publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2008-08-03 | Superradiant Instability of Five-Dimensional Rotating Charged AdS Black Holes | We study the instability of small AdS black holes with two independent
rotation parameters in minimal five-dimensional gauged supergravity to massless
scalar perturbations. We analytically solve the Klein-Gordon equation for
low-frequency perturbations in two regions of the spacetime of these black
holes: namely, in th... | 0808.0280v3 |
2008-08-15 | Collective excitations in two-dimensional antiferromagnet in strong magnetic field | We discuss spin-$\frac12$ two-dimensional (2D) Heisenberg antiferromagnet
(AF) on a square lattice at T=0 in strong magnetic field H near its saturation
value $H_c$. A perturbation approach is proposed to obtain spectrum of magnons
with momenta not very close to AF vector in the leading order in small
parameter $(H_c-H... | 0808.2127v3 |
2008-08-26 | Nonlinear regularization techniques for seismic tomography | The effects of several nonlinear regularization techniques are discussed in
the framework of 3D seismic tomography. Traditional, linear, $\ell_2$ penalties
are compared to so-called sparsity promoting $\ell_1$ and $\ell_0$ penalties,
and a total variation penalty. Which of these algorithms is judged optimal
depends on ... | 0808.3472v3 |
2008-09-09 | Process tomography of field damping and measurement of Fock state lifetimes by quantum non-demolition photon counting in a cavity | The relaxation of a quantum field stored in a high-$Q$ superconducting cavity
is monitored by non-resonant Rydberg atoms. The field, subjected to repetitive
quantum non-demolition (QND) photon counting, undergoes jumps between photon
number states. We select ensembles of field realizations evolving from a given
Fock st... | 0809.1511v1 |
2008-09-17 | Spin-transfer torque induced reversal in magnetic domains | Using the complex stereographic variable representation for the macrospin,
from a study of the nonlinear dynamics underlying the generalized
Landau-Lifshitz(LL) equation with Gilbert damping, we show that the
spin-transfer torque is effectively equivalent to an applied magnetic field. We
study the macrospin switching o... | 0809.2910v1 |
2008-10-01 | Excitation of trapped oscillations in discs around black holes | High-frequency quasi-periodic oscillations detected in the light curves of
black hole candidates can, according to one model, be identified with
hydrodynamic oscillations of the accretion disc. We describe a non-linear
coupling mechanism, suggested by Kato, through which inertial waves trapped in
the inner regions of a... | 0810.0116v1 |
2008-10-09 | Atomistic spin dynamics of the CuMn spin glass alloy | We demonstrate the use of Langevin spin dynamics for studying dynamical
properties of an archetypical spin glass system. Simulations are performed on
CuMn (20% Mn) where we study the relaxation that follows a sudden quench of the
system to the low temperature phase. The system is modeled by a Heisenberg
Hamiltonian whe... | 0810.1645v1 |
2008-10-20 | On the Existence of Exponentially Decreasing Solutions of the Nonlinear Landau Damping Problem | In this paper we prove the existence of a large class of periodic solutions
of the Vlasov-Poisson in one space dimension that decay exponentially as t goes
to infinity. The exponential decay is well known for the linearized version of
the Landau damping problem and it has been proved in [4] for a class of
solutions of ... | 0810.3456v2 |
2008-10-22 | Thermal (in)stability of type I collagen fibrils | We measured Young's modulus at temperatures ranging from 20 to 100 ^{\circ}$C
for a collagen fibril taken from rat's tendon. The hydration change under
heating and the damping decrement were measured as well. At physiological
temperatures $25-45^{\circ}$C Young's modulus decreases, which can be
interpreted as instabili... | 0810.4172v1 |
2008-11-03 | Ion thermal effects in oscillating multi-ion plasma sheath theory | The effects of ion temperature are discussed in a two-ion electron plasma and
for a model applicable to the oscillating sheath theory that has recently been
much in the focus of researchers. The differences between the fluid and kinetic
models have been pointed out, as well as the differences between the
approximative ... | 0811.0251v1 |
2008-12-01 | Self-Diffusion in 2D Dusty Plasma Liquids: Numerical Simulation Results | We perform Brownian dynamics simulations for studying the self-diffusion in
two-dimensional (2D) dusty plasma liquids, in terms of both mean-square
displacement and velocity autocorrelation function (VAF). Super-diffusion of
charged dust particles has been observed to be most significant at infinitely
small damping rat... | 0812.0338v3 |
