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2015-10-23 | Laser-induced THz magnetization precession for a tetragonal Heusler-like nearly compensated ferrimagnet | Laser-induced magnetization precessional dynamics was investigated in
epitaxial films of Mn$_3$Ge, which is a tetragonal Heusler-like nearly
compensated ferrimagnet. The ferromagnetic resonance (FMR) mode was observed,
the precession frequency for which exceeded 0.5 THz and originated from the
large magnetic anisotropy... | 1510.06793v1 |
2017-04-11 | CoFeAlB alloy with low damping and low magnetization for spin transfer torque switching | We investigate the effect of Al doping on the magnetic properties of the
alloy CoFeB. Comparative measurements of the saturation magnetization, the
Gilbert damping parameter $\alpha$ and the exchange constant as a function of
the annealing temperature for CoFeB and CoFeAlB thin films are presented. Our
results reveal a... | 1704.03326v1 |
2017-05-10 | Negative mobility of a Brownian particle: strong damping regime | We study impact of inertia on directed transport of a Brownian particle under
non-equilibrium conditions: the particle moves in a one-dimensional periodic
and symmetric potential, is driven by both an unbiased time-periodic force and
a constant force, and is coupled to a thermostat of temperature T. Within
selected par... | 1705.03661v1 |
2018-04-09 | Damping and clustering into crowded environment of catalytic chemical oscillators | A system formed by a crowded environment of catalytic obstacles and complex
oscillatory chemical reactions is inquired. The obstacles are static spheres of
equal radius, which are placed in a random way. The chemical reactions are
carried out in a fluid following a multiparticle collision scheme where the
mass, energy ... | 1804.03174v1 |
2018-10-09 | The lifespan of solutions of semilinear wave equations with the scale-invariant damping in one space dimension | The critical constant of time-decaying damping in the scale-invariant case is
recently conjectured. It also has been expected that the lifespan estimate is
the same as for the associated semilinear heat equations if the constant is in
the \heat-like" domain. In this paper, we point out that this is not true if
the tota... | 1810.03780v2 |
2019-04-23 | Ultrafast depinning of domain wall in notched antiferromagnetic nanostructures | The pinning and depinning of antiferromagnetic (AFM) domain wall is certainly
the core issue of AFM spintronics. In this work, we study theoretically the
N\'eel-type domain wall pinning and depinning at a notch in an
antiferromagnetic (AFM) nano-ribbon. The depinning field depending on the notch
dimension and intrinsic... | 1904.10197v2 |
2019-08-30 | Magnetization reversal, damping properties and magnetic anisotropy of L10-ordered FeNi thin films | L10 ordered magnetic alloys such as FePt, FePd, CoPt and FeNi are well known
for their large magnetocrystalline anisotropy. Among these, L10-FeNi alloy is
economically viable material for magnetic recording media because it does not
contain rare earth and noble elements. In this work, L10-FeNi films with three
differen... | 1908.11761v1 |
2004-09-10 | Constraint on the Squeeze Parameter of Inflaton from Cosmological Constant | The inflaton is highly likely to settle in a squeezed vacuum state after
inflation. The relic inflaton after inflation and reheating undergoes a damped
oscillatory motion and contributes to the effective cosmological constant. We
interpret the renormalized energy density from the squeezed vacuum state as an
effective c... | 0409044v1 |
2007-02-12 | The Ucsd/Keck Damped Lya Abundance Database: A Decade of High Resolution Spectroscopy | We publish the Keck/HIRES and Keck/ESI spectra that we have obtained during
the first 10 years of Keck observatory operations. Our full sample includes 42
HIRES spectra and 39 ESI spectra along 65 unique sightlines providing abundance
measurements on ~85 damped Lya systems. The normalized data can be downloaded
from th... | 0702325v1 |
1998-06-30 | Structure and Spin Dynamics of La$_{0.85}$Sr$_{0.15}$MnO$_3$ | Neutron scattering has been used to study the structure and spin dynamics of
La$_{0.85}$Sr$_{0.15}$MnO$_3$. The magnetic structure of this system is
ferromagnetic below T_C = 235 K. We see anomalies in the Bragg peak intensities
and new superlattice peaks consistent with the onset of a spin-canted phase
below T_{CA} = ... | 9806381v1 |
2008-02-11 | Eccentricity of masing disks in Active Galactic Nuclei | Observations of Keplerian disks of masers in NCG 4258 and other Seyfert
galaxies can be used to obtain geometric distance estimates and derive the
Hubble constant. The ultimate precision of such measurements could be limited
by uncertainties in the disk geometry. Using a time-dependent linear theory
model, we study the... | 0802.1524v1 |
2013-09-26 | Non-Landau damping of magnetic excitations in systems with localized and itinerant electrons | We discuss the form of the damping of magnetic excitations in a metal near a
ferromagnetic instability. The paramagnon theory predicts that the damping term
should have the form $\Omega/\Gamma (q)$ with $\Gamma (q) \propto q$ (the
Landau damping). However, the experiments on uranium metallic compounds UGe$_2$
and UCoGe... | 1309.7065v3 |
2016-04-20 | Nonlinear wave damping due to multi-plasmon resonances | For short wavelengths, it is well known that the linearized Wigner-Moyal
