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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
2013-04-23
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
2013-08-02
Spin pumping damping and magnetic proximity effect in Pd and Pt spin-sink layers
We investigated the spin pumping damping contributed by paramagnetic layers (Pd, Pt) in both direct and indirect contact with ferromagnetic Ni$_{81}$Fe$_{19}$ films. We find a nearly linear dependence of the interface-related Gilbert damping enhancement $\Delta\alpha$ on the heavy-metal spin-sink layer thicknesses t$_\...
1308.0450v2
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
2014-03-10
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
Interface enhancement of Gilbert damping from first-principles
The enhancement of Gilbert damping observed for Ni80Fe20 (Py) films in contact with the non-magnetic metals Cu, Pd, Ta and Pt, is quantitatively reproduced using first-principles scattering theory. The "spin-pumping" theory that qualitatively explains its dependence on the Py thickness is generalized to include a numbe...
1406.6225v2
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
2014-09-04
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
Calculating linear response functions for finite temperatures on the basis of the alloy analogy model
A scheme is presented that is based on the alloy analogy model and allows to account for thermal lattice vibrations as well as spin fluctuations when calculating response quantities in solids. Various models to deal with spin fluctuations are discussed concerning their impact on the resulting temperature dependent magn...
1412.1988v1
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
2015-01-30
A large-scale magnetic shield with 10^6 damping at mHz frequencies
We present a magnetically shielded environment with a damping factor larger than one million at the mHz frequency regime and an extremely low field and gradient over an extended volume. This extraordinary shielding performance represents an improvement of the state of the art in damping the difficult regime of very low...
1501.07861v4
2015-02-01
A Study on the Impact of Wind Generation on the Stability of Electromechanical Oscillations
Wind is becoming an increasingly significant source of energy in modern power generation. Amongst existing technologies, Variable Speed Wind Turbines (VSWT) equipped with Double Fed Induction Generators (DFIG) is widely deployed. Consequently, power systems are now experiencing newer power flow patterns and operating c...
1502.00215v1
2015-02-16
Biomimetic Staggered Composites with Highly Enhanced Energy Dissipation: Design, Modeling, and Test
We investigate the damping enhancement in a class of biomimetic staggered composites via a combination of design, modeling, and experiment. In total, three kinds of staggered composites are designed by mimicking the structure of bone and nacre. These composite designs are realized by 3D printing a rigid plastic and a v...
1502.04568v1
2015-03-02
DAMPE silicon tracker on-board data compression algorithm
The Dark Matter Particle Explorer (DAMPE) is an upcoming scientific satellite mission for high energy gamma-ray, electron and cosmic rays detection. The silicon tracker (STK) is a sub detector of the DAMPE payload with an excellent position resolution (readout pitch of 242um), which measures the incident direction of p...
1503.00415v1
2015-03-08
MHD Seismology of a loop-like filament tube by observed kink waves
We report and analyze the observational evidence of global kink oscillations in a solar filament as observed in H alpha by National Solar Observatory (NSO)/Global Oscillation Network Group (GONG) instrument. An M1.1-class flare in active region 11692 on 2013 March 15 induced a global kink mode in the filament lying in ...
1503.02281v1
2015-03-13
Comparison of spin-orbit torques and spin pumping across NiFe/Pt and NiFe/Cu/Pt interfaces
We experimentally investigate spin-orbit torques and spin pumping in NiFe/Pt bilayers with direct and interrupted interfaces. The damping-like and field-like torques are simultaneously measured with spin-torque ferromagnetic resonance tuned by a dc bias current, whereas spin pumping is measured electrically through the...
1503.04104v3
2015-03-24
Global weak solutions to compressible quantum Navier-Stokes equations with damping
The global-in-time existence of weak solutions to the barotropic compressible quantum Navier-Stokes equations with damping is proved for large data in three dimensional space. The model consists of the compressible Navier-Stokes equations with degenerate viscosity, and a nonlinear third-order differential operator, wit...
1503.06894v4
2015-03-30
Suppression of Spin Pumping Between Ni$_{80}$Fe$_{20}$ and Cu by a Graphene Interlayer
We compare ferromagnetic resonance measurements of Permalloy Ni$_{80}$Fe$_{20}$ (Py) films sputtered onto Cu(111) films with and without a graphene (Gr) interlayer grown by chemical vapor deposition before Py deposition. A two-angle sputtering method ensured that neither Gr nor Py was degraded by the sample preparation...
