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2011-02-02
Harmonic Oscillator in Heat Bath: Exact simulation of time-lapse-recorded data, exact analytical benchmark statistics
The stochastic dynamics of the damped harmonic oscillator in a heat bath is simulated with an algorithm that is exact for time steps of arbitrary size. Exact analytical results are given for correlation functions and power spectra in the form they acquire when computed from experimental time-lapse recordings. Three app...
1102.0524v1
2011-02-04
A symmetry trip from Caldirola to Bateman damped systems
For the Caldirola-Kanai system, describing a quantum damped harmonic oscillator, a couple of constant-of-motion operators generating the Heisenberg algebra can be found. The inclusion of the standard time evolution symmetry in this algebra for damped systems, in a unitary manner, requires a non-trivial extension of thi...
1102.0990v1
2011-03-03
Determination of the pairing state in iron-based superconductors through neutron scattering
We calculate the spin susceptibility in the s_{+-} and s_{++} superconducting states of the iron pnictides using the effective five orbital model and considering the quasiparticle damping. For the experimentally evaluated magnitude of the quasiparticle damping and the superconducting gap, the results at the wave vector...
1103.0586v2
2011-03-03
Transmission of classical and quantum information through a quantum memory channel with damping
We consider the transfer of classical and quantum information through a memory amplitude damping channel. Such a quantum channel is modeled as a damped harmonic oscillator, the interaction between the information carriers - a train of qubits - and the oscillator being of the Jaynes-Cummings kind. We prove that this mem...
1103.0747v2
2011-03-08
Steady states of the parametric rotator and pendulum
We discuss several steady-state rotation and oscillation modes of the planar parametric rotator and pendulum with damping. We consider a general elliptic trajectory of the suspension point for both rotator and pendulum, for the latter at an arbitrary angle with gravity, with linear and circular trajectories as particul...
1103.1413v1
2011-03-18
Time-periodic solitons in a damped-driven nonlinear Schrödinger equation
Time-periodic solitons of the parametrically driven damped nonlinear Schr\"odinger equation are obtained as solutions of the boundary-value problem on a two-dimensional spatiotemporal domain. We follow the transformation of the periodic solitons as the strength of the driver is varied. The resulting bifurcation diagram...
1103.3604v1
2011-03-28
Motion of position-dependent mass as a damping-antidamping process: Application to the Fermi gas and to the Morse potential
The object of this paper is to investigate, classically and quantum mechanically, the relation existing between the position-dependent effective mass and damping-antidamping dynamics. The quantization of the equations of motion is carried out using the geometric interpretation of the motion, and we compare it with the ...
1103.5440v3
2011-04-30
Resonantly Damped Propagating Kink Waves in Longitudinally Stratified Solar Waveguides
It has been shown that resonant absorption is a robust physical mechanism to explain the observed damping of magnetohydrodynamic (MHD) kink waves in the solar atmosphere due to naturally occurring plasma inhomogeneity in the direction transverse to the direction of the magnetic field. Theoretical studies of this dampin...
1105.0067v1
2011-05-05
The effect of twisted magnetic field on the resonant absorption of MHD waves in coronal loops
The standing quasi modes in a cylindrical incompressible flux tube with magnetic twist that undergoes a radial density structuring is considered in ideal magnetohydrodynamics (MHD). The radial structuring is assumed to be a linearly varying density profile. Using the relevant connection formulae, the dispersion relatio...
1105.1120v1
2011-05-05
Interpreting Graph Cuts as a Max-Product Algorithm
The maximum a posteriori (MAP) configuration of binary variable models with submodular graph-structured energy functions can be found efficiently and exactly by graph cuts. Max-product belief propagation (MP) has been shown to be suboptimal on this class of energy functions by a canonical counterexample where MP conver...
1105.1178v1
2011-05-14
Crossovers in the non-Markovian dynamics of two-qubit entanglements
We study the entanglement dynamics of two non-interacting, spatially separated qubits subject to local environment noises. Based on exactly solvable models for non-Markovian amplitude damping and phase damping noises, we are able to analyze the entanglement dynamics of the two qubits for different coupling bandwidths a...
1105.2859v2
2011-06-17
Controlling Excitations Inversion of a Cooper Pair Box Interacting with a Nanomechanical Resonator
We investigate the action of time dependent detunings upon the excitation inversion of a Cooper pair box interacting with a nanomechanical resonator. The method employs the Jaynes-Cummings model with damping, assuming different decay rates of the Cooper pair box and various fixed and t-dependent detunings. It is shown ...
1106.3379v1
2011-06-22
Tunable Magnonic Frequency and Damping in [Co/Pd]8 Multilayers with Variable Co Layer Thickness
We report the experimental observation of collective picosecond magnetization dynamics in [Co/Pd]8 multilayers with perpendicular magnetic anisotropy. The precession frequency shows large and systematic variation from about 5 GHz to about 90 GHz with the decrease in the Co layer thickness from 1.0 nm to 0.22 nm due to ...