equation predicts wave damping due to wave-particle interaction, where the
resonant velocity shifted from the phase velocity by a velocity $v_q = \hbar
k/2m$. Here $\hbar$ is the reduced Planck constant, $k$ is the wavenumber and
$m$ is the electr... | 1604.05983v2 |
2017-10-30 | Enhancement of intrinsic magnetic damping in defect-free epitaxial Fe3O4 thin films | We have investigated the magnetic damping of precessional spin dynamics in
defect-controlled epitaxial grown Fe$_3$O$_4$(111)/Yttria-stabilized Zirconia
(YSZ) nanoscale films by all-optical pump-probe measurements. The intrinsic
damping constant of the defect-free Fe$_3$O$_4$ film is found to be strikingly
larger than ... | 1710.10938v2 |
2017-11-20 | Spin Pumping in Ion-beam Sputtered Co_{2}FeAl/Mo Bilayers:Interfacial Gilbert Damping | The spin pumping mechanism and associated interfacial Gilbert damping are
demonstrated in ion-beam sputtered Co2FeAl (CFA) /Mo bilayer thin films
employing ferromagnetic resonance spectroscopy. The dependence of the net spin
current transportation on Mo layer thickness, 0 to 10 nm, and the enhancement
of the net effect... | 1711.07455v1 |
2018-07-20 | Another view on Gilbert damping in two-dimensional ferromagnets | A keen interest towards technological implications of spin-orbit driven
magnetization dynamics requests a proper theoretical description, especially in
the context of a microscopic framework, to be developed. Indeed, magnetization
dynamics is so far approached within Landau-Lifshitz-Gilbert equation which
characterizes... | 1807.07897v2 |
2022-06-08 | Motion control with optimal nonlinear damping: from theory to experiment | Optimal nonlinear damping control was recently introduced for the
second-order SISO systems, showing some advantages over a classical PD feedback
controller. This paper summarizes the main theoretical developments and
properties of the optimal nonlinear damping controller and demonstrates, for
the first time, its pract... | 2206.03802v2 |
2023-07-12 | Exponential stability of damped Euler-Bernoulli beam controlled by boundary springs and dampers | In this paper, the vibration model of an elastic beam, governed by the damped
Euler-Bernoulli equation
$\rho(x)u_{tt}+\mu(x)u_{t}$$+\left(r(x)u_{xx}\right)_{xx}=0$, subject to the
clamped boundary conditions $u(0,t)=u_x(0,t)=0$ at $x=0$, and the boundary
conditions $\left(-r(x)u_{xx}\right)_{x=\ell}=k_r u_x(\ell,t)+k_a... | 2307.06170v2 |
2000-09-06 | The Cosmological Evolution of Quasar Damped Lyman-Alpha Systems | We present results from an efficient, non-traditional survey to discover
damped Lyman-alpha (DLA) absorption-line systems with neutral hydrogen column
densities N(HI)>2x10^{20} atoms cm^{-2} and redshifts z<1.65. Contrary to
previous studies at higher redshift that showed a decrease in the cosmological
mass density of ... | 0009098v1 |
2005-06-09 | Phantom damping of matter perturbations | Cosmological scaling solutions are particularly important in solving the
coincidence problem of dark energy. We derive the equations of sub-Hubble
linear matter perturbations for a general scalar-field Lagrangian--including
quintessence, tachyon, dilatonic ghost condensate and k-essence--and solve them
analytically for... | 0506222v1 |
1995-02-10 | The influence of structure disorder on mean atomic momentum fluctuations and a spin-wave spectrum | The relation between atomic momenta fluctuations and density fluctuations is
obtained in frames of mean-field approximation. Using two-time temperature
Green functions within Tyablikov approximation the equations for spin
excitation energy and damping are obtained. The asymptotics of energy and
damping in the long-wave... | 9502042v1 |
1999-01-19 | Damping of Growth Oscillations | Computer simulations and scaling theory are used to investigate the damping
of oscillations during epitaxial growth on high-symmetry surfaces. The
crossover from smooth to rough growth takes place after the deposition of
(D/F)^\delta monolayers, where D and F are the surface diffusion constant and
the deposition rate, ... | 9901178v1 |
2000-03-27 | Effect of memory and dynamical chaos in long Josephson junctions | A long Josephson junction in a constant external magnetic field and in the
presence of a dc bias current is investigated. It is shown that the system,
simulated by the sine-Gorgon equation, "remembers" a rapidly damping initial
perturbation and final asymptotic states are determined exactly with this
perturbation. Nume... | 0003421v1 |
2003-09-24 | Landau Damping in a 2D Electron Gas with Imposed Quantum Grid | Dielectric properties of semiconductor substrate with imposed two dimensional
(2D) periodic grid of quantum wires or nanotubes (quantum crossbars, QCB) are
studied. It is shown that a capacitive contact between QCB and semiconductor
substrate does not destroy the Luttinger liquid character of the long wave QCB
excitati... | 0309546v2 |
2005-11-05 | Ratchet Effect in Magnetization Reversal of Stoner Particles | A new strategy is proposed aimed at substantially reducing the minimal
magnetization switching field for a Stoner particle. Unlike the normal method
of applying a static magnetic field which must be larger than the magnetic
anisotropy, a much weaker field, proportional to the damping constant in the
weak damping regime... | 0511135v1 |
1994-09-12 | Fermion damping rate in a hot medium | In principle every excitation acquires a finite lifetime in a hot system.