2008-12-11 | Reduced nonlinear description of Farley-Buneman instability | In the study on nonlinear wave-wave processes in an ionosphere and a
magnetosphere usually the main attention is paid to investigation of plasma
turbulence at well developed stage, when the wide spectrum of plasma wave is
present. On the other side, it is well known that even if the number of
cooperating waves remains ... | 0812.2182v1 |
2008-12-16 | Reconstructing Baryon Oscillations: A Lagrangian Theory Perspective | Recently Eisenstein and collaborators introduced a method to `reconstruct'
the linear power spectrum from a non-linearly evolved galaxy distribution in
order to improve precision in measurements of baryon acoustic oscillations. We
reformulate this method within the Lagrangian picture of structure formation,
to better u... | 0812.2905v3 |
2009-02-16 | Plasmon excitations in homogeneous neutron star matter | We study the possible collective plasma modes which can affect neutron-star
thermodynamics and different elementary processes in the baryonic density range
between nuclear saturation ($\rho_0$) and $3\rho_0$. In this region, the
expected constituents of neutron-star matter are mainly neutrons, protons,
electrons and mu... | 0902.2552v2 |
2009-02-27 | Monogamy Inequality and Residual Entanglement of Three Qubits under Decoherence | Exploring an analytical expression for the convex roof of the pure state
squared concurrence for rank 2 mixed states the entanglement of a system of
three particles under decoherence is studied, using the monogamy inequality for
mixed states and the residual entanglement obtained from it. The monogamy
inequality is inv... | 0903.0019v2 |
2009-03-12 | X-band crab cavities for the CLIC beam delivery system | The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the
extraction of spent beams. In order to recover the luminosity lost through the
crossing angle a crab cavity is proposed to rotate the bunches prior to
collision. The crab cavity is chosen to have the same frequency as the main
linac (11.9942 GH... | 0903.2116v1 |
2009-03-16 | Regularity of invariant sets in semilinear damped wave equations | Under fairly general assumptions, we prove that every compact invariant
subset $\mathcal I$ of the semiflow generated by the semilinear damped wave
equation \epsilon u_{tt}+u_t+\beta(x)u-\sum_{ij}(a_{ij}
(x)u_{x_j})_{x_i}&=f(x,u),&& (t,x)\in[0,+\infty[\times\Omega,
u&=0,&&(t,x)\in[0,+\infty[\times\partial\Omega in $H^1... | 0903.2782v1 |
2009-03-20 | Hawking-Unruh radiation as irreversible consequence of radiative action in dynamics | Hawking-Unruh thermal state of warm surrounding field encountered in
non-inertial frames is shown to be a real phenomenon, a marker of nonstationary
dynamic evolutions. In accelerated motion of a charged particle it is shown
that the recoiled damping effect of Larmor radiation relaxation leads to
distinctive thermal po... | 0903.3529v2 |
2009-03-25 | The covering factor of high redshift damped Lyman-$α$ systems | We have used the Very Long Baseline Array to image 18 quasars with foreground
damped Lyman-$\alpha$ systems (DLAs) at 327, 610 or 1420 MHz, to measure the
covering factor $f$ of each DLA at or near its redshifted HI 21cm line
frequency. Including six systems from the literature, we find that none of 24
DLAs at $0.09 < ... | 0903.4483v1 |
2009-04-15 | Size dependent Acoustic Phonon Dynamics of CdTe0.68Se0.32 Nanoparticles in Borosilicate glass | Low frequency acoustic vibration and phonon linewidth for CdTe0.68Se0.32
nanoparticle embedded in borosilicate glass are calculated using two different
approaches by considering the elastic continuum model and fixed boundary
condition. The presence of medium significantly affects the phonon peaks and
results into the b... | 0904.2278v1 |
2009-04-19 | Incorporating Human Body Mass in Standards of Helmet Impact Protection against Traumatic Brain Injury | Impact induced traumatic brain injury (ITBI) describes brain injury from head
impact not necessarily accompanied by skull fracture. For sufficiently abrupt
head impact decelerations, ITBI results from brain tissue stress incurred as
the brain crashes into the inside of the skull wall, displacing the surrounding
cerebra... | 0904.2856v1 |
2009-04-21 | Type II migration of planets on eccentric orbits | The observed extrasolar planets possess both large masses (with a median M
sin i of 1.65 MJ) and a wide range in orbital eccentricity (0 < e < 0.94). As
planets are thought to form in circumstellar disks, one important question in
planet formation is determining whether, and to what degree, a gaseous disk
affects an ec... | 0904.3336v1 |
2009-05-13 | J-transform applied to the detection of Gravitational Waves: preliminary results | We propose to apply to the detection of Gravitational Waves a new method
developed for the spectral analysis of noisy time-series of damped oscillators.
