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2017-09-13
Effects of pressure on suspended micromechanical membrane arrays
The effects of pressure on micromechanical air-filled cavities made by a pair of suspended, parallel silicon nitride membranes are investigated in the free molecular and quasi-molecular regimes. Variations of the fundamental drummode mechanical resonant frequencies and damping with air pressure are determined by means ...
1710.00043v2
2017-10-11
Parametric Decay Instability and Dissipation of Low-frequency Alfvén Waves in Low-beta Turbulent Plasmas
Evolution of the parametric decay instability (PDI) of a circularly polarized Aflv\'en wave in a turbulent low-beta plasma background is investigated using 3D hybrid simulations. It is shown that the turbulence reduces the growth rate of PDI as compared to the linear theory predictions, but PDI can still exist. Interes...
1710.04149v3
2017-10-14
Doubly Damped Stochastic Parallel Translations and Hessian Formulas
We study the Hessian of the solutions of time-independent Schr\"odinger equations, aiming to obtain as large a class as possible of complete Riemannian manifolds for which the estimate $C(\frac 1 t +\frac {d^2}{t^2})$ holds. For this purpose we introduce the doubly damped stochastic parallel transport equation, study t...
1710.05169v1
2017-10-20
Magnetic field amplification in supernova remnants
Based on the new findings on the turbulent dynamo in \citet{XL16}, we examine the magnetic field amplification in the context of supernova remnants. Due to the strong ion-neutral collisional damping in the weakly-ionized interstellar medium, the dynamo in the preshock turbulence remains in the damping kinematic regime,...
1710.07717v1
2017-10-26
Coarse-graining in the derivation of Markovian master equations and its significance in quantum thermodynamics
The coarse-graining approach to deriving the quantum Markovian master equation is revisited, with close attention given to the underlying approximations. It is further argued that the time interval over which the coarse-graining is performed is a free parameter that can be given a physical measurement-based interpretat...
1710.09939v2
2017-10-27
The Marangoni effect on small-amplitude capillary waves in viscous fluids
We derive a general integrodifferential equation for the transient behaviour of small-amplitude capillary waves on the planar surface of a viscous fluid in the presence of the Marangoni effect. The equation is solved for an insoluble surfactant solution in concentration below the critical micelle concentration (cmc) un...
1710.10137v1
2017-11-03
Remark on upper bound for lifespan of solutions to semilinear evolution equations in a two-dimensional exterior domain
In this paper we consider the initial-boundary value problem for the heat, damped wave, complex-Ginzburg-Landau and Schr"odinger equations with the power type nonlinearity $|u|^p$ with $p in (1,2]$ in a two-dimensional exterior domain. Remark that $2=1+2/N$ is well-known as the Fujita exponent. If $p>2$, then there exi...
1711.00994v1
2017-11-03
A flowing pair of particles in inertial microfluidics
A flowing pair of particles in inertial microfluidics gives important insights into understanding and controlling the collective dynamics of particles like cells or droplets in microfluidic devices. They are applied in medical cell analysis and engineering. We study the dynamics of a pair of solid particles flowing thr...
1711.01148v2
2017-11-07
Application of the coupled classical oscillators model to the Fano resonance build-up in a plasmonic nanosystem
We study the excitation dynamics of Fano resonance within the classical model framework of two linear coupled oscillators. An exact solution for the model with a damped harmonic force is obtained. The details of growth a Fano profile under the harmonic excitation is shown. For incident ultra-wideband pulse, the reactio...
1711.02498v2
2017-11-11
Quantum Thermodynamics for Driven Dissipative Bosonic Systems
We investigate two prototypical dissipative bosonic systems under slow driving and arbitrary system-bath coupling strength, recovering their dynamic evolution as well as the heat and work rates, and we verify that thermodynamic laws are respected. Specifically, we look at the damped harmonic oscillator and the damped t...
1711.04077v1
2017-11-29
Constraints on box-shaped cosmic ray electron feature from dark matter annihilation with the AMS-02 and DAMPE data
Precise measurements of spectra of cosmic ray electrons and positrons can effectively probe the nature of dark matter (DM) particles. In a class of models where DM particles initially annihilate into a pair of intermediate particles which then decay into standard model particles, box-shaped spectra can be generated. Su...
1711.11052v2
2017-11-30
TeV dark matter and the DAMPE electron excess
The recent high energy electron and positron flux observed by the DAMPE experiment indicates possible excess events near 1.4 TeV. Such an excess may be evidence of dark matter annihilations or decays in a dark matter subhalo that is located close to the solar system. We give here an analysis of this excess from annihil...
1711.11579v1
2017-12-04
Quasi-degenerate dark matter for DAMPE excess and $3.5\,\textrm{keV}$ line
We propose a quasi-degenerate dark matter scenario to simultaneously explain the $1.4\,\textrm{TeV}$ peak in the high-energy cosmic-ray electron-positron spectrum reported by the DAMPE collaboration very recently and the $3.5\,\textrm{keV}$ X-ray line observed in galaxies clusters and from the Galactic centre and confi...