This nonzero spectral width is calculated self-consistently for massive
fermions coupled to massless scalar, vector and pseudoscalar bosons. It is
shown that the self-consistent summation of the corresponding Fock diagram for
fermions eliminates ... | 9409280v2 |
2004-02-06 | Critical Behavior of Damping Rate for Plasmon with Finite Momentum in φ^4 Theory | Applying thermal renormalization group (TRG) equations to $\phi^4$ theory
with spontaneous breaking symmetry, we investigate the critical behavior of the
damping rate for the plasmons with finite momentum at the symmetry-restoring
phase transition. From the TRG equation the IR cutoff provided by the external
momentum l... | 0402069v2 |
2006-11-26 | On the Lagrangian and Hamiltonian description of the damped linear harmonic oscillator | Using the modified Prelle- Singer approach, we point out that explicit time
independent first integrals can be identified for the damped linear harmonic
oscillator in different parameter regimes. Using these constants of motion, an
appropriate Lagrangian and Hamiltonian formalism is developed and the resultant
canonica... | 0611048v1 |
2005-02-10 | Modulational instabilities in Josephson oscillations of elongated coupled condensates | We study the Josephson oscillations of two coupled elongated condensates.
Linearized calculations show that the oscillating mode uniform over the length
of the condensates (uniform Josephson mode) is unstable : modes of non zero
longitudinal momentum grow exponentially. In the limit of strong atom
interactions, we give... | 0502050v3 |
2007-10-04 | Activation of additional energy dissipation processes in the magnetization dynamics of epitaxial chromium dioxide films | The precessional magnetization dynamics of a chromium dioxide$(100)$ film is
examined in an all-optical pump-probe setup. The frequency dependence on the
external field is used to extract the uniaxial in-plane anisotropy constant.
The damping shows a strong dependence on the frequency, but also on the laser
pump fluenc... | 0710.0986v2 |
2009-02-03 | Freezing of spin dynamics in underdoped cuprates | The Mori's memory function approach to spin dynamics in doped
antiferromagnetic insulator combined with the assumption of temperature
independent static spin correlations and constant collective mode damping leads
to w/T scaling in a broad range. The theory involving a nonuniversal scaling
parameter is used to analyze ... | 0902.0546v1 |
2010-04-26 | Entanglement of a two-particle Gaussian state interacting with a heat bath | The effect of a thermal reservoir is investigated on a bipartite Gaussian
state. We derive a pre-Lindblad master equation in the non-rotating wave
approximation for the system. We then solve the master equation for a bipartite
harmonic oscillator Hamiltonian with entangled initial state. We show that for
strong damping... | 1004.4515v2 |
2011-04-06 | Relativistic magnetic reconnection at X-type neutral points | Relativistic effects in the oscillatory damping of magnetic disturbances near
two-dimensional X-points are investigated. By taking into account displacement
current, we study new features of extremely magnetized systems, in which the
Alfv\'en velocity is almost the speed of light. The frequencies of the
least-damped mo... | 1104.1003v1 |
2011-11-08 | The entropy of large black holes in loop quantum gravity: A combinatorics/analysis approach | The issue of a possible damping of the entropy periodicity for large black
holes in Loop Quantum Gravity is highly debated. Using a combinatorics/analysis
approach, we give strong arguments in favor of this damping, at least for
prescriptions where the projection constraint is not fully implemented. This
means that bla... | 1111.1975v1 |
2013-04-04 | Pais-Uhlenbeck Oscillator with a Benign Friction Force | It is shown that the Pais-Uhlenbeck oscillator with damping, considered by
Nesterenko, is a special case of a more general oscillator that has not only a
first order, but also a third order friction term. If the corresponding damping
constants, \alpha\ and \beta, are both positive and below certain critical
values, the... | 1304.1325v2 |
2014-12-05 | Exponential dephasing of oscillators in the Kinetic Kuramoto Model | We study the kinetic Kuramoto model for coupled oscillators with coupling
constant below the synchronization threshold. We manage to prove that, for any
analytic initial datum, if the interaction is small enough, the order parameter
of the model vanishes exponentially fast, and the solution is asymptotically
described ... | 1412.1923v1 |
2014-12-23 | Selftrapping triggered by losses in cavity QED | In a coupled cavity QED network model, we study the transition from a
localized super fluid like state to a delocalized Mott insulator like state,
triggered by losses. Without cavity losses, the transition never takes place.
