publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2012-06-05 | Effects of Variable Newton Constant During Inflation | In this paper the effects of time-dependent Newton constant G during
inflation are studied. We present the formalism of curvature perturbations in
an inflationary system with a time-dependent Newton constant. As an example we
consider a toy model in which G undergoes a sudden change during inflation. By
imposing the ap... | 1206.0903v2 |
2013-09-05 | Spherical steady accretion flows -- dependence on the cosmological constant, exact isothermal solutions and applications to cosmology | We investigate spherical, isothermal and polytropic steady accretion models
in the presence of the cosmological constant. Exact solutions are found for
three classes of isothermal fluids, assuming the test gas approximation. The
cosmological constant damps the mass accretion rate and - above certain limit -
completely ... | 1309.1252v1 |
2014-07-02 | Basins of attraction in forced systems with time-varying dissipation | We consider dissipative periodically forced systems and investigate cases in
which having information as to how the system behaves for constant dissipation
may be used when dissipation varies in time before settling at a constant final
value. First, we consider situations where one is interested in the basins of
attrac... | 1407.0556v1 |
2017-12-21 | An Adaptive Passivity-Based Controller of a Buck-Boost Converter With a Constant Power Load | This paper addresses the problem of regulating the output voltage of a DC-DC
buck-boost converter feeding a constant power load,which is a problem of
current practical interest. Designing a stabilising controller is theoretically
challenging because its average model is a bilinear second order system that,
due to the p... | 1712.07792v1 |
2023-08-03 | Quasinormal modes of the spherical bumblebee black holes with a global monopole | The bumblebee model is an extension of the Einstein-Maxwell theory that
allows for the spontaneous breaking of the Lorentz symmetry of the spacetime.
In this paper, we study the quasinormal modes of the spherical black holes in
this model that are characterized by a global monopole. We analyze the two
cases with a vani... | 2308.01575v1 |
2009-08-12 | Linear Fractionally Damped Oscillator | In this paper the linearly damped oscillator equation is considered with the
damping term generalized to a Caputo fractional derivative. The order of the
derivative being considered is 0 less than or equal to nu which is less than or
equal to 1 . At the lower end, nu = 0, the equation represents an un-damped
oscillator... | 0908.1683v1 |
1998-02-23 | Shell Effects on Rotational Damping in Superdeformed Nuclei | Damping of rotational motion in superdeformed Hg and Dy-region nuclei is
studied by means of cranked shell model diagonalization. It is shown that a
shell oscillation in single-particle alignments affects significantly
properties of rotational damping. Onset properties of damping and damping width
for Hg are quite diff... | 9802065v1 |
2003-08-29 | Influence of radiative damping on the optical-frequency susceptibility | Motivated by recent discussions concerning the manner in which damping
appears in the electric polarizability, we show that (a) there is a dependence
of the nonresonant contribution on the damping and that (b) the damping enters
according to the "opposite sign prescription." We also discuss the related
question of how ... | 0309001v1 |
2024-03-19 | Weakly elliptic damping gives sharp decay | We prove that weakly elliptic damping gives sharp energy decay for the
abstract damped wave semigroup, where the damping is not in the functional
calculus. In this case, there is no overdamping. We show applications in
linearised water waves and Kelvin--Voigt damping. | 2403.13067v1 |
2015-05-15 | Reliable Damping of Free Surface Waves in Numerical Simulations | This paper generalizes existing approaches for free-surface wave damping via
momentum sinks for flow simulations based on the Navier-Stokes equations. It is
shown in 2D flow simulations that, to obtain reliable wave damping, the
coefficients in the damping functions must be adjusted to the wave parameters.