1712.00922v1
2017-12-06
Collective modes of an imbalanced unitary Fermi gas
We study theoretically the collective mode spectrum of a strongly imbalanced two-component unitary Fermi gas in a cigar-shaped trap, where the minority species forms a gas of polarons. We describe the collective breathing mode of the gas in terms of the Fermi liquid kinetic equation taking collisions into account using...
1712.02181v1
2017-12-07
Bias of Damped Lyman-$α$ systems from their cross-correlation with CMB lensing
We cross-correlate the positions of damped Lyman-$\alpha$ systems (DLAs) and their parent quasar catalog with a convergence map derived from the Planck cosmic microwave background (CMB) temperature data. We make consistent measurements of the lensing signal of both samples in both Fourier and configuration space. By in...
1712.02738v2
2017-12-08
Viscoelastic optical nonlocality of low-loss epsilon-near-zero nanofilms
Optical nonlocalities are elusive and hardly observable in traditional plasmonic materials like noble and alkali metals. Here we report experimental observation of viscoelastic nonlocalities in the infrared optical response of doped cadmium-oxide, epsilon-near-zero nanofilms. The nonlocality is detectable thanks to the...
1712.03169v2
2017-12-08
A Strong Test of the Dark Matter Origin of the 1.4 TeV DAMPE Signal Using IceCube Neutrinos
A tentative excess in the electron spectrum at 1.4 TeV was recently reported by the DArk Matter Particle Explorer (DAMPE). A non-astrophysical scenario in which dark matter particles annihilate or decay in a local clump has been invoked to explain the excess. If $e^\pm$ annihilation channels in the final states are med...
1712.03210v2
2017-12-11
Prospects of type-II seesaw at future colliders in light of the DAMPE $e^+ e^-$ excess
The DAMPE $e^+ e^-$ excess at around 1.4 TeV could be explained in the type-II seesaw model with a scalar dark mater $D$ which is stabilized by a discrete $Z_2$ symmetry. The simplest scenario is the annihilation $DD \to H^{++} H^{--}$ followed by the subsequent decay $H^{\pm\pm} \to e^\pm e^\pm$, with both the DM and ...
1712.03642v3
2017-12-12
Thermal decoherence in a strongly correlated Bose liquid
We compute the single particle spectral function of a Bose liquid on a lattice, at integer filling, close to the superfluid-Mott transition. We use a `static path approximation' that retains all the classical thermal fluctuations in the problem, and a real space implementation of the random phase approximation (RPA) fo...
1712.04433v1
2017-12-17
Oscillation energy based sensitivity analysis and control for multi-mode oscillation systems
This paper describes a novel approach to analyze and control systems with multi-mode oscillation problems. Traditional single dominant mode analysis fails to provide effective control actions when several modes have similar low damping ratios. This work addresses this problem by considering all modes in the formulation...
1712.06157v1
2017-12-19
Nonequilibrium quantum solvation with a time-dependent Onsager cavity
We formulate a theory of nonequilibrium quantum solvation in which parameters of the solvent are explicitly depending on time. We assume in a simplest approach a spherical molecular Onsager cavity with a time-dependent radius. We analyze the relaxation properties of a test molecular point dipole in a dielectric solvent...
1712.06973v2
2017-12-26
Newton's equation of motion with quadratic drag force and Toda's potential as a solvable one
The family of exactly solvable potentials for Newton's equation of motion in the one-dimensional system with quadratic drag force has been determined completely. The determination is based on the implicit inverse-function solution valid for any potential shape, and hence exhaustive. This solvable family includes the ex...
1712.09189v4
2017-12-23
Density Fluctuations in the Solar Wind Driven by Alfvén Wave Parametric Decay
Measurements and simulations of inertial compressive turbulence in the solar wind are characterized by anti-correlated magnetic fluctuations parallel to the mean field and density structures. This signature has been interpreted as observational evidence for non-propagating pressure balanced structures (PBS), kinetic io...
1712.09336v2
2018-01-15
A radiative neutrino mass model in light of DAMPE excess with hidden gauged $U(1)$ symmetry
We propose a one-loop induced neutrino mass model with hidden $U(1)$ gauge symmetry, in which we successfully involve a bosonic dark matter (DM) candidate propagating inside a loop diagram in neutrino mass generation to explain the $e^+e^-$ excess recently reported by the DArk Matter Particle Explorer (DAMPE) experimen...
1801.04729v2
2018-01-22
A port-Hamiltonian approach to the control of nonholonomic systems
In this paper a method of controlling nonholonomic systems within the port-Hamiltonian (pH) framework is presented. It is well known that nonholonomic systems can be represented as pH systems without Lagrange multipliers by considering a reduced momentum space. Here, we revisit the modelling of these systems for the pu...