Further, if one measures the quantum correlations between the polaritons via
the negativity, we... | 1412.7495v1 |
2015-11-19 | Periodic damping gives polynomial energy decay | Let $u$ solve the damped Klein--Gordon equation $$ \big( \partial_t^2-\sum
\partial_{x_j}^2 +m \text{Id} +\gamma(x) \partial_t \big) u=0 $$ on
$\mathbb{R}^n$ with $m>0$ and $\gamma\geq 0$ bounded below on a $2 \pi
\mathbb{Z}^n$-invariant open set by a positive constant. We show that the
energy of the solution $u$ decay... | 1511.06144v5 |
2016-06-08 | Energy Decay in a Wave Guide with Dissipation at Infinity | We prove local and global energy decay for the wave equation in a wave guide
with damping at infinity. More precisely, the absorption index is assumed to
converge slowly to a positive constant, and we obtain the diffusive phenomenon
typical for the contribution of low frequencies when the damping is effective
at infini... | 1606.02549v2 |
2016-07-06 | Asymptotic profiles of solutions for structural damped wave equations | In this paper, we obtain several asymptotic profiles of solutions to the
Cauchy problem for structurally damped wave equations $\partial_{t}^{2} u -
\Delta u + \nu (-\Delta)^{\sigma} \partial_{t} u=0$, where $\nu >0$ and $0<
\sigma \le1$. Our result is the approximation formula of the solution by a
constant multiple of... | 1607.01839v1 |
2018-01-19 | Robust integral action of port-Hamiltonian systems | Interconnection and damping assignment, passivity-based control (IDA-PBC) has
proven to be a successful control technique for the stabilisation of many
nonlinear systems. In this paper, we propose a method to robustify a system
which has been stabilised using IDA-PBC with respect to constant, matched
disturbances via t... | 1801.06279v1 |
2018-04-10 | Motion of a superconducting loop in an inhomogeneous magnetic field: a didactic experiment | We present an experiment conductive to an understanding of both Faraday's law
and the properties of the superconducting state. It consists in the analysis of
the motion of a superconducting loop moving under the influence of gravity in
an inhomogeneous horizontal magnetic field. Gravity, conservation of magnetic
flux, ... | 1804.03553v1 |
2019-09-11 | Remark on global existence of solutions to the 1D compressible Euler equation with time-dependent damping | In this paper, we consider the 1D compressible Euler equation with the
damping coefficient $\lambda/(1+t)^{\mu}$. Under the assumption that $0\leq \mu
<1$ and $\lambda >0$ or $\mu=1$ and $\lambda > 2$, we prove that solutions
exist globally in time, if initial data are small $C^1$ perturbation near
constant states. In ... | 1909.05683v1 |
2020-10-18 | Classical limit of quantum mechanics for damped driven oscillatory systems: Quantum-classical correspondence | The investigation of quantum-classical correspondence may lead to gain a
deeper understanding of the classical limit of quantum theory. We develop a
quantum formalism on the basis of a linear-invariant theorem, which gives an
exact quantum-classical correspondence for damped oscillatory systems that are
perturbed by an... | 2010.08971v1 |
2020-12-28 | An efficient method for approximating resonance curves of weakly-damped nonlinear mechanical systems | A method is presented for tracing the locus of a specific peak in the
frequency response under variation of a parameter. It is applicable to
periodic, steady-state vibrations of harmonically forced nonlinear mechanical
systems. It operates in the frequency domain and its central idea is to assume
a constant phase lag b... | 2012.14458v1 |
2021-02-04 | Global existence results for semi-linear structurally damped wave equations with nonlinear convection | In this paper, we consider the Cauchy problem for semi-linear wave equations
with structural damping term $\nu (-\Delta)^2 u_t$, where $\nu >0$ is a
constant. As being mentioned in [8,10], the linear principal part brings both
the diffusion phenomenon and the regularity loss of solutions. This implies
that, for the non... | 2102.02445v2 |
2021-04-12 | The pressureless damped Euler-Riesz equations | In this paper, we analyze the pressureless damped Euler-Riesz equations posed
in either $\mathbb{R}^d$ or $\mathbb{T}^d$. We construct the global-in-time
existence and uniqueness of classical solutions for the system around a
constant background state. We also establish large-time behaviors of classical
solutions showi... | 2104.05153v1 |
2021-05-20 | On the the critical exponent for the semilinear Euler-Poisson-Darboux-Tricomi equation with power nonlinearity | In this note, we derive a blow-up result for a semilinear generalized Tricomi
equation with damping and mass terms having time-dependent coefficients. We
consider these coefficients with critical decay rates. Due to this threshold
nature of the time-dependent coefficients (both for the damping and for the
mass), the mu... | 2105.09879v2 |
2022-04-04 | Exponential ergodicity for damping Hamiltonian dynamics with state-dependent and non-local collisions | In this paper, we investigate the exponential ergodicity in a
Wasserstein-type distance for a damping Hamiltonian dynamics with