A scaling la... | 1505.04087v2 |
2019-02-25 | Resonant absorption as a damping mechanism for the transverse oscillations of the coronal loops observed by SDO/AIA | Solar coronal loops represent the variety of fast, intermediate, and slow
normal mode oscillations. In this study, the transverse oscillations of the
loops with a few-minutes period and also with damping caused by the resonant
absorption were analyzed using extreme ultraviolet (EUV) images of the Sun. We
employed the 1... | 1902.09649v1 |
2016-08-08 | Damping Functions correct over-dissipation of the Smagorinsky Model | This paper studies the time-averaged energy dissipation rate $\langle
\varepsilon_{SMD} (u)\rangle$ for the combination of the Smagorinsky model and
damping function. The Smagorinsky model is well known to over-damp. One common
correction is to include damping functions that reduce the effects of model
viscosity near w... | 1608.02655v2 |
2018-03-19 | Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature | We perform global and local analysis of oscillatory and damped spherically
symmetric fundamental solutions for Helmholtz operators
$\big({-}\Delta\pm\beta^2\big)$ in $d$-dimensional, $R$-radius hyperbolic
${\mathbf H}_R^d$ and hyperspherical ${\mathbf S}_R^d$ geometry, which
represent Riemannian manifolds with positive... | 1803.07149v2 |
2005-01-02 | Effect of dipolar interactions on the magnetization of a cubic array of nanomagnets | We investigated the effect of intermolecular dipolar interactions on a cubic
3D ensemble of 5X5X4=100 nanomagnets, each with spin $S = 5$. We employed the
Landau-Lifshitz-Gilbert equation to solve for the magnetization $M(B)$ curves
for several values of the damping constant $\alpha$, the induction sweep rate,
the latt... | 0501006v2 |
2015-03-16 | Habitability of waterworlds: runaway greenhouses, atmospheric expansion and multiple climate states of pure water atmospheres | There are four different stable climate states for pure water atmospheres, as
might exist on so-called "waterworlds". I map these as a function of solar
constant for planets ranging in size from Mars size to 10 Earth-mass. The
states are: globally ice covered (Ts< 245K), cold and damp (270 < Ts< 290K),
hot and moist (3... | 1503.04835v1 |
2001-08-07 | Dynamics and Origin of the 2:1 Orbital Resonances of the GJ 876 Planets | (Abridged) A dynamical fit has placed the two planets about the star GJ 876
in coplanar orbits deep in 3 resonances at the 2:1 mean-motion commensurability
with small libration amplitudes. The libration of both lowest order mean-motion
resonance variables, theta_1 and theta_2, and the secular resonance variable,
theta_... | 0108104v2 |
2007-09-25 | On the Structure of Dark Matter Halos at the Damping Scale of the Power Spectrum with and without Relict Velocities | We report a series of high-resolution cosmological N-body simulations
designed to explore the formation and properties of dark matter halos with
masses close to the damping scale of the primordial power spectrum of density
fluctuations. We further investigate the effect that the addition of a random
component, v_rms, i... | 0709.4027v1 |
2009-11-18 | Slow Diffusive Gravitational Instability Before Decoupling | Radiative diffusion damps acoustic modes at large comoving wavenumber (k)
before decoupling (``Silk damping''). In a simple WKB analysis, neglecting
moments of the temperature distribution beyond the quadrupole, damping appears
in the acoustic mode as a term of order ik^2/(taudot) where taudot is the
scattering rate pe... | 0911.3665v1 |
2010-04-02 | Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk | We model the time variability of ~9,000 spectroscopically confirmed quasars
in SDSS Stripe 82 as a damped random walk. Using 2.7 million photometric
measurements collected over 10 years, we confirm the results of Kelly et al.