1801.06954v1
2018-01-23
Temperature gradient driven heat flux closure in fluid simulations of collisionless reconnection
Recent efforts to include kinetic effects in fluid simulations of plasmas have been very promising. Concerning collisionless magnetic reconnection, it has been found before that damping of the pressure tensor to isotropy leads to good agreement with kinetic runs in certain scenarios. An accurate representation of kinet...
1801.07628v1
2018-01-29
Oscillatory relaxation of zonal flows in a multi-species stellarator plasma
The low frequency oscillatory relaxation of zonal potential perturbations is studied numerically in the TJ-II stellarator (where it was experimentally detected for the first time). It is studied in full global gyrokinetic simulations of multi-species plasmas. The oscillation frequency obtained is compared with predicti...
1801.09495v1
2018-01-30
Input / Output Stability of a Damped String Equation coupled with Ordinary Differential System
The input/output stability of an interconnected system composed of an ordinary differential equation and a damped string equation is studied. Issued from the literature on time-delay systems, an exact stability result is firstly derived using pole locations. Then, based on the Small-Gain theorem and on the Quadratic Se...
1801.09916v2
2018-02-05
Intrinsic spin-orbit torque arising from Berry curvature in metallic-magnet/Cu-oxide interface
We report the observation of the intrinsic damping-like spin-orbit torque (SOT) arising from the Berry curvature in metallic-magnet/CuO$_x$ heterostructures. We show that a robust damping-like SOT, an order of magnitude larger than a field-like SOT, is generated in the heterostructure despite the absence of the bulk sp...
1802.01285v2
2018-02-12
Selective Phonon Damping in Topological Semimetals
Topological semimetals are characterized by their intriguing Fermi surfaces (FSs) such as Weyl and Dirac points, or nodal FS, and their associated surface states. Among them, topological crystalline semimetals, in the presence of strong spin-orbit coupling, possess a nodal FS protected by non-symmorphic lattice symmetr...
1802.04300v2
2018-02-14
Motion of interfaces for a damped hyperbolic Allen-Cahn equation
Consider the Allen-Cahn equation $u_t=\varepsilon^2\Delta u-F'(u)$, where $F$ is a double well potential with wells of equal depth, located at $\pm1$. There are a lot of papers devoted to the study of the limiting behavior of the solutions as the diffusion coefficient $\varepsilon\to0^+$, and it is well known that, if ...
1802.05038v1
2018-02-23
Blow up of solutions for semilinear wave equations with noneffective damping
In this paper, we study the finite-time blow up of solutions to the following semilinear wave equation with time-dependent damping \[ \partial_t^2u-\Delta u+\frac{\mu}{1+t}\partial_tu=|u|^p \] in $\mathbb{R}_{+}\times\mathbb{R}^n$. More precisely, for $0\leq\mu\leq 2,\mu \neq1$ and $n\geq 2$, there is no global solutio...
1802.08403v2
2018-03-04
Optimization of Time-Resolved Magneto-optical Kerr Effect Signals for Magnetization Dynamics Measurements
Recently magnetic storage and magnetic memory have shifted towards the use of magnetic thin films with perpendicular magnetic anisotropy (PMA). Understanding the magnetic damping in these materials is crucial, but normal Ferromagnetic Resonance (FMR) measurements face some limitations. The desire to quantify the dampin...
1803.01280v2
2018-03-06
A comparison of semi-Lagrangian discontinuous Galerkin and spline based Vlasov solvers in four dimensions
The purpose of the present paper is to compare two semi-Lagrangian methods in the context of the four-dimensional Vlasov--Poisson equation. More specifically, our goal is to compare the performance of the more recently developed semi-Lagrangian discontinuous Galerkin scheme with the de facto standard in Eulerian Vlasov...
1803.02143v1
2018-03-06
Kak's three-stage protocol of secure quantum communication revisited: Hitherto unknown strengths and weaknesses of the protocol
Kak's three-stage protocol for quantum key distribution is revisited with special focus on its hitherto unknown strengths and weaknesses. It is shown that this protocol can be used for secure direct quantum communication. Further, the implementability of this protocol in the realistic situation is analyzed by consideri...
1803.02157v1
2018-03-09
Dynamical evolutions in non-Hermitian triple-well system with complex potential
We investigate the dynamical properties for non-Hermitian triple-well system with a loss in the middle well. When chemical potentials in two end wells are uniform and nonlinear interactions are neglected, there always exists a dark state, whose eigenenergy becomes zero, and the projections onto which do not change over...
1803.03360v1
2018-03-11
Graph Laplacian Spectrum and Primary Frequency Regulation
We present a framework based on spectral graph theory that captures the interplay among network topology, system inertia, and generator and load damping in determining the overall grid behavior and performance. Specifically, we show that the impact of network topology on a power system can be quantified through the net...