state-dependent and non-local collisions, which indeed is a special case of
piecewise deterministic Markov processes while is very popular in numerous
modelling situations including stochastic... | 2204.01372v1 |
2022-06-17 | On energy-stable and high order finite element methods for the wave equation in heterogeneous media with perfectly matched layers | This paper presents a stable finite element approximation for the acoustic
wave equation on second-order form, with perfectly matched layers (PML) at the
boundaries. Energy estimates are derived for varying PML damping for both the
discrete and the continuous case. Moreover, a priori error estimates are
derived for con... | 2206.08507v1 |
2022-12-27 | Stabilization of the Kawahara-Kadomtsev-Petviashvili equation with time-delayed feedback | Results of stabilization for the higher order of the Kadomtsev-Petviashvili
equation are presented in this manuscript. Precisely, we prove with two
different approaches that under the presence of a damping mechanism and an
internal delay term (anti-damping) the solutions of the
Kawahara-Kadomtsev-Petviashvili equation ... | 2212.13552v1 |
2014-10-20 | Frequency-dependent attenuation and elasticity in unconsolidated earth materials: effect of damping | We use the Discrete Element Method (DEM) to understand the underlying
attenuation mechanism in granular media, with special applicability to the
measurements of the so-called effective mass developed earlier. We consider
that the particles interact via Hertz-Mindlin elastic contact forces and that
the damping is descri... | 1410.5484v2 |
2018-09-13 | Active Damping of a DC Network with a Constant Power Load: An Adaptive Passivity-based Control Approach | This paper proposes a nonlinear, adaptive controller to increase the
stability margin of a direct-current (DC) small-scale electrical network
containing a constant power load, whose value is unknown. Due to their negative
incremental impedance, constant power loads are known to reduce the effective
damping of a network... | 1809.04920v1 |
2018-10-29 | A Graceful Exit for the Cosmological Constant Damping Scenario | We present a broad and simple class of scalar-tensor scenarios that
successfully realize dynamical damping of the effective cosmological constant,
therefore providing a viable dynamical solution to the fine-tuning or "old"
cosmological constant problem. In contrast to early versions of this approach,
pioneered in the w... | 1810.12336v2 |
2020-10-01 | Avoiding coherent errors with rotated concatenated stabilizer codes | Coherent errors, which arise from collective couplings, are a dominant form
of noise in many realistic quantum systems, and are more damaging than oft
considered stochastic errors. Here, we propose integrating stabilizer codes
with constant-excitation codes by code concatenation. Namely, by concatenating
an $[[n,k,d]]$... | 2010.00538v2 |
2023-05-17 | Material Parameters for Faster Ballistic Switching of an In-plane Magnetized Nanomagnet | High-speed magnetization switching of a nanomagnet is necessary for faster
information processing. The ballistic switching by a pulsed magnetic filed is a
promising candidate for the high-speed switching. It is known that the
switching speed of the ballistic switching can be increased by increasing the
magnitude of the... | 2305.10111v1 |
1995-05-17 | GRAVITATIONAL LENSING OF QUASARS BY THEIR DAMPED LYMAN-ALPHA ABSORBERS | Damped Lyman-alpha absorbers are believed to be associated with galactic
disks. We show that gravitational lensing can therefore affect the statistics
of these systems. First, the magnification bias due to lensing raises faint
QSOs above a given magnitude threshold and thereby enhances the probability for
observing dam... | 9505078v1 |
2000-06-01 | Crust-core coupling and r-mode damping in neutron stars: a toy model | R-modes in neutron stars with crusts are damped by viscous friction at the
crust-core boundary. The magnitude of this damping, evaluated by Bildsten and
Ushomirsky (BU) under the assumption of a perfectly rigid crust, sets the
maximum spin frequency for a neutron star spun up by accretion in a Low-Mass
X-ray binary (LM... | 0006028v1 |
2006-06-15 | Purity and decoherence in the theory of a damped harmonic oscillator | For the generalized master equations derived by Karrlein and Grabert for the
microscopic model of a damped harmonic oscillator, the conditions for purity of
states are written, in particular for different initial conditions and
different types of damping, including Ohmic, Drude and weak coupling cases,
Agarwal and Weid... | 0606134v1 |
2012-10-02 | Coherence and Stimulated Emission in the Tavis-Cummings Model: A Quantum Description of the Free Induction Signal and Radiation Damping in Magnetic Resonance | We numerically solve the Liouville equation for the Tavis Cummings model of
multiple spins coupled to a lossless single mode cavity, starting from an
initial condition with small numbers of fully polarized spins tipped by a
specified angle, and the cavity in its ground Fock state. Time evolution of the
magnetizations a... | 1210.0868v2 |