(2009) and Koz{\l}owski et al. (2010) that this model can explain quasar light
curves at an im... | 1004.0276v2 |
2013-01-21 | Mass-metallicity relation from z=5 to the present: Evidence for a transition in the mode of galaxy growth at z=2.6 due to the end of sustained primordial gas infall | We analyze the redshift evolution of the mass-metallicity relation in a
sample of 110 Damped Ly$\alpha$ absorbers spanning the redshift range
$z=0.11-5.06$ and find that the zero-point of the correlation changes
significantly with redshift. The evolution is such that the zero-point is
constant at the early phases of ga... | 1301.5013v2 |
2013-02-13 | Low mass planets in protoplanetary disks with net vertical magnetic fields: the Planetary Wake and Gap Opening | We study wakes and gap opening by low mass planets in gaseous protoplanetary
disks threaded by net vertical magnetic fields which drive
magnetohydrodynamical (MHD) turbulence through the magnetorotational instabilty
(MRI), using three dimensional simulations in the unstratified local shearing
box approximation. The wak... | 1302.3239v1 |
2015-08-03 | Using coronal seismology to estimate the magnetic field strength in a realistic coronal model | Coronal seismology is extensively used to estimate properties of the corona,
e.g. the coronal magnetic field strength are derived from oscillations observed
in coronal loops. We present a three-dimensional coronal simulation including a
realistic energy balance in which we observe oscillations of a loop in
synthesised ... | 1508.00593v1 |
2021-08-05 | Small-scale clumping at recombination and the Hubble tension | Despite the success of the standard $\Lambda$CDM model of cosmology, recent
data improvements have made tensions emerge between low- and high-redshift
observables, most importantly in determinations of the Hubble constant $H_0$
and the (rescaled) clustering amplitude $S_8$. The high-redshift data, from the
cosmic micro... | 2108.02747v3 |
2022-05-29 | Modeling the Dynamics of the Coronavirus SARS-CoV-2 Pandemic using Modified SIR Model with the 'Damped-Oscillator' Dynamics of the Effective Reproduction Number | The COVID-19 pandemic has been a great catastrophe that upended human lives
and caused millions of deaths all over the world. The rapid spread of the
virus, with its early-stage exponential growth and subsequent 'waves', caught
many medical professionals and decision-makers unprepared. Even though
epidemiological model... | 2205.14747v1 |
2023-08-05 | Modulating Spin Current Induced Effective Damping in $β-W/Py$ Heterostructures by a Systematic Variation in Resistivity of the Sputtered Deposited $β-W$ films | Utilizing the spin-induced pumping from a ferromagnet (FM) into a heavy metal
(HM) under the ferromagnetic resonance (FMR) condition, we report an
enhancement in effective damping in $\beta$- W/Py bilayers by systematically
varying resistivity ($\rho_{W}$) of $\beta$-W films. Different resistivity
ranging from 100 $\mu... | 2308.02939v1 |
2023-12-26 | Observation of Magnon Damping Minimum Induced by Kondo Coupling in a van der Waals Ferromagnet Fe$_{3-x}$GeTe$_{2}$ | In heavy-fermion systems with $f$ electrons, there is an intricate interplay
between Kondo screening and magnetic correlations, which can give rise to
various exotic phases. Recently, similar interplay appears to also occur in
$d$-electron systems, but the underlying mechanism remains elusive. Here, using
inelastic neu... | 2312.15961v1 |
2022-07-13 | Probing Bardeen-Kiselev black hole with cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds | In this work, we investigate a static and spherically symmetric
Bardeen-Kiselev black hole with cosmological constant which is a solution of
the Einstein-non-linear Maxwell field equations along with a quintessential
field. We compute the quasinormal frequencies for Bardeen-Kiselev black
hole(BH) with cosmological cons... | 2207.05907v4 |
1997-10-23 | Power Spectra for Cold Dark Matter and its Variants | The bulk of recent cosmological research has focused on the adiabatic cold
dark matter model and its simple extensions. Here we present an accurate
fitting formula that describes the matter transfer functions of all common
variants, including mixed dark matter models. The result is a function of
wavenumber, time, and s... | 9710252v1 |
2004-11-13 | K-shell Photoabsorption of Oxygen Ions | Extensive calculations of the atomic data required for the spectral modelling
of the K-shell photoabsorption of oxygen ions have been carried out in a
multi-code approach. The present level energies and wavelengths for the highly
ionized species (electron occupancies 2 <= N <= 4) are accurate to within 0.5
eV and 0.02 ... | 0411374v2 |
2005-12-12 | Most precise single redshift bound to the variability of the fine-structure constant | Verification of theoretical predictions of an oscillating behavior of the
fine-structure constant, alpha, with cosmic time requires high precision
measurements at individual redshifts, while in earlier studies the mean Delta
alpha/alpha values averaged over wide redshift intervals were usually reported.