1503.08777v1
2015-04-02
Protecting the $\sqrt{SWAP}$ operation from general and residual errors by continuous dynamical decoupling
We study the occurrence of errors in a continuously decoupled two-qubit state during a $\sqrt{SWAP}$ quantum operation under decoherence. We consider a realization of this quantum gate based on the Heisenberg exchange interaction, which alone suffices for achieving universal quantum computation. Furthermore, we introdu...
1504.00592v1
2015-04-07
Damped Oscillating Dark Energy: Ideal Fluid and Scalar-Tensor description
In this paper, we study damped oscillating form of dark energy for explaining dynamics of universe. First of all, we consider universe is filled with an ideal fluid which has damped oscillating dark energy in terms of this case we calculate several physical quantities such as Hubble parameter, acceleration parameter, e...
1504.01509v2
2015-04-17
Temperature-dependent Plasmons and Their Damping Rates for Graphene with a Finite Energy Bandgap
We obtained numerical and closed-form analytic expressions for finite-temperature plasmon dispersion relations for intrinsic graphene in the presence of a finite energy gap in the energy spectrum. The calculations were carried out using the random-phase approximation. The analytic results have been derived in the high ...
1504.04552v1
2015-05-09
Existence, general decay and blow-up of solutions for a viscoelastic Kirchhoff equation with Balakrishnan-Taylor damping and dynamic boundary conditions
Our aim in this article is to study a nonlinear viscoelastic Kirchhoff equation with strong damping, Balakrishnan-Taylor damping, nonlinear source and dynamical boundary condition. Firstly, we prove the local existence of solutions by using the Faedo-Galerkin approximation method combined with a contraction mapping the...
1505.02220v3
2015-06-03
Migration of two massive planets into (and out of) first order mean motion resonances
We consider the dynamical evolution of two planets orbiting in the vicinity of a first order mean motion reso- nance while simultaneously undergoing eccentricity damping and convergent migration. Following Goldreich & Schlichting (2014), we include a coupling between the dissipative semimajor axis evolution and the dam...
1506.01382v1
2015-06-12
Linear inviscid damping for monotone shear flows in a finite periodic channel, boundary effects, blow-up and critical Sobolev regularity
In a previous article, \cite{Zill3}, we have established linear inviscid damping for a large class of monotone shear flows in a finite periodic channel and have further shown that boundary effects asymptotically lead to the formation of singularities of derivatives of the solution. As the main results of this article, ...
1506.04010v1
2015-06-12
Nonlinear damped partial differential equations and their uniform discretizations
We establish sharp energy decay rates for a large class of nonlinearly first-order damped systems, and we design discretization schemes that inherit of the same energy decay rates, uniformly with respect to the space and/or time discretization parameters, by adding appropriate numerical viscosity terms. Our main argume...
1506.04163v2
2015-06-17
Landau Damping of Electrostatic Waves in Arbitrarily Degenerate Quantum Plasmas
We carry out a systematic study of the dispersion relation for linear electrostatic waves in an arbitrarily degenerate quantum electron plasma. We solve for the complex frequency spectrum for arbitrary values of wavenumber $k$ and level of degeneracy $\mu$. Our finding is that for large $k$ and high $\mu$ the real part...
1506.05494v2
2015-06-25
Simultaneous Interconnection and Damping Assignment Passivity-based Control of Mechanical Systems Using Generalized Forces
To extend the realm of application of the well known controller design technique of interconnection and damping assignment passivity-based control (IDA-PBC) of mechanical systems two modifications to the standard method are presented in this article. First, similarly to [1], it is proposed to avoid the splitting of the...
1506.07679v1
2015-07-20
Bifurcation of the quasinormal spectrum and Zero Damped Modes for rotating dilatonic black holes
It has been recently found that for the near extremal Kerr black holes appearing of Zero Damped Modes (accompanied by qusinormal mode branching) signifies about inapplicability of the regime of small perturbations and the onset of turbulence. Here we show that this phenomena is not limited by Kerr or Kerr-Newman soluti...
1507.05649v1
2015-07-24
Effect of Landau damping on alternative ion-acoustic solitary waves in a magnetized plasma consisting of warm adiabatic ions and non-thermal electrons
Bandyopadhyay and Das [Phys. Plasmas, 9, 465-473, 2002] have derived a nonlinear macroscopic evolution equation for ion acoustic wave in a magnetized plasma consisting of warm adiabatic ions and non-thermal electrons including the effect of Landau damping. In that paper they have also derived the corresponding nonlinea...
1507.06733v1
2015-08-05
Quantum discord protection from amplitude damping decoherence
Entanglement is known to be an essential resource for many quantum information processes. However, it is now known that some quantum features may be acheived with quantum discord, a generalized measure of quantum correlation. In this paper, we study how quantum discord, or more specifically, the measures of entropic di...