2016-11-28 | First Demonstration of Electrostatic Damping of Parametric Instability at Advanced LIGO | Interferometric gravitational wave detectors operate with high optical power
in their arms in order to achieve high shot-noise limited strain sensitivity. A
significant limitation to increasing the optical power is the phenomenon of
three-mode parametric instabilities, in which the laser field in the arm
cavities is sc... | 1611.08997v1 |
2021-07-28 | Evolution of a Mode of Oscillation Within Turbulent Accretion Disks | We investigate the effects of subsonic turbulence on a normal mode of
oscillation [a possible origin of the high-frequency quasi-periodic
oscillations (HFQPOs) within some black hole accretion disks]. We consider
perturbations of a time-dependent background (steady state disk plus
turbulence), obtaining an oscillator e... | 2107.13546v1 |
2001-02-06 | Decay of cosmological constant as Bose condensate evaporation | We consider the process of decay of symmetric vacuum state as evaporation of
a Bose condensate of physical Higgs particles, defined over asymmetric vacuum
state. Energy density of their selfinteraction is identified with cosmological
constant $\Lambda$ in the Einstein equation. $\Lambda$ decay then provides
dynamical r... | 0102094v2 |
2003-07-12 | Time-variability of the fine-structure constant expected from the Oklo constraint and the QSO absorption lines | The data from the QSO absorption lines indicating a nonzero time-variability
of the fine-structure constant has been re-analyzed on the basis of a
"damped-oscillator" fit, as motivated by the same type of behavior of a scalar
field, dilaton, which mimics a cosmological constant to understand the
accelerating universe. ... | 0307263v2 |
1996-01-30 | Role of a "Local" Cosmological Constant in Euclidean Quantum Gravity | In 4D non-perturbative Regge calculus a positive value of the effective
cosmological constant characterizes the collapsed phase of the system. If a
local term of the form $S'=\sum_{h \epsilon \{h_1,h_2,...\} } \lambda_h V_h$ is
added to the gravitational action, where $\{h_1,h_2,...\}$ is a subset of the
hinges and $\{... | 9601160v1 |
1999-07-12 | General considerations of the cosmological constant and the stabilization of moduli in the brane-world picture | We argue that the brane-world picture with matter-fields confined to 4-d
domain walls and with gravitational interactions across the bulk disallows
adding an arbitrary constant to the low-energy, 4-d effective theory -- which
finesses the usual cosmological constant problem. The analysis also points to
difficulties in ... | 9907080v1 |
2007-06-03 | A class of series acceleration formulae for Catalan's constant | In this note, we develop transformation formulae and expansions for the log
tangent integral, which are then used to derive series acceleration formulae
for certain values of Dirichlet L-functions, such as Catalan's constant. The
formulae are characterized by the presence of an infinite series whose general
term consis... | 0706.0356v1 |
2017-09-21 | Low Gilbert Damping Constant in Perpendicularly Magnetized W/CoFeB/MgO Films with High Thermal Stability | Perpendicular magnetic materials with low damping constant and high thermal
stability have great potential for realizing high-density, non-volatile, and
low-power consumption spintronic devices, which can sustain operation
reliability for high processing temperatures. In this work, we study the
Gilbert damping constant... | 1709.07483v1 |
2022-09-21 | Performance enhancement of a spin-wave-based reservoir computing system utilizing different physical conditions | The authors have numerically studied how to enhance reservoir computing
performance by thoroughly extracting their spin-wave device potential for
higher-dimensional information generation. The reservoir device has a 1-input
exciter and 120-output detectors on the top of a continuous magnetic garnet
film for spin-wave t... | 2209.10123v1 |
2000-06-09 | Random values of the cosmological constant | One way that an anthropic selection mechanism may be manifest in a physical
theory involves multiple domains in the universe with different values of the
physical parameters. If this mechanism is to be relevant for understanding the
small observed value of the cosmological constant, it may involve a mechanism
by which ... | 0006088v2 |
2013-05-11 | Dividing Line between Quantum and Classical Trajectories: Bohmian Time Constant | This work proposes an answer to a challenge posed by Bell on the lack of
clarity in regards to the line between the quantum and classical regimes in a
measurement problem. To this end, a generalized logarithmic nonlinear
Schr\"odinger equation is proposed to describe the time evolution of a quantum
dissipative system u... | 1305.2517v2 |
2014-08-20 | Building accurate initial models using gain functions for waveform inversion in the Laplace domain | We suggest an initial model building technique using time gain functions in
the Laplace domain. Applying the gain expressed as a power of time is
equivalent to taking the partial derivative of the Laplace-domain wavefield
with respect to a damping constant. We construct an objective function, which
minimizes the logari... | 1408.5872v1 |