From the Pad\'e Approximations of the time-series Z-transform, a Jacobi
Matrix (J-Matrix) is constructed. We show that the J-Matrix has bound states
with eigenvalues... | 0905.2000v1 |
2009-05-25 | Non-Markovian dynamics of a biased qubit coupled to a structured bath | A new analytical approach, beyond rotating wave approximation, based on
unitary transformations and the non-Markovian master equation for the density
operator, is applied to treat the biased spin boson model with a Lorentzian
structured bath for arbitrary detunings at zero temperature. Compared to zero
bias, we find th... | 0905.3965v3 |
2009-05-28 | A black box method for solving the complex exponentials approximation problem | A common problem, arising in many different applied contexts, consists in
estimating the number of exponentially damped sinusoids whose weighted sum best
fits a finite set of noisy data and in estimating their parameters. Many
different methods exist to this purpose. The best of them are based on
approximate Maximum Li... | 0905.4602v2 |
2009-06-10 | GALEX Discovery of a Damped Ly-alpha System at Redshift z = 1 | We report the first discovery of a QSO damped Ly-alpha (DLA) system by the
GALEX satellite. The system was initially identified as an MgII absorption-line
system (z_abs=1.028) in the spectrum of SDSS QSO J0203-0910 (z_em=1.58). The
presence of unusually strong absorption due to metal lines of ZnII, CrII, MnII,
and FeII... | 0906.2018v1 |
2009-06-11 | Longitudinal Stability of Recycler Bunches; Part I: Thresholds for Loss of Landau Damping | We examine the stability of intense flat bunches in barrier buckets used in
the Recycler. We consider some common stationary distributions and show that
they would be unstable against rigid dipole oscillations. We then discuss an
analytical model for the line density that best describes measured bunch
profiles. We incl... | 0906.2188v1 |
2009-06-15 | Regge poles of the Schwarzschild black hole: a WKB approach | We provide simple and accurate analytical expressions for the Regge poles of
the Schwarzschild black hole. This is achieved by using third-order WKB
approximations to solve the radial wave equations for spins 0, 1 and 2. These
results permit us to obtain analytically the dispersion relation and the
damping of the "surf... | 0906.2601v3 |
2009-06-30 | Cooling a magnetic resonance force microscope via the dynamical back-action of nuclear spins | We analyze the back-action influence of nuclear spins on the motion of the
cantilever of a magnetic force resonance microscope. We calculate the
contribution of nuclear spins to the damping and frequency shift of the
cantilever. We show that, at the Rabi frequency, the energy exchange between
the cantilever and the spi... | 0906.5420v2 |
2009-07-03 | Magnetic interference patterns in long disordered Josephson junctions | We study a diffusive superconductor - normal metal - superconductor (SNS)
junction in an external magnetic field. In the limit of a long junction, we
find that the form of the dependence of the Josephson current on the field and
on the length of the junction depends on the ratio between the junction width
and the lengt... | 0907.0632v3 |
2009-07-12 | Symmetries shape the current in ratchets induced by a bi-harmonic force | Equations describing the evolution of particles, solitons, or localized
structures, driven by a zero-average, periodic, external force, and invariant
under time reversal and a half-period time shift, exhibit a ratchet current
when the driving force breaks these symmetries. The bi-harmonic force
$f(t)=\epsilon_1\cos(q \... | 0907.2029v2 |
2009-07-21 | AFM Dissipation Topography of Soliton Superstructures in Adsorbed Overlayers | In the atomic force microscope, the nanoscale force topography of even
complex surface superstructures is extracted by the changing vibration
frequency of a scanning tip. An alternative dissipation topography with similar
or even better contrast has been demonstrated recently by mapping the
(x,y)-dependent tip damping ... | 0907.3585v4 |
2009-07-24 | Harmonic damped oscillators with feedback. A Langevin study | We consider a system in direct contact with a thermal reservoir and which, if
left unperturbed, is well described by a memory-less equilibrium Langevin
equation of the second order in the time coordinate. In such conditions, the
strength of the noise fluctuations is set by the damping factor, in accordance
with the Flu... | 0907.4309v1 |
2009-08-19 | Quantum Energy Teleportation with Electromagnetic Field: Discrete vs. Continuous Variables | It is well known that usual quantum teleportation protocols cannot transport
energy. Recently, new protocols called quantum energy teleportation (QET) have
been proposed, which transport energy by local operations and classical
communication with the ground states of many-body quantum systems. In this
paper, we compare... | 0908.2674v2 |
2009-08-25 | Designing materials for plasmonic systems | We use electronic structure calculations based upon density functional theory
to search for ideal plasmonic materials among the alkali noble intermetallics.
Importantly, we use density functional perturbation theory to calculate the
electron-phonon interaction and from there use a first order solution to the
Boltzmann ... | 0908.3707v1 |
2009-09-15 | Quantum critical points of Helical Fermi Liquids | Following our previous work, we study the quantum phase transitions which
spontaneously develop ferromagnetic spin order in helical fermi liquids which
breaks continuous spin-space rotation symmetry, with application to the edge
states of 3d topological band insulators. With finite fermi surface, the
critical point has... | 0909.2647v3 |
2009-09-25 | Evidence for Landau's critical velocity in superfluid helium nanodroplets from wave packet dynamics of attached potassium dimers | Femtosecond pump-probe spectroscopy has been used to study vibrational
dynamics of potassium dimers attached to superfluid helium nanodroplets.