1508.00972v1
2015-09-03
Stability analysis of degenerately-damped oscillations
Presented here is a study of well-posedness and asymptotic stability of a "degenerately damped" PDE modeling a vibrating elastic string. The coefficient of the damping may vanish at small amplitudes thus weakening the effect of the dissipation. It is shown that the resulting dynamical system has strictly monotonically ...
1509.00917v1
2015-09-27
On the well-posedness and asymptotic behavior of the generalized KdV-Burgers equation
In this paper we are concerned with the well-posedness and the exponential stabilization of the generalized Korteweg-de Vries Burgers equation, posed on the whole real line, under the effect of a damping term. Both problems are investigated when the exponent p in the nonlinear term ranges over the interval $[1,5)$. We ...
1509.08148v1
2015-10-11
Error estimates of finite element method for semi-linear stochastic strongly damped wave equation
In this paper, we consider a semi-linear stochastic strongly damped wave equation driven by additive Gaussian noise. Following a semigroup framework, we establish existence, uniqueness and space-time regularity of a mild solution to such equation. Unlike the usual stochastic wave equation without damping, the underlyin...
1510.03028v1
2015-10-13
Nonlocal torque operators in ab initio theory of the Gilbert damping in random ferromagnetic alloys
We present an ab initio theory of the Gilbert damping in substitutionally disordered ferromagnetic alloys. The theory rests on introduced nonlocal torques which replace traditional local torque operators in the well-known torque-correlation formula and which can be formulated within the atomic-sphere approximation. The...
1510.03571v2
2015-11-10
A study of energy correction for the electron beam data in the BGO ECAL of the DAMPE
The DArk Matter Particle Explorer (DAMPE) is an orbital experiment aiming at searching for dark matter indirectly by measuring the spectra of photons, electrons and positrons originating from deep space. The BGO electromagnetic calorimeter is one of the key sub-detectors of the DAMPE, which is designed for high energy ...
1511.02998v1
2015-11-10
Quantum Fisher and Skew information for Unruh accelerated Dirac qubit
We develop a Bloch vector representation of Unruh channel for a Dirac field mode. This is used to provide a unified, analytical treatment of quantum Fisher and Skew information for a qubit subjected to the Unruh channel, both in its pure form as well as in the presence of experimentally relevant external noise channels...
1511.03029v1
2015-11-23
Detection of high frequency oscillations and damping from multi-slit spectroscopic observations of the corona
During the total solar eclipse of 11 July 2010, multi-slit spectroscopic observations of the solar corona were performed from Easter Island, Chile. To search for high-frequency waves, observations were taken at a high cadence in the green line at 5303 A due to [Fe xiv] and the red line at 6374 A due to [Fe x]. The data...
1511.07160v1
2015-11-26
Uniform exponential stability of Galerkin approximations for damped wave systems
We consider the numerical approximation of linear damped wave systems by Galerkin approximations in space and appropriate time-stepping schemes. Based on a dissipation estimate for a modified energy, we prove exponential decay of the physical energy on the continuous level provided that the damping is effective everywh...
1511.08341v1
2015-12-01
Epitaxial patterning of nanometer-thick Y3Fe5O12 films with low magnetic damping
Magnetic insulators such as yttrium iron garnet, Y3Fe5O12, with extremely low magnetic damping have opened the door for low power spin-orbitronics due to their low energy dissipation and efficient spin current generation and transmission. We demonstrate reliable and efficient epitaxial growth and nanopatterning of Y3Fe...
1512.00286v1
2015-12-03
Probing Bogoliubov quasiparticles in superfluid $^3$He with a 'vibrating-wire like' MEMS device
We have measured the interaction between superfluid $^3$He-B and a micro-machined goalpost-shaped device at temperatures below $0.2\,T_c$. The measured damping follows well the theory developed for vibrating wires, in which the Andreev reflection of quasiparticles in the flow field around the moving structure leads to ...
1512.01033v1
2016-01-03
Event-triggered Communication in Wide-area Damping Control: A Limited Output Feedback Based Approach
A conceptual design methodology is proposed for event-triggered based power system wide area damping controller. The event-triggering mechanism is adopted to reduce the communication burden between origin of the remote signal and the wide area damping controller (WADC) location. The remote signal is transmitted to the ...
1601.00255v1
2016-01-05
Lie transformation method on quantum state evolution of a general time-dependent driven and damped parametric oscillator
A variety of dynamics in nature and society can be approximately treated as a driven and damped parametric oscillator. An intensive investigation of this time-dependent model from an algebraic point of view provides a consistent method to resolve the classical dynamics and the quantum evolution in order to understand t...