1995-10-16 | Star Formation and Chemical Evolution in Damped Lya Clouds | Using the redshift evolution of the neutral hydrogen density, as inferred
from observations of damped Ly$\alpha$ clouds, we calculate the evolution of
star formation rates and elemental abundances in the universe. For most
observables our calculations are in rough agreement with previous results based
on the instantane... | 9510078v1 |
2003-03-27 | Oscillatory wave fronts in chains of coupled nonlinear oscillators | Wave front pinning and propagation in damped chains of coupled oscillators
are studied. There are two important thresholds for an applied constant stress
$F$: for $|F|<F_{cd}$ (dynamic Peierls stress), wave fronts fail to propagate,
for $F_{cd} < |F| < F_{cs}$ stable static and moving wave fronts coexist, and
for $|F| ... | 0303576v1 |
2003-07-22 | Classical dynamics of a nano-mechanical resonator coupled to a single-electron transistor | We analyze the dynamics of a nano-mechanical resonator coupled to a
single-electron transistor (SET) in the regime where the resonator behaves
classically. A master equation is derived describing the dynamics of the
coupled system which is then used to obtain equations of motion for the average
charge state of the SET ... | 0307528v1 |
2006-05-16 | Collective mode damping and viscosity in a 1D unitary Fermi gas | We calculate the damping of the Bogoliubov-Anderson mode in a one-dimensional
two-component attractive Fermi gas for arbitrary coupling strength within a
quantum hydrodynamic approach. Using the Bethe-Ansatz solution of the 1D
BCS-BEC crossover problem, we derive analytic results for the viscosity
covering the full ran... | 0605413v2 |
2006-06-09 | Spin wave dynamics and the determination of intrinsic Gilbert damping in locally-excited Permalloy thin films | Time-resolved scanning Kerr effect microscopy has been used to study
magnetization dynamics in Permalloy thin films excited by transient magnetic
pulses generated by a micrometer-scale transmission line structure. The results
are consistent with magnetostatic spin wave theory and are supported by
micromagnetic simulati... | 0606235v3 |
1996-03-14 | Dissipation and Topologically Massive Gauge Theories in Pseudoeuclidean Plane | In the pseudo-euclidean metrics Chern-Simons gauge theory in the infrared
region is found to be associated with dissipative dynamics. In the infrared
limit the Lagrangian of 2+1 dimensional pseudo-euclidean topologically massive
electrodynamics has indeed the same form of the Lagrangian of the damped
harmonic oscillato... | 9603092v1 |
2002-02-12 | Landau Damping and Coherent Structures in Narrow-Banded 1+1 Deep Water Gravity Waves | We study the nonlinear energy transfer around the peak of the spectrum of
surface gravity waves by taking into account nonhomogeneous effects. In the
narrow-banded approximation the kinetic equation resulting from a
nonhomogeneous wave field is a Vlasov-Poisson type equation which includes at
the same time the random v... | 0202026v1 |
2006-07-31 | Nonadiabatic Transitions for a Decaying Two-Level-System: Geometrical and Dynamical Contributions | We study the Landau-Zener Problem for a decaying two-level-system described
by a non-hermitean Hamiltonian, depending analytically on time. Use of a
super-adiabatic basis allows to calculate the non-adiabatic transition
probability P in the slow-sweep limit, without specifying the Hamiltonian
explicitly. It is found th... | 0607221v1 |
2007-06-01 | The geometrical quantity in damped wave equations on a square | The energy in a square membrane $\Omega$ subject to constant viscous damping
on a subset $\omega\subset \Omega$ decays exponentially in time as soon as
$\omega$ satisfies a geometrical condition known as the "Bardos-Lebeau-Rauch"
condition. The rate $\tau(\omega)$ of this decay satisfies $\tau(\omega)= 2
\min(-\mu(\ome... | 0706.0172v1 |
2009-10-14 | Constraint on the growth factor of the cosmic structure from the damping of the baryon acoustic oscillation signature | We determine a constraint on the growth factor by measuring the damping of
the baryon acoustic oscillations in the matter power spectrum using the Sloan
Digital Sky Survey luminous red galaxy sample. The damping of the BAO is
detected at the one sigma level. We obtain \sigma_8D_1(z=0.3) =
0.42^{+0.34}_{-0.28} at the 1\... | 0910.2513v1 |
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 |
2011-03-08 | 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 |
2011-06-17 | 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 |
2011-07-24 | 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 |
2011-12-02 | 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 |
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 |
2015-02-05 | Nonlinear analysis of magnetization dynamics excited by spin Hall effect | We investigate the possibility of exciting self-oscillation in a
perpendicular ferromagnet by the spin Hall effect on the basis of a nonlinear
analysis of the Landau-Lifshitz-Gilbert (LLG) equation. In the self-oscillation
state, the energy supplied by the spin torque during a precession on a constant
energy curve shou... | 1502.01420v2 |