Comparing the measured data with theoretical results based on dissipative
quantum dynamics we propose that the most important effect of the helium
environment is a general damp... | 0909.4691v1 |
2009-10-23 | Fragmentation of the photoabsorption strength in neutral and charged metal microclusters | The line shape of the plasma resonance in both neutral and charged small
sodium clusters is calculated. The overall properties of the multipeak
structure observed in the photoabsorption cross section of spherical Na_8 and
Na_20 neutral clusters can be understood in terms of Landau damping. Quantal
configurations are sh... | 0910.4576v1 |
2009-10-28 | Quantum Decoherence of Two Qubits | It is commonly stated that decoherence in open quantum systems is due to
growing entanglement with an environment. In practice, however, surprisingly
often decoherence may equally well be described by random unitary dynamics
without invoking a quantum environment at all. For a single qubit, for
instance, pure decoheren... | 0910.5364v1 |
2009-10-29 | System-reservoir dynamics of quantum and classical correlations | We address the system-reservoir dynamics of classical and quantum
correlations in the decoherence phenomenon, regarding a two qubit composite
system interacting with two independent environments. The most common noise
channels (amplitude damping, phase damping, bit flip, bit-phase flip, and phase
flip) was studied. By ... | 0910.5711v3 |
2009-11-04 | Nonlinear damping in a micromechanical oscillator | Nonlinear elastic effects play an important role in the dynamics of
microelectromechanical systems (MEMS). Duffing oscillator is widely used as an
archetypical model of mechanical resonators with nonlinear elastic behavior. In
contrast, nonlinear dissipation effects in micromechanical oscillators are
often overlooked. ... | 0911.0833v2 |
2009-11-04 | Solar-like oscillations in massive main-sequence stars. I. Asteroseismic signatures of the driving and damping regions | Motivated by the recent detection of stochastically excited modes in the
massive star V1449 Aql (Belkacem et al., 2009b), already known to be a $\beta$
Cephei, we theoretically investigate the driving by turbulent convection. By
using a full non-adiabatic computation of the damping rates, together with a
computation of... | 0911.0908v1 |
2009-11-11 | Ginzburg-Landau equation for dynamical four-wave mixing in gain nonlinear media with relaxation | We consider the dynamical degenerate four-wave mixing (FWM) model in a cubic
nonlinear medium including both the time relaxation of the induced nonlinearity
and the nonlocal coupling. The initial ten-dimensional FWM system can be
rewritten as a three-variable intrinsic system (namely the intensity pattern,
the amplitud... | 0911.2129v1 |
2009-12-10 | Bipartite quantum channels using multipartite cluster-type entangled coherent states | We propose a particular encoding for bipartite entangled states derived from
multipartite cluster-type entangled coherent states (CTECSs). We investigate
the effects of amplitude damping on the entanglement content of this bipartite
state, as well as its usefulness as a quantum channel for teleportation. We
find intere... | 0912.1949v2 |
2009-12-18 | Oscillatory transient regime in the forced dynamics of a spin torque nano-oscillator | We demonstrate that the transient non-autonomous dynamics of a spin torque
nano-oscillator (STNO) under a radio-frequency (rf) driving signal is
qualitatively different from the dynamics described by the Adler model. If the
external rf current $I_{rf}$ is larger than a certain critical value $I_{cr}$
(determined by the... | 0912.3650v1 |
2009-12-19 | Study of sdO models: mode trapping | We present the first description of mode trapping for sdO models. Mode
trapping of gravity modes caused by the He/H chemical transition is found for a
particular model, providing a selection effect for high radial order trapped
modes. Low- and intermediate-radial order {\em p}-modes (mixed modes with a
majority of node... | 0912.3911v1 |
2009-12-20 | Optimal Design of Fuzzy Based Power System Stabilizer Self Tuned by Robust Search Algorithm | In the interconnected power system network, instability problems are caused
mainly by the low frequency oscillations of 0.2 to 2.5 Hz. The supplementary
control signal in addition with AVR and high gain excitation systems are
provided by means of Power System Stabilizer (PSS). Conventional power system
stabilizers prov... | 0912.3960v2 |
2009-12-23 | Decoherence and Entanglement Dynamics in Fluctuating Fields | We study pure phase damping of two qubits due to fluctuating fields. As
frequently employed, decoherence is thus described in terms of random unitary
(RU) dynamics, i.e., a convex mixture of unitary transformations. Based on a
separation of the dynamics into an average Hamiltonian and a noise channel, we
are able to an... | 0912.4654v2 |
2009-12-30 | Spin torque and critical currents for magnetic vortex nano-oscillator in nanopillars | We calculated the main dynamic parameters of the spin polarized current
induced magnetic vortex oscillations in nanopillars, such as the range of
current density, where a vortex steady oscillations exist, the oscillation
frequency and orbit radius. We accounted for both the non-linear vortex
frequency and non-linear vo... | 0912.5521v1 |
2010-01-02 | Distinguishing quantum channels via magic squares game | We study the effect of quantum memory in magic squares game when played in
quantum domain. We consider different noisy quantum channels and analyze their
influence on the magic squares quantum pseudo-telepathy game. We show that the
probability of success can be used to distinguish the quantum channels. It is
seen that... | 1001.0295v1 |
2010-01-15 | Calculating Green Functions from Finite Systems | In calculating Green functions for interacting quantum systems numerically
one often has to resort to finite systems which introduces a finite size level
spacing. In order to describe the limit of system size going to infinity
correctly, one has to introduce an artificial broadening larger than the finite
size level di... | 1001.2750v1 |
2010-02-03 | Nonlinear stability of viscous roll waves | Extending results of Oh--Zumbrun and Johnson--Zumbrun for parabolic
conservation laws, we show that spectral stability implies nonlinear stability
for spatially periodic viscous roll wave solutions of the one-dimensional St.