1601.00727v3
2016-02-19
Distinctive response of many-body localized systems to strong electric field
We study systems which are close to or within the many-body localized (MBL) regime and are driven by strong electric field. In the ergodic regime, the disorder extends applicability of the equilibrium linear--response theory to stronger drivings, whereas the response of the MBL systems is very distinctive, revealing cu...
1602.06055v1
2016-02-24
Pressure of a gas of underdamped active dumbbells
The pressure exerted on a wall by a gas at equilibrium does not depend on the shape of the confining potential defining the wall. In contrast, it has been shown recently [A.P. Solon et al., Nat. Phys. 11, 673 (2015)] that a gas of overdamped active particles exerts on a wall a force that depends on the confining potent...
1602.07420v1
2016-03-07
Optimal Load and Stiffness for Displacement-Constrained Vibration Energy Harvesters
The power electronic interface to a vibration energy harvester not only provides ac-dc conversion, but can also set the electrical damping to maximize output power under displacement-constrained operation. This is commonly exploited for linear two-port harvesters by synchronous switching to realize a Coulomb-damped res...
1603.01909v1
2016-03-22
Generation and protection of steady-state quantum correlations due to quantum channels with memory
We have proposed a scheme of the generation and preservation of two-qubit steady state quantum correlations through quantum channels where successive uses of the channels are correlated. Different types of noisy channels with memory, such as amplitude damping, phase-damping, and depolarizing channels have been taken in...
1603.06676v2
2016-03-31
Recovery of time-dependent damping coefficients and potentials appearing in wave equations from partial data
We consider the inverse problem of determining a time-dependent damping coefficient $a$ and a time-dependent potential $q$, appearing in the wave equation $\partial_t^2u-\Delta_x u+a(t,x)\partial_tu+q(t,x)u=0$ in $Q=(0,T)\times\Omega$, with $T>0$ and $\Omega$ a $ \mathcal C^2$ bounded domain of $\mathbb R^n$, $n\geq2$,...
1603.09600v2
2016-04-22
Feedback-induced Bistability of an Optically Levitated Nanoparticle: A Fokker-Planck Treatment
Optically levitated nanoparticles have recently emerged as versatile platforms for investigating macroscopic quantum mechanics and enabling ultrasensitive metrology. In this article we theoretically consider two damping regimes of an optically levitated nanoparticle cooled by cavityless parametric feedback. Our treatme...
1604.06767v2
2016-05-06
Multidimensional Thermoelasticity for Nonsimple Materials -- Well-Posedness and Long-Time Behavior
An initial-boundary value problem for the multidimensional type III thermoelaticity for a nonsimple material with a center of symmetry is considered. In the linear case, the well-posedness with and without Kelvin-Voigt and/or frictional damping in the elastic part as well as the lack of exponential stability in the ela...
1605.02049v1
2016-05-16
The Cauchy problem for the nonlinear damped wave equation with slowly decaying data
We study the Cauchy problem for the nonlinear damped wave equation and establish the large data local well-posedness and small data global well-posedness with slowly decaying initial data. We also prove that the asymptotic profile of the global solution is given by a solution of the corresponding parabolic problem, whi...
1605.04616v2
2016-05-20
High-frequency behavior of FeN thin films fabricated by reactive sputtering
We investigated high-frequency behavior of FeN thin films prepared by reactive sputtering through ferromagnetic resonance (FMR) and its relationship with the static magnetic properties. The FMR was observed in the frequency range from 2 to 18 GHz in the FeN films fabricated at proper nitrogen flow rate (NFR). In those ...
1605.06179v1
2016-06-08
Effect of quantum noise on deterministic joint remote state preparation of a qubit state via a GHZ channel
Quantum secure communication brings a new direction for information security. As an important component of quantum secure communication, deterministic joint remote state preparation (DJRSP) could securely transmit a quantum state with 100\% success probability. In this paper, we study how the efficiency of DJRSP is aff...
1606.02484v2
2016-06-28
Radiation Damping by Thomson Scattering
Synchrotron radiation of relativistic electrons in storage rings naturally leads to the process of damping of betatron oscillations. Damping time and transverse beam emittance can be reduced by wigglers or undulators while the beam parameters are still well defined by the common radiation integrals, based on the proper...
1606.08602v5
2016-06-29
Kinodynamic Motion Planning: A Novel Type Of Nonlinear, Passive Damping Forces And Advantages
This article extends the capabilities of the harmonic potential field approach to planning to cover both the kinematic and dynamic aspects of a robot motion. The suggested approach converts the gradient guidance field from a harmonic potential to a control signal by augmenting it with a novel type of damping forces cal...