This requiremen... | 0512287v1 |
2000-11-29 | Corrugation of Roads | We present a one dimensional model for the development of corrugations in
roads subjected to compressive forces from a flux of cars. The cars are modeled
as damped harmonic oscillators translating with constant horizontal velocity
across the surface, and the road surface is subject to diffusive relaxation. We
derive di... | 0011510v2 |
2005-07-28 | Theory of transverse spin dynamics in a polarized Fermi liquid and an itinerant ferromagnet | The linear equations for transverse spin dynamics in a weakly polarized
degenerate Fermi liquid with arbitrary relationship between temperature and
polarization are derived from Landau-Silin phenomenological kinetic equation
with general form of two-particle collision integral. Unlike the previous
treatment where Fermi... | 0507675v1 |
2006-04-21 | Dynamic approach for micromagnetics close to the Curie temperature | In conventional micromagnetism magnetic domain configurations are calculated
based on a continuum theory for the magnetization which is assumed to be of
constant length in time and space. Dynamics is usually described with the
Landau-Lifshitz-Gilbert (LLG) equation the stochastic variant of which includes
finite temper... | 0604508v1 |
2004-10-08 | An Effective Field Theory at Finite Density | An effective theory to treat the dense nuclear medium by the perturbative
expansion method is proposed as a natural extension of the Heavy Baryon Chiral
Perturbation Theory (HBChPT). Treating the Fermi momentum scale as a separate
scale of the system, we get an improved convergence and the conceptually clear
interpreta... | 0410124v1 |
2006-10-16 | Multichannel calculation of the very narrow $D_{s0}^*(2317)$ and the very broad $D_0^*(2300-2400)$ | The narrow $D_{s0}^{\ast}$(2317) and broad $D_0^{\ast}$(2300-2400) charmed
scalar mesons and their radial excitations are described in a coupled-channel
quark model that also reproduces the properties of the light scalar nonet. All
two-meson channels containing ground-state pseudoscalars and vectors are
included. The p... | 0610188v1 |
1997-10-03 | Zero-Temperature Casimir Fluctuations and the Limits of Force Microscope Sensitivity | It is predicted that in force microscopy the quantum fluctuations responsible
for the Casimir force can be directly observed as temperature-independent force
fluctuations having spectral density $9\pi/(40\ln(4/e)) \hbar \delta k$, where
$\hbar$ is Planck's constant and $\delta k$ is the observed change in spring
consta... | 9710017v3 |
2001-01-16 | Transient QED effects in absorbing dielectrics | The spontaneous emission rate of a radiating atom reaches its
time-independent equilibrium value after an initial transient regime. In this
paper we consider the associated relaxation effects of the spontaneous decay
rate of atoms in dispersive and absorbing dielectric media for atomic
transition frequencies near mater... | 0101075v1 |
2009-02-16 | A polycrystalline graphite model for the 2175 Angstrom interstellar extinction band | A random, hydrogen-free, assembly of microscopic sp2 carbon chips, forming a
macroscopically homogeneous and isotropic solid, is proposed as a model carrier
for the UV interstellar extinction band . The validity of this model is based
on the calculation of the Bruggeman average dielectric function of a mixture of
the k... | 0902.2637v1 |
2009-04-18 | Brownian Dynamics of charged particles in a constant magnetic field | Numerical algorithms are proposed for simulating the Brownian dynamics of
charged particles in an external magnetic field, taking into account the
Brownian motion of charged particles, damping effect and the effect of magnetic
field self-consistently. Performance of these algorithms is tested in terms of
their accuracy... | 0904.2849v1 |
2009-05-18 | Far-infrared optical excitations in multiferroic TbMnO_3 | We provide a detailed study of the reflectivity of multiferroic TbMnO_3 for
wave numbers from 40 cm^{-1} to 1000 cm^{-1} and temperatures 5 K < T < 300 K.