1803.03905v3
2018-03-15
Control Inversion: A Clustering-Based Method for Distributed Wide-Area Control of Power Systems
Wide-area control (WAC) has been shown to be an effective tool for damping low-frequency oscillations in power systems. In the current state of art, WAC is challenged by two main factors - namely, scalability of design and complexity of implementation. In this paper we present a control design called control inversion ...
1803.05947v1
2018-03-18
Damped Anderson acceleration with restarts and monotonicity control for accelerating EM and EM-like algorithms
The expectation-maximization (EM) algorithm is a well-known iterative method for computing maximum likelihood estimates from incomplete data. Despite its numerous advantages, a main drawback of the EM algorithm is its frequently observed slow convergence which often hinders the application of EM algorithms in high-dime...
1803.06673v2
2018-03-21
Connectivity-Preserving Coordination Control of Multi-Agent Systems with Time-Varying Delays
This paper presents a distributed position synchronization strategy that also preserves the initial communication links for single-integrator multi-agent systems with time-varying delays. The strategy employs a coordinating proportional control derived from a specific type of potential energy, augmented with damping in...
1803.08152v1
2018-03-23
A Novel Approach to Resonant Absorption of the Fast MHD Eigenmodes of a Coronal Arcade
The arched field lines forming coronal arcades are often observed to undulate as magnetohydrodynamic (MHD) waves propagate both across and along the magnetic field. These waves are most likely a combination of resonantly coupled fast magnetoacoustic waves and Alfv\'en waves. The coupling results in resonant absorption ...
1803.08948v1
2018-03-25
Parareal exponential $θ$-scheme for longtime simulation of stochastic Schrödinger equations with weak damping
A parareal algorithm based on an exponential $\theta$-scheme is proposed for the stochastic Schr\"odinger equation with weak damping and additive noise. It proceeds as a two-level temporal parallelizable integrator with the exponential $\theta$-scheme as the propagator on the coarse grid. The proposed algorithm in the ...
1803.09188v1
2018-04-01
Aggregated Momentum: Stability Through Passive Damping
Momentum is a simple and widely used trick which allows gradient-based optimizers to pick up speed along low curvature directions. Its performance depends crucially on a damping coefficient $\beta$. Large $\beta$ values can potentially deliver much larger speedups, but are prone to oscillations and instability; hence o...
1804.00325v3
2018-04-03
Damped perturbations in the no-boundary state
We evaluate the no-boundary path integral exactly in a Bianchi IX minisuperspace with two scale factors. In this model the no-boundary proposal can be implemented by requiring one scale factor to be zero initially together with a judiciously chosen regularity condition on the momentum conjugate to the second scale fact...
1804.01102v2
2018-09-14
Nonequilibrium polariton dynamics in a Bose-Einstein condensate coupled to an optical cavity
We study quasiparticle scattering effects on the dynamics of a homogeneous Bose-Einstein condensate of ultracold atoms coupled to a single mode of an optical cavity. The relevant excitations, which are polariton-like mixed excitations of photonic and atomic density-wave modes, are identified. All the first-order correl...
1809.05427v2
2018-09-26
The influence of oscillations on energy estimates for damped wave models with time-dependent propagation speed and dissipation
The aim of this paper is to derive higher order energy estimates for solutions to the Cauchy problem for damped wave models with time-dependent propagation speed and dissipation. The model of interest is \begin{equation*} u_{tt}-\lambda^2(t)\omega^2(t)\Delta u +\rho(t)\omega(t)u_t=0, \quad u(0,x)=u_0(x), \,\, u_t(0,x)=...
1809.10179v2
2018-09-27
Non-equilibrium Quantum Langevin dynamics of orbital diamagnetic moment
We investigate the time dependent orbital diamagnetic moment of a charged particle in a magnetic field in a viscous medium via the Quantum Langevin Equation. We study how the interplay between the cyclotron frequency and the viscous damping rate governs the dynamics of the orbital magnetic moment in the high temperatur...
1809.10370v1
2018-10-31
AGN Variability Analysis Handbook
This work develops application techniques for stochastic modelling of Active Galactic Nuclei (AGN) variability as a probe of accretion disk physics. Stochastic models, specifically Continuous Auto-Regressive Moving Average (CARMA) models, characterize lightcurves by estimating delay timescales that describe movements a...
1811.00154v1
2018-11-15
Unique ergodicity for a class of stochastic hyperbolic equations with additive space-time white noise
In this paper, we consider a certain class of second order nonlinear PDEs with damping and space-time white noise forcing, posed on the $d$-dimensional torus. This class includes the wave equation for $d=1$ and the beam equation for $d\le 3$. We show that the Gibbs measure of the equation without forcing and damping is...
1811.06294v4
2018-12-04
Optical excitation of single- and multi-mode magnetization precession in Galfenol nanolayers
We demonstrate a variety of precessional responses of the magnetization to ultrafast optical excitation in nanolayers of Galfenol (Fe,Ga), which is a ferromagnetic material with large saturation magnetization and enhanced magnetostriction. The particular properties of Galfenol, including cubic magnetic anisotropy and w...