Venant equations for shallow water flow down an inclined ramp. The main new
issues to be overco... | 1002.0788v2 |
2010-02-05 | Damped-driven KdV and effective equation for long-time behaviour of its solutions | For the damped-driven KdV equation $$ \dot
u-\nu{u_{xx}}+u_{xxx}-6uu_x=\sqrt\nu \eta(t,x), x\in S^1, \int u dx\equiv
\int\eta dx\equiv0, $$ with $0<\nu\le1$ and smooth in $x$ white in $t$ random
force $\eta$, we study the limiting long-time behaviour of the KdV integrals of
motions $(I_1,I_2,...)$, evaluated along a so... | 1002.1294v1 |
2010-02-09 | Fate of non-Fermi liquid behavior in QED$_{3}$ at finite chemical potential | The damping rate of two-dimensional massless Dirac fermions exhibit non-Fermi
liquid behavior, $\propto \epsilon^{1/2}$, due to gauge field at zero
temperature and zero chemical potential. We study the fate of this behavior at
finite chemical potential. We fist calculate explicitly the temporal and
spatial components o... | 1002.1760v3 |
2010-02-18 | Direct Evidence for Two-Fluid Effects in Molecular Clouds | We present a combination of theoretical and simulation-based examinations of
the role of two-fluid ambipolar drift on molecular line widths. The dissipation
provided by ion-neutral interactions can produce a significant difference
between the widths of neutral molecules and the widths of ionic species,
comparable to th... | 1002.3443v1 |
2010-03-08 | Potential mechanical loss mechanisms in bulk materials for future gravitational wave detectors | Low mechanical loss materials are needed to further decrease thermal noise in
upcoming gravitational wave detectors. We present an analysis of the
contribution of Akhieser and thermoelastic damping on the experimental results
of resonant mechanical loss measurements. The combination of both processes
allows the fit of ... | 1003.1613v1 |
2010-03-31 | Non-Markovian master equation for a damped oscillator with time-varying parameters | We derive an exact non-Markovian master equation that generalizes the
previous work [Hu, Paz and Zhang, Phys. Rev. D {\bf 45}, 2843 (1992)] to damped
harmonic oscillators with time-varying parameters. This is achieved by
exploiting the linearity of the system and operator solution in Heisenberg
picture. Our equation go... | 1003.5975v1 |
2010-04-08 | Doppler cooling a microsphere | Doppler cooling the center-of-mass motion of an optically levitated
microsphere via the velocity dependent scattering force from narrow whispering
gallery mode (WGM) resonances is described. Light that is red detuned from the
WGM resonance can be used to damp the center-of-mass motion in a process
analogous to the Dopp... | 1004.1443v1 |
2010-05-17 | Concerning the statistics of cosmic magnetism | Magnetic fields appear to be a generic feature of the early universe and are
a natural source of secondary CMB non-Gaussianity. In recent years the
statistical nature of the stresses of a primordial magnetic field has been well
studied. In this paper we confirm and extend these studies at one- and
two-point level, and ... | 1005.2982v1 |
2010-06-12 | Mechanical filtering in forced-oscillation of two coupled pendulums | Forced oscillation of a system composed of two pendulums coupled by a spring
in the presence of damping is investigated. In the steady state and within the
small angle approximation we solve the system equations of motion and obtain
the amplitudes and phases of in terms of the frequency of the sinusoidal
driving force.... | 1006.2475v1 |
2010-07-28 | Minimization of phonon-tunneling dissipation in mechanical resonators | Micro- and nanoscale mechanical resonators have recently emerged as
ubiquitous devices for use in advanced technological applications, for example
in mobile communications and inertial sensors, and as novel tools for
fundamental scientific endeavors. Their performance is in many cases limited by
the deleterious effects... | 1007.4948v1 |
2010-08-05 | Linear and Non-Linear Landau Resonance of Kinetic Alfvén Waves: Consequences for Electron Distribution and Wave Spectrum in the Solar Wind | Kinetic Alfven wave turbulence in solar wind is considered and it is shown
that non-Maxwellian electron distribution function has a significant effect on
the dynamics of the solar wind plasmas. Linear Landau damping leads to the
formation of a plateau in the parallel electron distribution function which
diminishes the ... | 1008.0993v1 |
2010-08-11 | Theory for a dissipative droplet soliton excited by a spin torque nanocontact | A novel type of solitary wave is predicted to form in spin torque oscillators
when the free layer has a sufficiently large perpendicular anisotropy. In this
structure, which is a dissipative version of the conservative droplet soliton
originally studied in 1977 by Ivanov and Kosevich, spin torque counteracts the
dampin... | 1008.1898v1 |
2010-08-18 | Modulation stabilization of Bloch oscillations of two-component Bose-Einstein condensates in optical lattices | We study the Bloch oscillations (BOs) of two-component Bose-Einstein
condensates (BECs) trapped in spin-dependent optical lattices. Based on the
derived equations of motion of the wave packet in the basis of localized wave
functions of the lattice sites, the damping effect induced by the
intercomponent and intracompone... | 1008.3004v1 |
2010-08-19 | Josephson Coupling and Fiske Dynamics in Ferromagnetic Tunnel Junctions | We report on the fabrication of Nb/AlO_x/Pd_{0.82}Ni_{0.18}/Nb
superconductor/insulator/ferromagnetic metal/superconductor (SIFS) Josephson
junctions with high critical current densities, large normal resistance times
area products, high quality factors, and very good spatial uniformity. For
these junctions a transitio... | 1008.3341v1 |
2010-09-03 | A Simple Numerical Absorbing Layer Method in Elastodynamics | The numerical analysis of elastic wave propagation in unbounded media may be