Excitations are studied for polarization directions E || a, the polarization
where electromagnons are observed, and for E || c, the direction of the
spontaneous pola... | 0905.2921v1 |
2009-11-08 | Complete characterization and synthesis of the response function of elastodynamic networks | The response function of a network of springs and masses, an elastodynamic
network, is the matrix valued function $W(\omega)$, depending on the frequency
$\omega$, mapping the displacements of some accessible or terminal nodes to the
net forces at the terminals. We give necessary and sufficient conditions for a
given f... | 0911.1501v1 |
2012-05-31 | Resonance Plasmon Linewidth Oscillations in Spheroidal Metallic Nanoparticle Embedded in a Dielectric Matrix | The kinetic approach is applied to calculate oscillations of a surface
plasmon linewidth in a spheroidal metal nanoparticle embedded in any dielectric
media. The principal attention is focused on the case, when the free electron
path is much greater than the particle size.
The linewidth of the plasmon resonance as a ... | 1205.6959v2 |
2012-06-21 | Direct Observation of Massless Domain Wall Dynamics in Nanostripes with Perpendicular Magnetic Anisotropy | Domain wall motion induced by nanosecond current pulses in nanostripes with
perpendicular magnetic anisotropy (Pt/Co/AlO$_x$) is shown to exhibit
negligible inertia. Time-resolved magnetic microscopy during current pulses
reveals that the domain walls start moving, with a constant speed, as soon as
the current reaches ... | 1206.4967v1 |
2015-06-10 | Tunable inertia of chiral magnetic domain walls | The time it takes to accelerate an object from zero to a given velocity
depends on the applied force and the environment. If the force ceases, it takes
exactly the same time to completely decelerate. A magnetic domain wall (DW) is
a topological object that has been observed to follow this behavior. Here we
show that ac... | 1506.03490v2 |
2015-06-23 | The Vlasov-Poisson System for Stellar Dynamics in Spaces of Constant Curvature | We obtain a natural extension of the Vlasov-Poisson system for stellar
dynamics to spaces of constant Gaussian curvature $\kappa\ne 0$: the unit
sphere $\mathbb S^2$, for $\kappa>0$, and the unit hyperbolic sphere $\mathbb
H^2$, for $\kappa<0$. These equations can be easily generalized to higher
dimensions. When the pa... | 1506.07090v1 |
2015-06-24 | Holographic Tunneling Wave Function | The Hartle-Hawking wave function in cosmology can be viewed as a decaying
wave function with anti-de Sitter (AdS) boundary conditions. We show that the
growing wave function in AdS familiar from Euclidean AdS/CFT is equivalent,
semiclassically and up to surface terms, to the tunneling wave function in
cosmology. The co... | 1506.07374v2 |
2015-11-19 | Memory effects and active Brownian diffusion | A self-propelled artificial microswimmer is often modeled as a ballistic
Brownian particle moving with constant speed aligned along one of its axis, but
changing direction due to random collisions with the environment. Similarly to
thermal noise, its angular randomization is described as a memoryless
stochastic process... | 1511.06113v1 |
2016-05-12 | Phase coexistence and spatial correlations in reconstituting k-mer models | In reconstituting k-mer models, extended objects which occupy several sites
on a one dimensional lattice, undergo directed or undirected diffusion, and
reconstitute -when in contact- by transferring a single monomer unit from one
k-mer to the other; the rates depend on the size of participating k-mers. This
polydispers... | 1605.03859v2 |
2016-10-20 | Evolving Planck Mass in Classically Scale-Invariant Theories | We consider classically scale-invariant theories with non-minimally coupled
scalar fields, where the Planck mass and the hierarchy of physical scales are
dynamically generated. The classical theories possess a fixed point, where
scale invariance is spontaneously broken. In these theories, however, the
Planck mass becom... | 1610.06571v3 |
2017-01-30 | Regularized solutions for some backward nonlinear parabolic equations with statistical data | In this paper, we study the backward problem of determining initial condition
for some class of nonlinear parabolic equations in multidimensional domain
where data are given under random noise. This problem is ill-posed, i.e., the
solution does not depend continuously on the data. To regularize the instable
solution, w... | 1701.08459v2 |
2017-11-17 | Cosmological abundance of the QCD axion coupled to hidden photons | We study the cosmological evolution of the QCD axion coupled to hidden