1106.4491v1
2011-07-04
An HI column density threshold for cold gas formation in the Galaxy
We report the discovery of a threshold in the HI column density of Galactic gas clouds below which the formation of the cold phase of HI is inhibited. This threshold is at $N_{HI} = 2 \times 10^{20}$ per cm$^{2}$; sightlines with lower HI column densities have high spin temperatures (median $T_s \sim 1800$ K), indicati...
1107.0744v2
2011-07-11
One-dimensional vertical dust strings in a glass box
The oscillation spectrum of a one-dimensional vertical dust string formed inside a glass box on top of the lower electrode in a GEC reference cell was studied. A mechanism for creating a single vertical dust string is described. It is shown that the oscillation amplitudes, resonance frequencies, damping coefficients, a...
1107.2074v1
2011-07-24
Traveling kinks in cubic nonlinear Ginzburg-Landau equations
Nonlinear cubic Euler-Lagrange equations of motion in the traveling variable are usually derived from Ginzburg-Landau free energy functionals frequently encountered in several fields of physics. Many authors considered in the past damped versions of such equations with the damping term added by hand simulating the fric...
1107.4773v4
2011-08-22
On conditions for asymptotic stability of dissipative infinite-dimensional systems with intermittent damping
We study the asymptotic stability of a dissipative evolution in a Hilbert space subject to intermittent damping. We observe that, even if the intermittence satisfies a persistent excitation condition, if the Hilbert space is infinite-dimensional then the system needs not being asymptotically stable (not even in the wea...
1108.4327v2
2011-08-26
Aligned Major Axes in a Planetary System without Tidal Evolution: The 61 Virginis example
Tidal damping of one of the orbits in a planetary system can lead to aligned major-axes (the so-called "fixed-point" condition), but currently aligned major axes do not necessarily imply such a history. An example is the nominal orbital solution for the 61 Virginis system where two orbits librate about alignment, but e...
1108.5369v1
2011-09-09
Optimal linear optical implementation of a single-qubit damping channel
We experimentally demonstrate a single-qubit decohering quantum channel using linear optics. We implement the channel, whose special cases include both the amplitude-damping channel and the bit-flip channel, using a single, static optical setup. Following a recent theoretical result [M. Piani et al., Phys. Rev. A, 84, ...
1109.2070v1
2011-11-20
Detection of picosecond magnetization dynamics of 50 nm magnetic dots down to the single dot regime
We report an all-optical time-domain detection of picosecond magnetization dynamics of arrays of 50 nm Ni80Fe20 (permalloy) dots down to the single nanodot regime. In the single nanodot regime the dynamics reveals one dominant resonant mode corresponding to the edge mode of the 50 nm dot with slightly higher damping th...
1111.4625v1
2011-12-02
An energy-based computational method in the analysis of the transmission of energy in a chain of coupled oscillators
In this paper we study the phenomenon of nonlinear supratransmission in a semi-infinite discrete chain of coupled oscillators described by modified sine-Gordon equations with constant external and internal damping, and subject to harmonic external driving at the end. We develop a consistent and conditionally stable fin...
1112.0581v1
2012-01-09
Universal response of optimal granular damping devices
Granular damping devices constitute an emerging technology for the attenuation of vibrations based on the dissipative nature of particle collisions. We show that the performance of such devices is independent of the material properties of the particles for working conditions where damping is optimal. Even the suppressi...
1201.1866v2
2012-01-09
Radiative energy loss reduction in an absorptive plasma
The influence of the damping of radiation on the radiative energy loss spectrum of a relativistic charge in an infinite, absorptive plasma is studied. We find increasing reduction of the spectrum with increasing damping. Our studies, which represent an Abelian approximation for the colour charge dynamics in the quark-g...
1201.1890v1
2012-01-10
Nonequilibrium Damping of Collective Motion of Homogeneous Cold Fermi Condensates with Feshbach Resonances
Collisionless damping of a condensate of cold Fermi atoms, whose scattering is controlled by a Feshbach resonance, is explored throughout the BCS and BEC regimes when small perturbations on its phase and amplitude modes are turned on to drive the system slightly out of equilibrium. Using a one-loop effective action, we...
1201.2019v1
2012-01-30
Modeling electricity spot prices using mean-reverting multifractal processes
We discuss stochastic modeling of volatility persistence and anti-correlations in electricity spot prices, and for this purpose we present two mean-reverting versions of the multifractal random walk (MRW). In the first model the anti-correlations are modeled in the same way as in an Ornstein-Uhlenbeck process, i.e. via...