difficult to handle due to spurious waves reflected at the model artificial
boundaries. Several sophisticated techniques such as nonreflecting boundary
conditions, infinite elements or absorbing layers (e.g. Perfectly Matched
Layers) lead to a... | 1009.0592v1 |
2010-09-09 | Modulation of waves due to charge-exchange collisions in magnetized partially ionized space plasma | A nonlinear time dependent fluid simulation model is developed that describes
the evolution of magnetohydrodynamic waves in the presence of collisional and
charge exchange interactions of a partially ionized plasma. The partially
ionized plasma consists of electrons, ions and a significant number of neutral
atoms. In o... | 1009.1859v1 |
2010-10-01 | Ferromagnetic resonance study of Co/Pd/Co/Ni multilayers with perpendicular anisotropy irradiated with Helium ions | We present a ferromagnetic resonance (FMR) study of the effect of Helium ion
irradiation on the magnetic anisotropy, the linewidth and the Gilbert damping
of a Co/Ni multilayer coupled to Co/Pd bilayers. The perpendicular magnetic
anisotropy decreases linearly with He ion fluence, leading to a transition to
in-plane ma... | 1010.0268v2 |
2010-10-08 | A unified first-principles study of Gilbert damping, spin-flip diffusion and resistivity in transition metal alloys | Using a formulation of first-principles scattering theory that includes
disorder and spin-orbit coupling on an equal footing, we calculate the
resistivity $\rho$, spin flip diffusion length $l_{sf}$ and the Gilbert damping
parameter $\alpha$ for Ni$_{1-x}$Fe$_x$ substitutional alloys as a function of
$x$. For the techn... | 1010.1626v3 |
2010-10-12 | Movers and shakers: Granular damping in microgravity | The response of an oscillating granular damper to an initial perturbation is
studied using experiments performed in microgravity and granular dynamics
mulations. High-speed video and image processing techniques are used to extract
experimental data. An inelastic hard sphere model is developed to perform
simulations and... | 1010.2343v1 |
2010-10-20 | Modified Landau levels, damped harmonic oscillator and two-dimensional pseudo-bosons | In a series of recent papers one of us has analyzed in some details a class
of elementary excitations called {\em pseudo-bosons}. They arise from a special
deformation of the canonical commutation relation $[a,a^\dagger]=\1$, which is
replaced by $[a,b]=\1$, with $b$ not necessarily equal to $a^\dagger$. Here,
after a ... | 1010.4221v1 |
2010-11-16 | Forcibly driven coherent soft phonons in GeTe with intense THz-rate pump fields | We propose an experimental technique to generate large amplitude coherent
phonons with irradiation of THz-rate pump pulses and to study the dynamics of
phase transition in GeTe ferroelectrics. When a single pump pulse irradiates
the sample at various pump power densities, the frequency of the soft phonon
decreases sub-... | 1011.3624v2 |
2010-11-23 | Ultra-fast magnetisation rates within the Landau-Lifshitz-Bloch model | The ultra-fast magnetisation relaxation rates during the laser-induced
magnetisation process are analyzed in terms of the Landau-Lifshitz-Bloch (LLB)
equation for different values of spin $S$. The LLB equation is equivalent in
the limit $S \rightarrow \infty$ to the atomistic Landau-Lifshitz-Gilbert (LLG)
Langevin dyna... | 1011.5054v1 |
2010-11-26 | Dependence of entanglement on initial states under amplitude damping channel in non-inertial frames | Under amplitude damping channel, the dependence of the entanglement on the
initial states $|\Theta>_{1}$ and $|\Theta>_{2}$, which reduce to four
orthogonal Bell states if we take the parameter of states $\alpha=\pm
1/\sqrt{2}$ are investigated. We find that the entanglements for different
initial states will decay alo... | 1011.5700v3 |
2010-12-21 | Characterization of Decoherence from an Environmental Perspective | For the case of phase damping (pure decoherence) we investigate the extent to
which environmental traits are imprinted on an open quantum system. The
dynamics is described using the quantum channel approach. We study what the
knowledge of the channel may reveal about the nature of its underlying dynamics
and, conversel... | 1012.4685v1 |
2010-12-28 | Quantum Leptogenesis I | Thermal leptogenesis explains the observed matter-antimatter asymmetry of the
universe in terms of neutrino masses, consistent with neutrino oscillation
experiments. We present a full quantum mechanical calculation of the generated
lepton asymmetry based on Kadanoff-Baym equations. Origin of the asymmetry is
the depart... | 1012.5821v3 |
2011-01-06 | Chemical Enrichment in the Carbon-enhanced Damped Lyman $α$ System | We show that the recently observed elemental abundance pattern of the
carbon-rich metal-poor Damped Lyman $\alpha$ (DLA) system is in excellent
agreement with the nucleosynthesis yields of faint core-collapse supernovae of
primordial stars. The observed abundance pattern is not consistent with the
nucleosynthesis yield... | 1101.1227v2 |
2011-02-08 | Quantization of Damping Particle Based On New Variational Principles | In this paper a new approach is proposed to quantize mechanical systems whose
equations of motion can not be put into Hamiltonian form. This approach is
based on a new type of variational principle, which is adopted to a describe a
relation: a damping particle may shares a common phase curve with a free
particle, whose... | 1102.1573v2 |
2011-02-15 | Spin dynamics in the strong spin-orbit coupling regime | We study the spin dynamics in a high-mobility two dimensional electron gas
(2DEG) with generic spin-orbit interactions (SOIs). We derive a set of spin
dynamic equations which capture the purely exponential to the damped
oscillatory spin evolution modes observed in different regimes of SOI strength.