photons. For a moderately strong coupling, the motion of the axion field leads
to an explosive production of hidden photons by tachyonic instability. We use
lattice simulations to evaluate the cosmological abundance of the QCD axion. In
doing so, we... | 1711.06590v2 |
2017-12-28 | Eddy diffusivity of quasi-neutrally-buoyant inertial particles | We investigate the large-scale transport properties of
quasi-neutrally-buoyant inertial particles carried by incompressible zero-mean
periodic or steady ergodic flows. We show how to compute large-scale indicators
such as the inertial-particle terminal velocity and eddy diffusivity from first
principles in a perturbati... | 1712.10049v1 |
2018-06-28 | Transient thermal characterization of suspended monolayer MoS$_2$ | We measure the thermal time constants of suspended single layer molybdenum
disulfide drums by their thermomechanical response to a high-frequency
modulated laser. From this measurement the thermal diffusivity of single layer
MoS$_2$ is found to be 1.14 $\times$ 10$^{-5}$ m$^2$/s on average. Using a
model for the therma... | 1806.10769v1 |
2018-09-12 | The relaxation time of OH bond for hydrogen impurity in LiNbO3 | The one dimensional model for the dynamic of hydrogen in lithium niobate is
explained by adopting Morse potential. The diffused hydrogen substitutes
Lithium and it makes bonding with one oxygen atom of a facet of
oxygen-triangle. The bonds will be stretched to set up anharmonic vibration.
The damped anharmonic oscillat... | 1810.01959v1 |
2019-04-19 | Semi-implicit methods for the dynamics of elastic sheets | Recent applications (e.g. active gels and self-assembly of elastic sheets)
motivate the need to efficiently simulate the dynamics of thin elastic sheets.
We present semi-implicit time stepping algorithms to improve the time step
constraints that arise in explicit methods while avoiding much of the
complexity of fully-i... | 1904.09198v1 |
2019-06-02 | Analytical prediction of logarithmic Rayleigh scattering in amorphous solids from tensorial heterogeneous elasticity with power-law disorder | The damping or attenuation coefficient of sound waves in solids due to
impurities scales with the wavevector to the fourth power, also known as
Rayleigh scattering. In amorphous solids, Rayleigh scattering may be enhanced
by a logarithmic factor although computer simulations offer conflicting
conclusions regarding this... | 1906.00372v3 |
2019-09-10 | Voltage regulation in buck--boost coniverters feeding an unknown constant power load: an adaptive passivity-based control | Rapid developments in power distribution systems and renewable energy have
widened the applications of dc--dc buck--boost converters in dc voltage
regulation. Applications include vehicular power systems, renewable energy
sources that generate power at a low voltage, and dc microgrids. It is noted
that the cascade--con... | 1909.04438v1 |
2020-06-18 | Quasinormal modes and Hawking radiation of black holes in cubic gravity | We consider quasinormal modes and Hawking radiation of four-dimensional
asymptotically flat black holes in the most general up
to-cubic-order-in-curvature dimension-independent Einsteinian theory of gravity
that shares its graviton spectrum with the Einstein theory on constant
curvature backgrounds. We show that dampin... | 2006.10462v4 |
2020-07-28 | Pair emission from a relativistic domain wall in antiferromagnets | Magnon emission and excitation by a relativistic domain wall at a constant
velocity in antiferromagnet is theoretically studied. A pair emission due to a
quadratic magnon coupling is shown to be dominant. The emission corresponds in
the comoving frame to a vacuum polarization induced by a zero-energy
instability of the... | 2007.13939v1 |
2020-09-25 | Exciton-polariton mediated interaction between two nitrogen-vacancy color centers in diamond using two-dimensional transition metal dichalcogenides | In this paper, starting from a quantum master equation, we discuss the
interaction between two negatively charged Nitrogen-vacancy color centers in
diamond via exciton-polaritons propagating in a two-dimensional transition
metal dichalcogenide layer in close proximity to a diamond crystal. We focus on
the optical 1.945... | 2009.12194v1 |
2020-10-11 | Coordinate-space representation of a charged scalar particle propagator in a constant magnetic field expanded as a sum over the Landau levels | A coordinate-space representation for a charged scalar particle propagator in
a constant magnetic field was obtained as a series over the Landau levels.