1201.6137v1
2012-05-06
Fractional wave equation and damped waves
In this paper, a fractional generalization of the wave equation that describes propagation of damped waves is considered. In contrast to the fractional diffusion-wave equation, the fractional wave equation contains fractional derivatives of the same order $\alpha,\ 1\le \alpha \le 2$ both in space and in time. We show ...
1205.1199v2
2012-05-14
Critical viscoelastic response in jammed solids
We determine the linear viscoelastic response of jammed packings of athermal repulsive viscous spheres, a model for emulsions, wet foams, and soft colloidal suspensions. We numerically measure the complex shear modulus, a fundamental characterization of the response, and demonstrate that low frequency response displays...
1205.2960v1
2012-06-11
Testing the 130 GeV gamma-ray line with high energy resolution detectors
Recently some hints of the existence of $\gamma$-ray line around 130 GeV are reported according to the analysis of Fermi-LAT data. If confirmed it would be the first direct evidence to show the existence of new physics beyond the standard model. Here we suggest that using the forthcoming high energy resolution $\gamma$...
1206.2241v2
2012-06-14
Finite-temperature dynamics of matter-wave dark solitons in linear and periodic potentials: an example of an anti-damped Josephson junction
We study matter-wave dark solitons in atomic Bose-Einstein condensates at finite temperatures, under the effect of linear and periodic potentials. Our model, namely a dissipative Gross-Pitaevskii equation, is treated analytically by means of dark soliton perturbation theory, which results in a Newtonian equation of mot...
1206.2993v1
2012-06-15
Damping of giant dipole resonance in hot rotating nuclei
The phonon damping model (PDM) is extended to include the effect of angular momentum at finite temperature. The model is applied to the study of damping of giant dipole resonance (GDR) in hot and noncollectively rotating spherical nuclei. The numerical results obtained for Mo88 and Sn106 show that the GDR width increas...
1206.3361v1
2012-06-18
Sampled-data design for robust control of a single qubit
This paper presents a sampled-data approach for the robust control of a single qubit (quantum bit). The required robustness is defined using a sliding mode domain and the control law is designed offline and then utilized online with a single qubit having bounded uncertainties. Two classes of uncertainties are considere...
1206.3897v2
2012-06-25
Trap anharmonicity and sloshing mode of a Fermi gas
For a gas trapped in a harmonic potential, the sloshing (or Kohn) mode is undamped and its frequency coincides with the trap frequency, independently of the statistics, interaction and temperature of the gas. However, experimental trap potentials have usually Gaussian shape and anharmonicity effects appear as the tempe...
1206.5688v2
2012-09-06
Radiative energy loss in the absorptive QGP: taming the long formation lengths in coherent emission
In an absorptive plasma, damping of radiation mechanisms can influence the bremsstrahlung formation in case of large radiation formation lengths. We study qualitatively the influence of this effect on the gluon bremsstrahlung spectrum off heavy quarks in the quark-gluon plasma. Independent of the heavy-quark mass, the ...
1209.1149v1
2012-09-17
Power spectra in the eikonal approximation with adiabatic and non-adiabatic modes
We use the so-called eikonal approximation, recently introduced in the context of cosmological perturbation theory, to compute power spectra for multi-component fluids. We demonstrate that, at any given order in standard perturbation theory, multipoint power spectra do not depend on the large-scale adiabatic modes. Mor...
1209.3662v2
2012-09-26
Linear response theory for hydrodynamic and kinetic equations with long-range interactions
We apply the linear response theory to systems with long-range interactions described by hydrodynamic equations such as the Euler, Smoluchowski, and damped Euler equations. We analytically determine the response of the system submitted to a pulse and to a step function. We compare these results with those obtained for ...
1209.5987v1
2012-09-15
Phase mixing of propagating Alfven waves in a stratified atmosphere: Solar spicules
Alfvenic waves are thought to play an important role in coronal heating and solar wind acceleration. Recent observations by Hinode/SOT showed that the spicules mostly exhibit upward propagating high frequency waves. Here we investigate the dissipation of such waves due to phase mixing in stratified environment of solar...
1210.0485v1
2012-10-03
Effect of temperature and velocity on superlubricity
We study the effects of temperature and sliding velocity on superlubricity in numerical simulations of the Frenkel-Kontorova model. We show that resonant excitations of the phonons in an incommensurate sliding body lead to an effective friction and to thermal equilibrium with energy distributed over the internal degree...
1210.1124v1
2012-10-04
Basic microscopic plasma physics unified and simplified by N-body classical mechanics
Debye shielding, collisional transport, Landau damping of Langmuir waves, and spontaneous emission of these waves are introduced, in typical plasma physics textbooks, in different chapters. This paper provides a compact unified introduction to these phenomena without appealing to fluid or kinetic models, but by using N...