Hence we provide a f... | 1102.3170v1 |
2011-02-22 | Ab-initio calculation of the Gilbert damping parameter via linear response formalism | A Kubo-Greenwood-like equation for the Gilbert damping parameter $\alpha$ is
presented that is based on the linear response formalism. Its implementation
using the fully relativistic Korringa-Kohn-Rostoker (KKR) band structure method
in combination with Coherent Potential Approximation (CPA) alloy theory allows
it to b... | 1102.4551v1 |
2011-03-03 | Collective modes and the speed of sound in the Fulde-Ferrell-Larkin-Ovchinnikov state | We consider the density response of a spin-imbalanced ultracold Fermi gas in
an optical lattice in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. We
calculate the collective mode spectrum of the system in the generalised random
phase approximation and find that though the collective modes are damped even
at zero te... | 1103.0696v2 |
2011-03-10 | Shocks in financial markets, price expectation, and damped harmonic oscillators | Using a modified damped harmonic oscillator model equivalent to a model of
market dynamics with price expectations, we analyze the reaction of financial
markets to shocks. In order to do this, we gather data from indices of a
variety of financial markets for the 1987 Black Monday, the Russian crisis of
1998, the crash ... | 1103.1992v2 |
2011-03-22 | Inductive determination of the optimum tunnel barrier thickness in magnetic tunnelling junction stacks for spin torque memory applications | We use pulsed inductive microwave magnetometry to study the precessional
magnetization dynamics of the free layer in CoFeB/MgO/CoFeB based magnetic
tunnelling junction stacks with varying MgO barrier thickness. From the field
dependence of the precession frequency we are able to derive the uniaxial
anisotropy energy an... | 1103.4248v1 |
2011-04-11 | Algebraic damping in the one-dimensional Vlasov equation | We investigate the asymptotic behavior of a perturbation around a spatially
non homogeneous stable stationary state of a one-dimensional Vlasov equation.
Under general hypotheses, after transient exponential Landau damping, a
perturbation evolving according to the linearized Vlasov equation decays
algebraically with th... | 1104.1890v2 |
2011-05-06 | System-environment dynamics of X-type states in noninertial frames | The system-environment dynamics of noninertial systems is investigated. It is
shown that for the amplitude damping channel: (i) the biggest difference
between the decoherence effect and the Unruh radiation on the dynamics of the
entanglement is the former only leads to entanglement transfer in the whole
system, but the... | 1105.1216v2 |
2011-05-10 | Spontaneous magnon decays in planar ferromagnet | We predict that spin-waves in an easy-plane ferromagnet have a finite
lifetime at zero temperature due to spontaneous decays. In zero field the
damping is determined by three-magnon decay processes, whereas decays in the
two-particle channel dominate in a transverse magnetic field. Explicit
calculations of the magnon d... | 1105.1893v1 |
2011-05-19 | Scaling of the higher-order flow harmonics: implications for initial-eccentricity models and the "viscous horizon" | The scaling properties of the flow harmonics for charged hadrons $v_{n}$ and
their ratios $[ v_n/(v_2)^{n/2}]_{n\geq 3}$, are studied for a broad range of
transverse momenta ($p_T$) and centrality selections in Au+Au and Pb+Pb
collisions at $\sqrt{s_{NN}}=0.2 \text{and} 2.76$ TeV respectively. At
relatively low $p_T$, ... | 1105.3782v2 |
2011-05-26 | Dynamics in the production of superheavy nuclei in low-energy heavy-ion collisions | We present a review of the recent progress of theoretical models on the
description of the formation of superheavy nuclei in collisions of heavy
systems. Two sorts of reactions that are the fusion-evaporation mechanism and
the massive damped collisions to produce superheavy nuclei are discussed.