1812.01237v1
2018-12-10
Assessment of skin-friction-reduction techniques on a turbulent wing section
The scope of the present project is to quantify the effects of uniform blowing and body-force damping on turbulent boundary layers subjected to a non-uniform adverse-pressure-gradient distribution. To this end, well-resolved large-eddy simulations are employed to describe the flow around the NACA4412 airfoil at moderat...
1812.03762v1
2018-12-18
Gravitational quasinormal modes of black holes in Einstein-aether theory
The local Lorentz violation (LV) in gravity sector should show itself in derivation of the characteristic quasinormal modes (QNMs) of black hole mergers from their general relativity case. In this paper, I study QNMs of the gravitational field perturbations to Einstein-aether black holes and, at first compare them to t...
1812.07994v1
2018-12-19
Rain Calms the Sea - The Impact of Entrained Air
We propose a mechanism for the damping of short ocean gravity waves during rainstorms associated with the injection of air bubbles by rain drops. The mechanism is proposed as one of the possible explanations that ascribe to rain a calming effect on ocean surface waves. A model is developed that shows how wave attenuati...
1812.08200v2
2018-12-25
Blow-up for a weakly coupled system of semilinear damped wave equations in the scattering case with power nonlinearities
In this work we study the blow-up of solutions of a weakly coupled system of damped semilinear wave equations in the scattering case with power nonlinearities. We apply an iteration method to study both the subcritical case and the critical case. In the subcritical case our approach is based on lower bounds for the spa...
1812.10086v1
2018-12-27
Global existence of solutions to semilinear damped wave equation with slowly decaying inital data in exterior domain
In this paper, we discuss the global existence of weak solutions to the semilinear damped wave equation \begin{equation*} \begin{cases} \partial_t^2u-\Delta u + \partial_tu = f(u) & \text{in}\ \Omega\times (0,T), \\ u=0 & \text{on}\ \partial\Omega\times (0,T), \\ u(0)=u_0, \partial_tu(0)=u_1 & \text{in}\ \Omega, \end{c...
1812.10664v1
2019-02-08
Milky Way Halo Vibrations and Incommensurate Stream Velocities
Collisionless dark matter galactic halos are expected to exhibit damped oscillations as a result of ongoing late time accretion. An n-body model of the cosmological assembly of a Milky Way-like halo is used to quantify the time dependence of its gravitational field. The simulation contains stellar streams whose incomme...
1902.03275v2
2019-02-20
Dark matter gets DAMPE at high energies
The DArk Matter Particle Explorer (DAMPE) mission revealed a break in the spectrum of cosmic-ray electons and positrons. This is associated with an excess above the expected backgrounds at energies around 1 TeV. Several authors have argued that such an excess can be explained in terms of dark matter models that feature...
1902.07468v1
2019-02-23
General symmetry in the reduced dynamics of two-level system
We study general transformation on the density matrix of two-level system that keeps the expectation value of observable invariant. We introduce a set of generators that yields hermiticity and trace preserving general transformation which casts the transformation into simple form. The general transformation is in gener...
1902.08714v2
2019-02-25
Interpretation of the cosmic ray positron and electron excesses with an annihilating-decaying dark matter scenario
The precise measurements of energy spectra of cosmic ray positrons and/or electrons by recent experiments show clear excesses above 10 GeV. Moreover, a potential sharp spectral feature was suggested by the Dark Matter Particle Explorer (DAMPE) data. These results inspire quite a number of discussions on the connection ...
1902.09235v2
2019-02-27
Necessary and Sufficient Conditions for Passivity of Velocity-Sourced Impedance Control of Series Elastic Actuators
Series Elastic Actuation (SEA) has become prevalent in applications involving physical human-robot interaction as it provides considerable advantages over traditional stiff actuators in terms of stability robustness and fidelity of force control. Several impedance control architectures have been proposed for SEA. Among...
1902.10607v2
2019-03-01
Response to: [Comment on Quantization of the damped harmonic oscillator [Serhan et al, J. Math. Phys. 59, 082105 (2018)]]
This is a response to a recently reported comment [1] on paper [J. Math. Phys.59, 082105 (2018)] regarding the quantization of damped harmonic oscillator using a non-Hermitian Hamiltonian with real energy eigenvalues. We assert here that the calculation of Eq. (29) of [2] is incorrect, and thus the subsequent steps via...
1903.00352v2
2019-03-07
Current-induced motion of twisted skyrmions
Twisted skyrmions, whose helicity angles are different from that of Bloch skyrmions and N\'eel skyrmions, have already been demonstrated in experiments recently. In this work, we first contrast the magnetic structure and origin of the twisted skyrmion with other three types of skyrmion including Bloch skyrmion, N\'eel ...