1210.1546v2
2012-10-11
Measurement of the damping of nuclear shell effect in the doubly magic $^{208}$Pb region
The damping of the nuclear shell effect with excitation energy has been measured through an analysis of the neutron spectra following the triton transfer in the $^7$Li induced reaction on $^{205}$Tl. The measured neutron spectra demonstrate the expected large shell correction energy for the nuclei in the vicinity of do...
1210.3213v2
2012-10-16
Optimal control of laser plasma instabilities using Spike Trains of Uneven Duration and Delay (STUD pulses) for ICF and IFE
An adaptive method of controlling parametric instabilities in laser produced plasmas is proposed. It involves fast temporal modulation of a laser pulse on the fastest instability's amplification time scale, adapting to changing and unknown plasma conditions. These pulses are comprised of on and off sequences having at ...
1210.4462v1
2012-10-28
Mass Dependence of Instabilities of an Oscillator with Multiplicative and Additive Noise
We study the instabilities of a harmonic oscillator subject to additive and dichotomous multiplicative noise, focussing on the dependance of the instability threshold on the mass. For multiplicative noise in the damping, the instability threshold is crossed as the mass is decreased, as long as the smaller damping is in...
1210.7433v1
2012-10-30
Extending the Concept of Analog Butterworth Filter for Fractional Order Systems
This paper proposes the design of Fractional Order (FO) Butterworth filter in complex w-plane (w=sq; q being any real number) considering the presence of under-damped, hyper-damped, ultra-damped poles. This is the first attempt to design such fractional Butterworth filters in complex w-plane instead of complex s-plane,...
1210.8194v3
2012-11-24
Effects of Quantum Error Correction on Entanglement Sudden Death
We investigate the effects of error correction on non-local quantum coherence as a function of time, extending the study by Sainz and Bj\"ork. We consider error correction of amplitude damping, pure phase damping and combinations of amplitude and phase damping as they affect both fidelity and quantum entanglement. Init...
1211.5654v2
2012-12-04
Polarization dependence of phonon influences in exciton-biexciton quantum dot systems
We report on a strong dependence of the phonon-induced damping of Rabi dynamics in an optically driven exciton-biexciton quantum dot system on the polarization of the exciting pulse. While for a fixed pulse intensity the damping is maximal for linearly polarized excitation, it decreases with increasing ellipticity of t...
1212.0642v1
2012-12-10
Heat-induced damping modification in YIG/Pt hetero-structures
We experimentally demonstrate the manipulation of magnetization relaxation utilizing a temperature difference across the thickness of an yttrium iron garnet/platinum (YIG/Pt) hetero-structure: the damping is either increased or decreased depending on the sign of the temperature gradient. This effect might be explained ...
1212.2073v1
2012-12-13
Surface plasmon polaritons in a semi-bounded degenerate plasma: role of spatial dispersion and collisions
Surface plasmon polaritons (SPPs) in a semi-bounded degenerate plasma (e.g., a metal) are studied using the quasiclassical mean-field kinetic model, taking into account the spatial dispersion of the plasma (due to quantum degeneracy of electrons) and electron-ion (electron-lattice, for metals) collisions. SPP dispersio...
1212.3040v1
2012-12-13
Branching of quasinormal modes for nearly extremal Kerr black holes
We show that nearly extremal Kerr black holes have two distinct sets of quasinormal modes, which we call zero-damping modes (ZDMs) and damped modes (DMs). The ZDMs exist for all harmonic indices $l$ and $m \ge 0$, and their frequencies cluster onto the real axis in the extremal limit. The DMs have nonzero damping for a...
1212.3271v1
2012-12-31
Effects of lateral device size and material properties on the ferromagnetic resonance response of spinwave eigen-modes in magnetic devices
We analyze the effects of lateral device size and magnetic material parameters on the ferromagnetic resonance (FMR) response. Results presented are directly relevant to widely used FMR experimental techniques for extracting magnetic parameters from thin films, the results of which are often assumed to carry over to cor...
1212.6835v1
2013-01-16
Gain-tunable optomechanical cooling in a laser cavity
We study the optical cooling of the resonator mirror in a cavity-optomechanical system that contains an optical gain medium. We find that the optical damping rate is vanishingly small for an incoherently pumped laser above threshold. In the presence of an external coherent drive however, the optical damping rate can be...
1301.3762v2
2013-01-18
Adiabatic stability under semi-strong interactions: The weakly damped regime
We rigorously derive multi-pulse interaction laws for the semi-strong interactions in a family of singularly-perturbed and weakly-damped reaction-diffusion systems in one space dimension. Most significantly, we show the existence of a manifold of quasi-steady N-pulse solutions and identify a "normal-hyperbolicity" cond...