Problems and further im... | 1105.5224v2 |
2011-06-01 | Effect of detuning on the phonon induced dephasing of optically driven InGaAs/GaAs quantum dots | Recently, longitudinal acoustic phonons have been identified as the main
source of the intensity damping observed in Rabi rotation measurements of the
ground-state exciton of a single InAs/GaAs quantum dot. Here we report
experiments of intensity damped Rabi rotations in the case of detuned laser
pulses, the results ha... | 1106.0142v1 |
2011-06-03 | Shear viscous effects on the primordial power spectrum from warm inflation | We compute the primordial curvature spectrum generated during warm inflation,
including shear viscous effects. The primordial spectrum is dominated by the
thermal fluctuations of the radiation bath, sourced by the dissipative term of
the inflaton field. The dissipative coefficient \Upsilon, computed from first
principl... | 1106.0701v1 |
2011-06-06 | Weakly nonlinear stochastic CGL equations | We consider the linear Schr\"odinger equation under periodic boundary
condition, driven by a random force and damped by a quasilinear damping: $$
\frac{d}{dt}u+i\big(-\Delta+V(x)\big) u=\nu \Big(\Delta u-\gr |u|^{2p}u-i\gi
|u|^{2q}u \Big) +\sqrt\nu\, \eta(t,x).\qquad (*) $$ The force $\eta$ is white
in time and smooth ... | 1106.1158v1 |
2011-06-09 | Investigating viscous damping using a webcam | We describe an experiment involving a mass oscillating in a viscous fluid and
analyze viscous damping of harmonic motion. The mechanical oscillator is
tracked using a simple webcam and an image processing algorithm records the
position of the geometrical center as a function of time. Interesting
information can be extr... | 1106.1823v1 |
2011-06-11 | Conformal and covariant formulation of the Z4 system with constraint-violation damping | We present a new formulation of the Einstein equations based on a conformal
and traceless decomposition of the covariant form of the Z4 system. This
formulation combines the advantages of a conformal decomposition, such as the
one used in the BSSNOK formulation (i.e. well-tested hyperbolic gauges, no need
for excision,... | 1106.2254v2 |
2011-06-14 | Oscillations of hot, young neutron stars: Gravitational wave frequencies and damping times | We study how the frequencies and damping times of oscillations of a newly
born, hot proto-neutron star depend on the physical quantities which
characterize the star quasi-stationary evolution which follows the bounce.
Stellar configurations are modeled using a microscopic equation of state
obtained within the Brueckner... | 1106.2736v1 |
2011-06-22 | Samll BGK waves and nonlinear Landau damping (higher dimensions) | Consider Vlasov-Poisson system with a fixed ion background and periodic
condition on the space variables, in any dimension d\geq2. First, we show that
for general homogeneous equilibrium and any periodic x-box, within any small
neighborhood in the Sobolev space W_{x,v}^{s,p} (p>1,s<1+(1/p)) of the steady
distribution f... | 1106.4368v1 |
2011-07-13 | Increased Brownian force noise from molecular impacts in a constrained volume | We report on residual gas damping of the motion of a macroscopic test mass
enclosed in a nearby housing in the molecular flow regime. The damping
coefficient, and thus the associated thermal force noise, is found to increase
significantly when the distance between test mass and surrounding walls is
smaller than the tes... | 1107.2520v1 |
2011-07-13 | Dimension of attractors and invariant sets of damped wave equations in unbounded domains | Under fairly general assumptions, we prove that every compact invariant set
$\mathcal I$ of the semiflow generated by the semilinear damped wave equation
u_{tt}+\alpha u_t+\beta(x)u-\Deltau = f(x,u), (t,x)\in[0,+\infty[\times\Omega,
u = 0, (t,x)\in[0,+\infty[\times\partial\Omega in $H^1_0(\Omega)\times
L^2(\Omega) has ... | 1107.2589v1 |
2011-07-20 | Bayesian Magnetohydrodynamic Seismology of Coronal Loops | We perform a Bayesian parameter inference in the context of resonantly damped
transverse coronal loop oscillations. The forward problem is solved in terms of
parametric results for kink waves in one-dimensional flux tubes in the thin
tube and thin boundary approximations. For the inverse problem, we adopt a
Bayesian ap... | 1107.3943v1 |
2011-07-31 | Evolution of cat states in a dissipative parametric amplifier: decoherence and entanglement | The evolution of the Schr\"{o}dinger-cat states in a dissipative parametric
amplifier is examined. The main tool in the analysis is the normally ordered
characteristic function. Squeezing, photon-number distribution and reduced
factorial moments are discussed for the single- and compound-mode cases. Also
the single-mod... | 1108.0127v1 |
2011-07-31 | Second-Order, Dissipative Tâtonnement: Economic Interpretation and 2-Point Limit Cycles | This paper proposes an alternative to the classical price-adjustment
mechanism (called "t\^{a}tonnement" after Walras) that is second-order in time.
The proposed mechanism, an analogue to the damped harmonic oscillator, provides
a dynamic equilibration process that depends only on local information. We show
how such a ... | 1108.0188v3 |
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