the electrostatic potential is derived in a simpler and more rigorous way. Various physic...
1506.06468v2
2015-07-23
Millisecond newly born pulsars as efficient accelerators of electrons
The newly born millisecond pulsars are investigated as possible energy sources for creating ultra-high energy electrons. The transfer of energy from the star rotation to high energy electrons takes place through the Landau damping of centrifugally driven (via a two stream instability) electrostatic Langmuir waves. Gene...
1507.06415v1
2015-07-28
Stability of solutions to nonlinear wave equations with switching time-delay
In this paper we study well-posedness and asymptotic stability for a class of nonlinear second-order evolution equations with intermittent delay damping. More precisely, a delay feedback and an undelayed one act alternately in time. We show that, under suitable conditions on the feedback operators, asymptotic stability...
1507.07787v1
2015-08-10
Theory of the strongly-damped quantum harmonic oscillator
We analyse the properties of a strongly-damped quantum harmonic oscillator by means of an exact diagonalisation of the full Hamiltonian, including both the oscillator and the reservoir degrees of freedom to which it is coupled. Many of the properties of the oscillator, including its steady-state properties and entangle...
1508.02442v1
2015-08-20
Bump-on-tail instability of twisted excitations in rotating cold atomic clouds
We develop a kinetic theory for twisted density waves (phonons), carrying a finite amount of orbital angular momentum, in large magneto optical traps, where the collective processes due to the exchange of scattered photons are considered. Explicit expressions for the dispersion relation and for the kinetic (Landau) dam...
1508.05127v1
2015-09-30
Approximation of Invariant Measure for Damped Stochastic Nonlinear Schrödinger Equation via an Ergodic Numerical Scheme
In order to inherit numerically the ergodicity of the damped stochastic nonlinear Schr\"odinger equation with additive noise, we propose a fully discrete scheme, whose spatial direction is based on spectral Galerkin method and temporal direction is based on a modification of the implicit Euler scheme. We not only prove...
1509.09148v2
2015-10-02
Cavity and HOM Coupler Design for CEPC
In this paper we will show a cavity and higher order mode (HOM) coupler designing scheme for the Circular Electron-Positron Collider (CEPC) main ring. The cavity radio frequency (RF) design parameters are showed in this paper. The HOM power is calculated based on the beam parameters in the Preliminary Conceptual Design...
1510.00467v1
2015-11-08
Upper semicontinuity of pullback attractors for damped wave equations
In this paper, we study the upper semicontinuity of pullback attractors for a strongly damped wave equation. In particular, under some proper assumptions, we prove that, the pullback attractor $\{A_\varepsilon(t)\}_{t\in\mathbb R}$} of Eq.(1.1) with $\varepsilon\in[0,1]$ satisfies that for any $[a,b]\subset\mathbb R$ a...
1511.02481v2