1301.4466v1
2013-01-24
Spin transport parameters in metallic multilayers determined by ferromagnetic resonance measurements of spin pumping
We measured spin transport in nonferromagnetic (NM) metallic multilayers from the contribution to damping due to spin pumping from a ferromagnetic Co90Fe10 thin film. The multilayer stack consisted of NM1/NM2/Co90Fe10(2 nm)/NM2/NM3 with varying NM materials and thicknesses. Using conventional theory for one dimensional...
1301.5861v1
2013-02-11
Low-damping epsilon-near-zero slabs: nonlinear and nonlocal optical properties
We investigate second harmonic generation, low-threshold multistability, all-optical switching, and inherently nonlocal effects due to the free-electron gas pressure in an epsilon-near-zero (ENZ) metamaterial slab made of cylindrical, plasmonic nanoshells illuminated by TM-polarized light. Damping compensation in the E...
1302.2392v1
2013-02-14
A Matlab toolbox for fractional relaxation-oscillation equations
Stress relaxation and oscillation damping of complex viscoelastic media often manifest history- and path-dependent physical behaviors and cannot accurately be described by the classical models. Recent research found that fractional derivative models can characterize such complex relaxation and damping. However, to our ...
1302.3384v1
2013-03-11
The Analysis of Long-Term Frequency and Damping Wandering in Buildings Using the Random Decrement Technique
The characterization and monitoring of buildings is an issue that has attracted the interest of many sectors over the last two decades. With the increasing use of permanent, continuous and real-time networks, ambient vibrations can provide a simple tool for the identification of dynamic building parameters. This study ...
1303.2642v1
2013-03-21
Optimizing atomic resolution of force microscopy in ambient conditions
Ambient operation poses a challenge to AFM because in contrast to operation in vacuum or liquid environments, the cantilever dynamics change dramatically from oscillating in air to oscillating in a hydration layer when probing the sample. We demonstrate atomic resolution by imaging of the KBr(001) surface in ambient co...
1303.5204v2
2013-04-10
Current Sheets and Collisionless Damping in Kinetic Plasma Turbulence
We present the first study of the formation and dissipation of current sheets at electron scales in a wave-driven, weakly collisional, 3D kinetic turbulence simulation. We investigate the relative importance of dissipation associated with collisionless damping via resonant wave-particle interactions versus dissipation ...
1304.2958v2
2013-04-22
Constant residual electrostatic electron plasma mode in Vlasov-Ampere system
In a collisionless Vlasov-Poisson (V-P) electron plasma system, two types of modes for electric field perturbation exist: the exponentially Landau damped electron plasma waves and the initial-value sensitive ballistic modes. Here, the V-P system is modified slightly to a Vlasov-Ampere (V-A) system. A new constant resid...
1304.5883v2
2013-04-23
Existence and non-existence of breather solutions in damped and driven nonlinear lattices
We investigate the existence of spatially localised solutions, in the form of discrete breathers, in general damped and driven nonlinear lattice systems of coupled oscillators. Conditions for the exponential decay of the difference between the maximal and minimal amplitudes of the oscillators are provided which proves ...
1304.6370v3
2013-06-21
Inviscid damping and the asymptotic stability of planar shear flows in the 2D Euler equations
We prove asymptotic stability of shear flows close to the planar Couette flow in the 2D inviscid Euler equations on $\Torus \times \Real$. That is, given an initial perturbation of the Couette flow small in a suitable regularity class, specifically Gevrey space of class smaller than 2, the velocity converges strongly i...
1306.5028v3
2013-07-12
Spin injection from topological insulator tunnel-coupled to metallic leads
We study theoretically helical edge states of 2D and 3D topological insulators (TI) tunnel-coupled to metal leads and show that their transport properties are strongly affected by contacts as the latter play a role of a heat bath and induce damping and relaxation of electrons in the helical states of TI. A simple struc...
1307.3333v1
2013-07-19
Damping and non-linearity of a levitating magnet in rotation above a superconductor
We study the dissipation of moving magnets in levitation above a superconductor. The rotation motion is analyzed using optical tracking techniques. It displays a remarkable regularity together with long damping time up to several hours. The magnetic contribution to the damping is investigated in detail by comparing 14 ...
1307.5155v1
2013-07-19
Perfect squeezing by damping modulation in circuit quantum electrodynamics
Dissipation-driven quantum state engineering uses the environment to steer the state of quantum systems and preserve quantum coherence in the steady state. We show that modulating the damping rate of a microwave resonator generates a vacuum squeezed state of arbitrary squeezing strength, thereby constituting a mechanis...
1307.5311v2
2013-07-27
Charge-carrier-induced frequency renormalization, damping and heating of vibrational modes in nanoscale junctions
In nanoscale junctions the interaction between charge carriers and the local vibrations results in renormalization, damping and heating of the vibrational modes. We here formulate a nonequilibrium Green's functions based theory to describe such effects. Studying a generic junction model with an off-resonant electronic ...