1903.02812v1
2019-03-08
Protecting quantum correlations in presence of generalised amplitude damping channel: the two-qubit case
Any kind of quantum resource useful in different information processing tasks is vulnerable to several types of environmental noise. Here we study the behaviour of quantum correlations such as entanglement and steering in two-qubit systems under the application of the generalised amplitude damping channel and propose s...
1903.03550v2
2019-03-17
Generalized Euler, Smoluchowski and Schrödinger equations admitting self-similar solutions with a Tsallis invariant profile
The damped isothermal Euler equations, the Smoluchowski equation and the damped logarithmic Schr\"odinger equation with a harmonic potential admit stationary and self-similar solutions with a Gaussian profile. They satisfy an $H$-theorem for a free energy functional involving the von Weizs\"acker functional and the Bol...
1903.07111v1
2019-03-21
Creating localized plasma wave by ionization of doped semiconductors
Localized plasma waves can be generated by suddenly ionizing extrinsic semiconductors with spatially periodic dopant densities. The built-in electrostatic potentials at the metallurgical junctions, combined with electron density ripples, offer the exact initial condition for exciting long-lasting plasma waves upon ioni...
1903.09013v2
2019-03-22
Noncommutative approach to diagnose degenerate Higgs bosons at 125 GeV
We propose a noncommutative (NC) version for a global O(2) scalar field theory, whose damping feature is introduced into the scalar field theory through the NC parameter. In this context, we investigate how noncommutative drives spontaneous symmetry breaking (SSB) and Higgs-Kibble mechanisms and how the damping feature...
1903.09727v2
2019-05-02
The floatability of aerosols and waves damping on Titan's seas
Titan, Saturn's largest moon, has a dense atmosphere, together with lakes and seas of liquid hydrocarbons. These liquid bodies, which are in polar regions and up to several hundred kilometres in diameter, generally have smooth surfaces despite evidence of near-surface winds. Photochemically generated organic aerosols f...
1905.00760v1
2019-05-02
Holographic Plasmon Relaxation with and without Broken Translations
We study the dynamics and the relaxation of bulk plasmons in strongly coupled and quantum critical systems using the holographic framework. We analyze the dispersion relation of the plasmonic modes in detail for an illustrative class of holographic bottom-up models. Comparing to a simple hydrodynamic formula, we entang...
1905.00804v2
2019-05-05
Effective spin-mixing conductance of heavy-metal-ferromagnet interfaces
The effective spin-mixing conductance (G_eff) of a heavy metal/ferromagnet (HM/FM) interface characterizes the efficiency of the interfacial spin transport.Accurately determining G_eff is critical to the quantitative understanding of measurements of direct and inverse spin Hall effects. G_eff is typically ascertained f...
1905.01577v2
2019-05-07
Integral representation formulae for the solution of a wave equation with time-dependent damping and mass in the scale-invariant case
This paper is devoted to derive integral representation formulae for the solution of an inhomogeneous linear wave equation with time-dependent damping and mass terms, that are scale-invariant with respect to the so-called hyperbolic scaling. Yagdjian's integral transform approach is employed for this purpose. The main ...
1905.02408v1
2019-05-07
Optimal decay for the $n$-dimensional incompressible Oldroyd-B model without damping mechanism
By a new energy approach involved in the high frequencies and low frequencies decomposition in the Besov spaces, we obtain the optimal decay for the incompressible Oldroyd-B model without damping mechanism in $\mathbb{R}^n$ ($n\ge 2$). More precisely, let $(u,\tau)$ be the global small solutions constructed in [18], ...
1905.02604v1
2019-05-12
Transport and Phonon Damping in $^{\bf 4}$He
The dynamic structure function $S(k,\omega)$ informs about the dispersion and damping of excitations. We have recently (Phys. Rev. B {\bf 97}, 184520 (2018)) compared experimental results for $S(k,\omega)$ from high-precision neutron scattering experiment and theoretical results using the ``dynamic many-body theory'' (...
1905.04759v1
2019-05-15
Nearly Markovian maps and entanglement-based bound on corresponding non-Markovianity
We identify a set of dynamical maps of open quantum system, and refer to them as "$ \epsilon $-Markovian" maps. It is constituted of maps which, in a higher dimensional system-environment Hilbert space, possibly violate Born approximation but only a "little". We characterize the "$\epsilon$-nonmarkovianity" of a genera...
1905.06198v3
2019-05-15
A remark on triviality for the two-dimensional stochastic nonlinear wave equation
We consider the two-dimensional stochastic damped nonlinear wave equation (SdNLW) with the cubic nonlinearity, forced by a space-time white noise. In particular, we investigate the limiting behavior of solutions to SdNLW with regularized noises and establish triviality results in the spirit of the work by Hairer, Ryser...
1905.06278v3
2019-05-17
Chiral p-wave superconductors have complex coherence and magnetic field penetration lengths
We show that in superconductors that break time reversal symmetry and have anisotropy, such as p+ip materials, all order parameters and magnetic modes are mixed. Excitation of the gap fields produces an excitation of the magnetic field and vice versa. Correspondingly the long-range decay of the magnetic field and order...