1606.09270v1
2016-07-18
Magnetic Skyrmion Transport in a Nanotrack With Spatially Varying Damping and Non-adiabatic Torque
Reliable transport of magnetic skyrmions is required for any future skyrmion-based information processing devices. Here we present a micromagnetic study of the in-plane current-driven motion of a skyrmion in a ferromagnetic nanotrack with spatially sinusoidally varying Gilbert damping and/or non-adiabatic spin-transfer...
1607.04983v3
2016-07-20
Envelope equation for the linear and nonlinear propagation of an electron plasma wave, including the effects of Landau damping, trapping, plasma inhomogeneity, and the change in the state of wave
This paper addresses the linear and nonlinear three-dimensional propagation of an electron wave in a collisionless plasma that may be inhomogeneous, nonstationary, anisotropic and even weakly magnetized. The wave amplitude, together with any hydrodynamic quantity characterizing the plasma (density, temperature,...) are...
1607.05844v2
2016-09-02
Particle dynamics and Stochastic Resonance in Periodic potentials
We have studied the dynamics of a particle in a periodically driven underdamped periodic potential. Recent studies have reported the occurrence of Stochastic Resonance (SR) in such systems in the high frequency regime, using input energy per period of external drive as a quantifier. The particle trajectories in these s...
1609.00678v1
2016-09-26
An efficient quantum algorithm for spectral estimation
We develop an efficient quantum implementation of an important signal processing algorithm for line spectral estimation: the matrix pencil method, which determines the frequencies and damping factors of signals consisting of finite sums of exponentially damped sinusoids. Our algorithm provides a quantum speedup in a na...
1609.08170v1
2016-10-01
On the regularization of impact without collision: the Painlevé paradox and compliance
We consider the problem of a rigid body, subject to a unilateral constraint, in the presence of Coulomb friction. We regularize the problem by assuming compliance (with both stiffness and damping) at the point of contact, for a general class of normal reaction forces. Using a rigorous mathematical approach, we recover ...
1610.00143v2
2016-10-21
Spin transport and dynamics in all-oxide perovskite La$_{2/3}$Sr$_{1/3}$MnO$_3$/SrRuO$_3$ bilayers probed by ferromagnetic resonance
Thin films of perovskite oxides offer the possibility of combining emerging concepts of strongly correlated electron phenomena and spin current in magnetic devices. However, spin transport and magnetization dynamics in these complex oxide materials are not well understood. Here, we experimentally quantify spin transpor...
1610.06661v1
2016-11-25
Bulk viscous corrections to screening and damping in QCD at high temperatures
Non-equilibrium corrections to the distribution functions of quarks and gluons in a hot and dense QCD medium modify the "hard thermal loops" (HTL). The HTLs determine the retarded, advanced, and symmetric (time-ordered) propagators for gluons with soft momenta as well as the Debye screening and Landau damping mass scal...
1611.08379v2
2016-12-07
Investigation of Stimulated Brillouin Scattering in Laser-Plasma Interactions
In this paper, we present our numerical simulation results on the Stimulated Brillouin Scattering (SBS) with injection of an ordinary mode (O-mode) electromagnetic wave (our pump wave) with frequencies 70 GHz and 110 GHz. Solving the Fourier transformed Vlasov equation in the velocity space, creates a profile for distr...
1612.02214v1
2016-12-07
Gilbert damping of magnetostatic modes in a yttrium iron garnet sphere
The magnetostatic mode (MSM) spectrum of a 300$\mu$m diameter single crystalline sphere of yttrium iron garnet is investigated using broadband ferromagnetic resonance (FMR). The individual MSMs are identified via their characteristic dispersion relations and the corresponding mode number tuples $(nmr)$ are assigned. Ta...
1612.02360v1
2016-12-08
Damped spin-wave excitations in the itinerant antiferromagnet $γ$-Fe$_{0.7}$Mn$_{0.3}$
The collective spin-wave excitations in the antiferromagnetic state of $\gamma$-Fe$_{0.7}$Mn$_{0.3}$ were investigated using the inelastic neutron scattering technique. The spin excitations remain isotropic up to the high excitation energy, ${\hbar\omega}= 78$ meV. The excitations gradually become broad and damped abov...
1612.02515v2
2016-12-09
How strong a logistic damping can prevent blow-up for the minimal Keller-Segel chemotaxis system?
In this paper, we study the minimal Keller-Segel model with a logistic source and obtain quantitative and qualitative descriptions of the competition between logistic damping and other ingredient, especially, chemotactic aggregation to guarantee boundedness and convergence. More specifically, we establish how precisely...
1612.03024v2