1307.7288v3
2013-07-30
Phase retrapping in a pointlike $\varphi$ Josephson junction: the Butterfly effect
We consider a $\varphi$ Josephson junction, which has a bistable zero-voltage state with the stationary phases $\psi=\pm\varphi$. In the non-zero voltage state the phase "moves" viscously along a tilted periodic double-well potential. When the tilting is reduced quasistatically, the phase is retrapped in one of the pot...
1307.8042v1
2013-08-10
CESR Test Accelerator
The Cornell Electron Storage Ring (CESR) was reconfigured in 2008 as a test accelerator to investigate the physics of ultra-low emittance damping rings. During the approximately 40 days/year available for dedicated operation as a test accelerator, specialized instrumentation is used to measure growth and mitigation of ...
1308.2325v1
2013-09-09
Characterization of the International Linear Collider damping ring optics
A method is presented for characterizing the emittance dilution and dynamic aperture for an arbitrary closed lattice that includes guide field magnet errors, multipole errors and misalignments. This method, developed and tested at the Cornell Electron Storage Ring Test Accelerator (CesrTA), has been applied to the damp...
1309.2248v3
2013-09-19
Van der Waals Coefficients for the Alkali-metal Atoms in the Material Mediums
The damping coefficients for the alkali atoms are determined very accurately by taking into account the optical properties of the atoms and three distinct types of trapping materials such as Au (metal), Si (semi-conductor) and vitreous SiO2 (dielectric). Dynamic dipole polarizabilities are calculated precisely for the ...
1309.4897v1
2013-10-13
What the Timing of Millisecond Pulsars Can Teach us about Their Interior
The cores of compact stars reach the highest densities in nature and therefore could consist of novel phases of matter. We demonstrate via a detailed analysis of pulsar evolution that precise pulsar timing data can constrain the star's composition, through unstable global oscillations (r-modes) whose damping is determi...
1310.3524v2
2013-11-28
Conservative effects in spin-transfer-driven magnetization dynamics
It is shown that under appropriate conditions spin-transfer-driven magnetization dynamics in a single-domain nanomagnet is conservative in nature and admits a specific integral of motion, which is reduced to the usual magnetic energy when the spin current goes to zero. The existence of this conservation law is connecte...
1311.7344v1
2013-12-05
The initial condition problems of damped quantum harmonic oscillator
We investigate the exact dynamics of the damped quantum harmonic oscillator under the (un)correlated initial conditions. The master equation is generalized to the cases of the arbitrary factorized state and/or Gaussian state. We show that the variances of the factorized Gaussian state do not sensitively depend on the i...
1312.1454v1
2013-12-13
Optical variability of quasars: a damped random walk
A damped random walk is a stochastic process, defined by an exponential covariance matrix that behaves as a random walk for short time scales and asymptotically achieves a finite variability amplitude at long time scales. Over the last few years, it has been demonstrated, mostly but not exclusively using SDSS data, tha...
1312.3966v1
2013-12-25
Non-linear damping of visco-resistive Alfven waves in solar spicules
Interaction of Alfven waves with plasma inhomogeneities generates phase mixing which can lead to dissipate Alfven waves and to heat the solar plasma. Here we study the dissipation of Alfven waves by phase mixing due to viscosity and resistivity variations with height. We also consider nonlinear magnetohydrodynamic (MHD...
1312.7866v1
2013-12-31
A novel variability-based method for quasar selection: evidence for a rest frame ~54 day characteristic timescale
We compare quasar selection techniques based on their optical variability using data from the Catalina Real-time Transient Survey (CRTS). We introduce a new technique based on Slepian wavelet variance (SWV) that shows comparable or better performance to structure functions and damped random walk models but with fewer a...
1401.1785v1
2014-02-09
Manipulation of tripartite-to-bipartite entanglement localization under quantum noises and its application to entanglement distribution
This paper is to investigate the effects of quantum noises on entanglement localization by taking an example of reducing a three-qubit Greenberger-Horne-Zeilinger (GHZ) state to a two-qubit entangled state. We consider, respectively, two types of quantum decoherence, i.e., amplitude-damping and depolarizing decoherence...
1402.1914v2
2014-02-25
Thermodynamic anomalies in the presence of dissipation: from the free particle to the harmonic oscillator
A free particle coupled to a heat bath can exhibit a number of thermodynamic anomalies like a negative specific heat or reentrant classicality. These low-temperature phenomena are expected to be modified at very low temperatures where finite-size effects associated with the discreteness of the energy spectrum become re...