2015-04-09 | Periodic-coefficient damping estimates, and stability of large-amplitude roll waves in inclined thin film flow | A technical obstruction preventing the conclusion of nonlinear stability of
large-Froude number roll waves of the St. Venant equations for inclined thin
film flow is the "slope condition" of Johnson-Noble-Zumbrun, used to obtain
pointwise symmetrizability of the linearized equations and thereby
high-frequency resolvent... | 1504.02292v1 |
2015-05-08 | Existence and general stabilization of the Timoshenko system with a thermo-viscoelastic damping and a delay term in the internal feedback | In this paper, we consider a Timoshenko system with a thermo-viscoelastic
damping and a delay term in the internal feedback together with initial datum
and boundary conditions of Dirichlet type, where g is a positive non-increasing
relaxation function and {\mu}1, {\mu}2 are positive constants. Under an
hypothesis betwe... | 1505.01899v1 |
2016-03-25 | Large spin pumping effect in antisymmetric precession of Ni$_{79}$Fe$_{21}$/Ru/Ni$_{79}$Fe$_{21}$ | In magnetic trilayer structures, a contribution to the Gilbert damping of
ferromagnetic resonance arises from spin currents pumped from one layer to
another. This contribution has been demonstrated for layers with weakly
coupled, separated resonances, where magnetization dynamics are excited
predominantly in one layer ... | 1603.07977v1 |
2016-05-26 | Thickness and temperature dependence of the magnetodynamic damping of pulsed laser deposited $\text{La}_{0.7}\text{Sr}_{0.3}\text{MnO}_3$ on (111)-oriented SrTi$\text{O}_3$ | We have investigated the magnetodynamic properties of
$\text{La}_{0.7}\text{Sr}_{0.3}\text{MnO}_3$ (LSMO) films of thickness 10, 15
and 30 nm grown on (111)-oriented SrTi$\text{O}_3$ (STO) substrates by pulsed
laser deposition. Ferromagnetic resonance (FMR) experiments were performed in
the temperature range 100--300 K... | 1605.08195v2 |
2017-03-28 | Singularity formation for the 1D compressible Euler equation with variable damping coefficient | In this paper, we consider some blow-up problems for the 1D Euler equation
with time and space dependent damping. We investigate sufficient conditions on
initial data and the rate of spatial or time-like decay of the coefficient of
damping for the occurrence of the finite time blow-up. In particular, our
sufficient con... | 1703.09821v3 |
2017-08-30 | Convergence to diffusion waves for solutions of Euler equations with time-depending damping on quadrant | This paper is concerned with the asymptotic behavior of the solution to the
Euler equations with time-depending damping on quadrant $(x,t)\in
\mathbb{R}^+\times\mathbb{R}^+$, \begin{equation}\notag \partial_t v
-
\partial_x u=0, \qquad \partial_t u
+
\partial_x p(v)
=\displaystyle
-\frac{\alpha}{(1+t)^\lamb... | 1708.09127v1 |
2017-11-01 | Tunable magnetization relaxation of Fe_{2}Cr_{1-x}Co_{x}Si half-metallic Heusler alloys by band structure engineering | We report a systematic investigation on the magnetization relaxation
properties of iron-based half-metallic Heusler alloy
Fe$_{2}$Cr$_{1-x}$Co_${x}$Si (FCCS) thin films using broadband angular-resolved
ferromagnetic resonance. Band structure engineering through Co doping (x)
demonstrated by first-principles calculation... | 1711.00406v1 |
2018-01-23 | The effect of liquid on the vibrational intensity of a wineglass at steady state resonance | As a liquid is inserted into a wineglass, the natural frequency of the
wineglass decreases. This phenomenon, known as pitch lowering, is well
explained in past papers. However, previous literature have not yet mentioned
that pitch lowering also reduces the resonance intensity of a wineglass. Thus,
this present paper ai... | 1801.07514v5 |
2018-04-11 | A global existence result for a semilinear wave equation with scale-invariant damping and mass in even space dimension | In the present article a semilinear wave equation with scale-invariant
damping and mass is considered. The global (in time) existence of radial
symmetric solutions in even spatial dimension $n$ is proved using weighted
$L^\infty-L^\infty$ estimates, under the assumption that the multiplicative
constants, which appear i... | 1804.03978v1 |
2018-12-21 | Reply to the Comment on "Negative Landau damping in bilayer graphene" | Here we address the concerns of Svintsov and Ryzhii [arXiv:1812.03764] on our
article on negative Landau damping in graphene [Phys. Rev. Lett. 119, 133901
(2017)]. We prove that due to the differences between the kinetic and canonical
momenta, the conductivity of drift-current biased graphene is ruled by a
Galilean tra... | 1812.09103v3 |
2018-12-30 | Smooth, Time-invariant Regulation of Nonholonomic Systems via Energy Pumping-and-Damping | In this paper we propose an energy pumping-and-damping technique to regulate
nonholonomic systems described by kinematic models. The controller design
follows the widely popular interconnection and damping assignment
passivity-based methodology, with the free matrices partially structured. Two
asymptotic regulation obj... | 1812.11538v2 |
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