1905.07296v2
2019-05-20
Short time blow-up by negative mass term for semilinear wave equations with small data and scattering damping
In this paper we study blow-up and lifespan estimate for solutions to the Cauchy problem with small data for semilinear wave equations with scattering damping and negative mass term. We show that the negative mass term will play a dominant role when the decay of its coefficients is not so fast, thus the solutions will ...
1905.08100v1
2019-05-21
Low-pass-filter-based shock response spectrum and the evaluation method of transmissibility between equipment and sensitive components interfaces
According to the features of the sources of pyroshock and ballistic shock, this study considers the pyroshock and ballistic shock generated by their respective impulsive sources as damped harmonic waves with different frequencies. According to the linear superposition assumption of damped harmonic waves in a linear ela...
1905.10190v1
2019-05-24
Sound damping in glasses: interplay between anharmonicities and elastic heterogeneities
Some facets of the way sound waves travel through glasses are still unclear. Recent works have shown that in the low-temperature harmonic limit a crucial role in controlling sound damping is played by local elastic heterogeneity. Sound waves propagation has been demonstrated to be strongly affected by inhomogeneous mec...
1905.10235v2
2019-05-27
A blow-up result for a semilinear wave equation with scale-invariant damping and mass and nonlinearity of derivative type
In this note, we prove blow-up results for semilinear wave models with damping and mass in the scale-invariant case and with nonlinear terms of derivative type. We consider the single equation and the weakly coupled system. In the first case we get a blow-up result for exponents below a certain shift of the Glassey exp...
1905.11025v2
2019-05-28
Stationary states for underdamped anharmonic oscillators driven by Cauchy noise
Using methods of stochastic dynamics, we have studied stationary states in the underdamped anharmonic stochastic oscillators driven by Cauchy noise. Shape of stationary states depend both on the potential type and the damping. If the damping is strong enough, for potential wells which in the overdamped regime produce m...
1905.12078v2
2019-08-01
The $J$-method for the Gross-Pitaevskii eigenvalue problem
This paper studies the $J$-method of [E. Jarlebring, S. Kvaal, W. Michiels. SIAM J. Sci. Comput. 36-4:A1978-A2001, 2014] for nonlinear eigenvector problems in a general Hilbert space framework. This is the basis for variational discretization techniques and a mesh-independent numerical analysis. A simple modification o...
1908.00333v2
2019-08-02
How do Conservative Backbone Curves Perturb into Forced Responses? A Melnikov Function Analysis
Weakly damped mechanical systems under small periodic forcing tend to exhibit periodic response in a close vicinity of certain periodic orbits of their conservative limit. Specifically, amplitude frequency plots for the conservative limit have often been noted, both numerically and experimentally, to serve as backbone ...
1908.00721v3
2019-08-05
Tunable strong coupling of two adjacent optical λ/2 Fabry-Pérot microresonators
Optical half-wave microresonators enable to control the optical mode density around a quantum system and thus to modify the temporal emission properties. If the coupling rate exceeds the damping rate, strong coupling between a microresonator and a quantum system can be achieved, leading to a coherent energy exchange an...
1908.01566v1
2019-07-27
An extension of the second order dynamical system that models Nesterov's convex gradient method
In this paper we deal with a general second order continuous dynamical system associated to a convex minimization problem with a Fr\`echet differentiable objective function. We show that inertial algorithms, such as Nesterov's algorithm, can be obtained via the natural explicit discretization from our dynamical system....
1908.02574v1
2019-08-07
Interfacial contributions to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers
The thickness dependence of spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers is studied using the first-principles non-equilibrium Green's function formalism combined with the Anderson disorder model. A systematic expansion in orthogonal vector spherical harmonics is used for the angular depe...
1908.02680v2
2019-08-16
Dynamics of Hot Bose-Einstein Condensates: stochastic Ehrenfest relations for number and energy damping
Describing partially-condensed Bose gases poses a long-standing theoretical challenge. We present exact stochastic Ehrenfest relations for the stochastic projected Gross-Pitaevskii equation, including both number and energy damping mechanisms, and all projector terms that arise from the energy cutoff separating system ...
1908.05809v3
2019-08-12
On a simple derivation of the very low damping escape rate for classical spins by modifying the method of Kramers
The original perturbative Kramers' method (starting from the phase space coordinates) (Kramers, 1940) of determining the energy-controlled-diffusion equation for Newtonian particles with separable and additive Hamiltonians is generalized to yield the energy-controlled diffusion equation and thus the very low damping (V...
1908.06747v1
2019-08-22
Improving the dynamics of quantum sensors with reinforcement learning
Recently proposed quantum-chaotic sensors achieve quantum enhancements in measurement precision by applying nonlinear control pulses to the dynamics of the quantum sensor while using classical initial states that are easy to prepare. Here, we use the cross-entropy method of reinforcement learning to optimize the streng...