1402.6221v1
2014-02-26
Magneto-elastic modes and lifetime of magnons in thin yttrium-iron garnet films
We calculate the effects of the spin-lattice coupling on the magnon spectrum of thin ferromagnetic films consisting of the magnetic insulator yttrium-iron garnet. The magnon-phonon hybridisation generates a characteristic minimum in the spin dynamic structure factor which quantitatively agrees with recent Brillouin lig...
1402.6575v2
2014-02-28
A new way to evaluate x-ray Brillouin scattering data
Making use of the classical second moment sum rule, it is possible to convert a series of constant-Q x-ray Brillouin scattering scans (Q momentum transfer) into a series of constant frequency scans over the measured $Q$ range. The method is applied to literature results for the phonon dispersion in liquid vitreous sili...
1402.7237v1
2014-03-10
Quantum Fisher Information of W States in Decoherence Channels
We study the quantum Fisher information (QFI) of W states analytically with respect to SU(2) rotations in the basic decoherence channels i.e. depolarizing (DPC), amplitude damping (ADC) and phase damping (PDC), and present the interesting behavior of QFI of W states, especially when compared to that of GHZ states [Ma e...
1403.2376v1
2014-03-14
Silk damping at a redshift of a billion: a new limit on small-scale adiabatic perturbations
We study the dissipation of small-scale adiabatic perturbations at early times when the Universe is hotter than T ~ 0.5 keV. When the wavelength falls below the damping scale 1/kD, the acoustic modes diffuse and thermalize, causing entropy production. Before neutrino decoupling, kD is primarily set by the neutrino shea...
1403.3697v1
2014-06-02
CMB $μ$ distortion from primordial gravitational waves
We propose a new mechanism of generating the $\mu$ distortion in cosmic microwave background (CMB) originated from primordial gravitational waves. Such $\mu$ distortion is generated by the damping of the temperature anisotropies through the Thomson scattering, even on scales larger than that of Silk damping. This mecha...
1406.0451v2
2014-06-04
Self-organized escape processes of linear chains in nonlinear potentials
An enhancement of localized nonlinear modes in coupled systems gives rise to a novel type of escape process. We study a spatially one dimensional set-up consisting of a linearly coupled oscillator chain of $N$ mass-points situated in a metastable nonlinear potential. The Hamilton-dynamics exhibits breather solutions as...
1406.0938v1
2014-06-08
Dissipation-driven squeezed and sub-Poissonian mechanical states in quadratic optomechanical systems
In this work we study an optomechanical system in which there is a purely quadratic optomechanical coupling between the optical and mechanical modes. The optical mode is pumped by three coherent fields and the mechanical mode is parametrically driven. We show that if the frequencies and amplitudes of both optical and m...
1406.1987v3
2014-06-13
Frequency-dependent damping in propagating slow magneto-acoustic waves
Propagating slow magneto-acoustic waves are often observed in polar plumes and active region fan loops. The observed periodicities of these waves range from a few minutes to few tens of minutes and their amplitudes were found to decay rapidly as they travel along the supporting structure. Previously, thermal conduction...
1406.3565v1
2014-06-24
On finite density effects on cosmic reheating and moduli decay and implications for Dark Matter production
We study the damping of an oscillating scalar field in a Friedmann-Robertson-Walker spacetime by perturbative processes, taking into account the finite density effects that interactions with the plasma of decay products have on the damping rate. The scalar field may be identified with the inflaton, in which case this p...
1406.6243v2
2014-08-13
Probing dense matter in compact star cores with radio pulsar data
Astrophysical observations of compact stars provide, in addition to collider experiments, the other big source of information on matter under extreme conditions. The largest and most precise data set about neutron stars is the timing data of radio pulsars. We show how this unique data can be used to learn about the ult...
1408.3152v1
2014-08-25
Spin-Scattering Rates in Metallic Thin Films Measured by Ferromagnetic Resonance Damping Enhanced by Spin-Pumping
We determined the spin-transport properties of Pd and Pt thin films by measuring the increase in ferromagnetic resonance damping due to spin-pumping in ferromagnetic (FM)-nonferromagnetic metal (NM) multilayers with varying NM thicknesses. The increase in damping with NM thickness depends strongly on both the spin- and...
1408.5921v2
2014-08-27
Quasi-particle Lifetime in a Mixture of Bose and Fermi Superfluids
In this letter, to reveal the effect of quasi-particle interactions in a Bose-Fermi superfluid mixture, we consider the lifetime of quasi-particle of Bose superfluid due to its interaction with quasi-particles in Fermi superfluid. We find that this damping rate, i.e. inverse of the lifetime, has quite different thresho...
1408.6419v1
2014-09-04
A numerical study of the pull-in instability in some free boundary models for MEMS
In this work we numerically compute the bifurcation curve of stationary solutions for the free boundary problem for MEMS in one space dimension. It has a single turning point, as in the case of the small aspect ratio limit. We also find a threshold for the existence of global-in-time solutions of the evolution equation...