1908.08416v2
2019-08-28
Spin functional renormalization group for quantum Heisenberg ferromagnets: Magnetization and magnon damping in two dimensions
We use the spin functional renormalization group recently developed by two of us [J. Krieg and P. Kopietz, Phys. Rev. B $\bf{99}$, 060403(R) (2019)] to calculate the magnetization $M ( H , T )$ and the damping of magnons due to classical longitudinal fluctuations of quantum Heisenberg ferromagnets. In order to guarante...
1908.10753v2
2019-09-03
Learning Elastic Constitutive Material and Damping Models
Commonly used linear and nonlinear constitutive material models in deformation simulation contain many simplifications and only cover a tiny part of possible material behavior. In this work we propose a framework for learning customized models of deformable materials from example surface trajectories. The key idea is t...
1909.01875v2
2019-09-06
Effect of Tantalum spacer thickness and deposition conditions on the properties of MgO/CoFeB/Ta/CoFeB/MgO free layers
To get stable perpendicularly magnetized tunnel junctions at small device dimensions, composite free layers that comprise two MgO/FeCoB interfaces as sources of interface anisotropy are generally used. Proper cristallisation and annealing robustness is typically ensured by the insertion of a spacer layer of the early t...
1909.02741v1
2019-09-10
Spin Pumping from Permalloy into Uncompensated Antiferromagnetic Co doped Zinc Oxide
Heterostructures of Co-doped ZnO and Permalloy were investigated for their static and dynamic magnetic interaction. The highly Co-doped ZnO is paramagentic at room temperature and becomes an uncompensated antiferromagnet at low temperatures, showing a narrowly opened hysteresis and a vertical exchange bias shift even i...
1909.04362v3
2019-09-19
Blow-up for Strauss type wave equation with damping and potential
We study a kind of nonlinear wave equations with damping and potential, whose coefficients are both critical in the sense of the scaling and depend only on the spatial variables. Based on the earlier works, one may think there are two kinds of blow-up phenomenons when the exponent of the nonlinear term is small. It als...
1909.08885v3
2019-09-23
Inference of modes for linear stochastic processes
For dynamical systems that can be modelled as asymptotically stable linear systems forced by Gaussian noise, this paper develops methods to infer or estimate their modes from observations in real time. The modes can be real or complex. For a real mode, we wish to infer its damping rate and mode shape. For a complex mod...
1909.10247v2
2019-11-06
High spin mixing conductance and spin interface transparency at $Co_2Fe_{0.4}Mn_{0.6}Si$ Heusler alloy and Pt interface
Ferromagnetic materials exhibiting low magnetic damping ($\alpha$) and moderately high saturation magnetization are required from the viewpoints of generation, transmission and detection of spin wave. Since spin-to-charge conversion efficiency is another important parameter, high spin mixing conductance ($g_{r}^{\uparr...
1911.02230v1
2019-11-10
Influence of resonances on the noise performance of SQUID susceptometers
Scanning Superconducting Quantum Interference Device (SQUID) Susceptometry simultaneously images the local magnetic fields and susceptibilities above a sample with sub-micron spatial resolution. Further development of this technique requires a thorough understanding of the current, voltage, and flux characteristics of ...
1911.03836v2
2019-11-13
Impact of the crystal orientation on spin-orbit torques in Fe/Pd bilayers
Spin-orbit torques in ferromagnetic (FM)/non-magnetic (NM) heterostructures offer more energy-efficient means to realize spin-logic devices; however, their strengths are determined by the heterostructure interface. This work examines crystal orientation impact on the spin-orbit torque efficiency in different Fe/Pd bila...
1911.05487v1
2020-01-04
Finite Difference/Galerkin Finite Element Simulation of the Semi-Linear Wave Equation with Scale-Invariant Damping and Mass and Power Non-Linearity
This study is concern with the numerical solution of the initial boundary value problem (IBVP) for the semilinear scale-invariant wave equation with damping and mass and power non-linearity. Numerical results of the aforementioned IBVP is obtained by using standart Galerkin finite element method (GFEM) for the spatial ...
2001.01075v2
2020-01-05
Quantifying quantum non-Markovianity based on quantum coherence via skew information
Based on the nonincreasing property of quantum coherence via skew information under incoherent completely positive and trace-preserving maps, we propose a non-Markovianity measure for open quantum processes. As applications, by applying the proposed measure to some typical noisy channels, we find that it is equivalent ...
2001.01261v1
2020-01-07
von Neumann entropy and the entropy production of a damped harmonic oscillator
In this paper we analyze the entropy and entropy production of a non-isolated quantum system described within the quantum Brownian motion framework. This is a very general and paradigmatic framework for describing non-isolated quantum systems and can be used in any kind of coupling regime. We start by considering the a...
2001.02261v1