1409.1291v2
2014-09-15
Direct path from microscopic mechanics to Debye shielding, Landau damping, and wave-particle interaction
The derivation of Debye shielding and Landau damping from the $N$-body description of plasmas is performed directly by using Newton's second law for the $N$-body system. This is done in a few steps with elementary calculations using standard tools of calculus, and no probabilistic setting. Unexpectedly, Debye shielding...
1409.4323v1
2014-09-19
Damping of metallized bilayer nanomechanical resonators at room temperature
We investigate the influence of gold thin-films subsequently deposited on a set of initially bare, doubly clamped, high-stress silicon nitride string resonators at room temperature. Analytical expressions for resonance frequency, quality factor and damping for both in- and out-of-plane flexural modes of the bilayer sys...
1409.5670v1
2014-10-09
Non-Fermi-liquid behavior and anomalous suppression of Landau damping in layered metals close to ferromagnetism
We analyse the low-energy physics of nearly ferromagnetic metals in two spatial dimensions using the functional renormalization group technique. We find a new low-energy fixed point, at which the fermionic (electron-like) excitations are non-Fermi-liquid ($z_f = 13/10$) and the magnetic fluctuations exhibit an anomalou...
1410.2539v3
2014-10-09
Special mean motion resonance pairs: Mimas-Tethys and Titan-Hyperion
Five pairs of large solar system satellites occupy first order mean-motion resonances (MMRs). Among these, the pairs of Mimas-Tethys and Titan-Hyperion are special. They are located much deeper in resonance than the others and their critical arguments librate with much greater amplitudes. These characteristics are trac...
1410.2648v1
2014-11-13
Stability and bifurcation for the Kuramoto model
We study the mean-field limit of the Kuramoto model of globally coupled oscillators. By studying the evolution in Fourier space and understanding the domain of dependence, we show a global stability result. Moreover, we can identify function norms to show damping of the order parameter for velocity distributions and pe...
1411.3752v3
2014-11-26
A singular finite element technique for calculating continuum damping of Alfvén eigenmodes
Damping due to continuum resonances can be calculated using dissipation-less ideal magnetohydrodynamics (MHD) provided that the poles due to these resonances are properly treated. We describe a singular finite element technique for calculating the continuum damping of Alfv\'{e}n waves. A Frobenius expansion is used to ...
1411.7111v1
2014-11-26
Energy decay for a locally undamped wave equation
We study the decay rate for the energy of solutions of a damped wave equation in a situation where the Geometric Control Condition is violated. We assume that the set of undamped trajectories is a flat torus of positive codimension and that the metric is locally flat around this set. We further assume that the damping ...
1411.7271v1
2014-12-05
Entanglement Dynamics of Quantum Oscillators Nonlinearly Coupled to Thermal Environments
We study the asymptotic entanglement of two quantum harmonic oscillators nonlinearly coupled to an environment. Coupling to independent baths and a common bath are investigated. Numerical results obtained using the Wangsness-Bloch-Redfield method are supplemented by analytical results in the rotating wave approximation...
1412.1999v1
2014-12-08
The dispersion modification of electrostatic geodesic acoustic mode by electron geodesic drift current
The past studies treated the perturbed distribution of circulating electrons as adiabatic one when studying the dispersion relation of electrostatic geodesic acoustic mode(GAM). In this paper, the flow of electron geodesic current (FEGC) is added to modify this adiabatic distribution. Based on the drift kinetic theory,...
1412.2481v1
2014-12-10
Alfvenic Turbulence Beyond the Ambipolar Diffusion Scale
We investigate the nature of the Alfv\'enic turbulence cascade in two fluid MHD simulations in order to determine if turbulence is damped once the ion and neutral species become decoupled at a critical scale called the ambipolar diffusion scale (L$_{AD}$). Using mode decomposition to separate the three classical MHD mo...
1412.3452v1
2015-01-19
Linear wave action decay entailed by Landau damping in inhomogeneous, nonstationary and anisotropic plasma
This paper addresses the linear propagation of an electron wave in a collisionless, inhomogeneous, nonstationary and anisotropic plasma. The plasma is characterized by its distribution function, $f_H$, at zero order in the wave amplitude. This distribution function, from which are derived all the hydrodynamical quantit...
1501.04485v1
2015-01-23
Response solutions for quasi-periodically forced, dissipative wave equations
We consider several models of nonlinear wave equations subject to very strong damping and quasi-periodic external forcing. This is a singular perturbation, since the damping is not the highest order term. We study the existence of response solutions (i.e., quasi-periodic solutions with the same frequency as the forcing...
1501.05979v1