Using the recently developed modified Fock-Schwinger method, an intermediate
expression was constructed and symmetrized, thus, allowing for factorization of
the series... | 2010.05195v2 |
2020-10-12 | Robustness of the Cosmological Constant Damping Mechanism Through Matter Eras | A dynamical resolution to the cosmological constant fine-tuning problem has
been previously put forward, based on a scalar-tensor gravitational theory
possessing de Sitter attractor solutions characterized by a small Hubble
expansion rate, irrespective of an initially large vacuum energy. We show that
a technically nat... | 2010.05927v2 |
2021-05-25 | Gravitational Waves in a Closed Spacetime via Deviation Equation | Within the closed universe, we obtain the amplitude and frequency of
gravitational waves in the terms of discrete wave numbers, wave propagation
time, and cosmological constant using the deviation equation in the first-order
perturbed metric. We demonstrate that the cosmological constant effect on GWs
is only seen in t... | 2105.11690v1 |
2022-03-14 | The influence of the medium physical conditions and atomic constants on the Stokes profiles of absorption lines in the solar spectrum | The Stokes profiles of Fe I lines in the photosphere of the Sun are
calculated within the Unno-Beckers-Landi-Dagl`Innocenti theory. Estimates of
the magnetic strengthening of the lines were obtained. The changes in the
Stokes profiles depending on the excitation potential, wavelength, equivalent
width, Lande factor, mi... | 2203.06867v1 |
2022-10-06 | Information scrambling of the dilute Bose gas at low temperature | We calculate the quantum Lyapunov exponent $\lambda_L$ and butterfly velocity
$v_B$ in the dilute Bose gas at temperature $T$ deep in the Bose-Einstein
condensation phase. The generalized Boltzmann equation approach is used for
calculating out-of-time ordered correlators, from which $\lambda_L$ and $v_B$
are extracted.... | 2210.03025v2 |
2023-06-16 | Short-term evolution of electron wave packet in a constant crossed field with radiative corrections | We study the dynamics of an electron wave packet in a strong constant crossed
electromagnetic field with account for radiative corrections due to interaction
of the electron with the vacuum fluctuations. We evaluate a wave packet
composed of the solutions to the Dyson-Schwinger equation, which describes
electron propag... | 2306.09932v1 |
2023-12-11 | Accelerated Gradient Dynamics on Riemannian Manifolds: Faster Rate and Trajectory Convergence | In order to minimize a differentiable geodesically convex function, we study
a second-order dynamical system on Riemannian manifolds with an asymptotically
vanishing damping term of the form $\alpha/t$. For positive values of $\alpha$,
convergence rates for the objective values and convergence of trajectory is
derived.... | 2312.06366v1 |
1994-02-02 | Constraints on the Models for Structure Formation from the Abundance of Damped Lyman Alpha Systems | Models for structure formation attempt to predict the power spectrum of
density perturbations in the present universe from the initial power spectrum
and the nature of dark matter. Observational constraints on the power spectrum
at different scales in the present epoch can, therefore, be used to eliminate
(or choose be... | 9402006v1 |
1994-02-04 | Damped Lyman Alpha Systems and Galaxy Formation | We examine the constraints on theories of galaxy formation that are obtained
from observations of damped $\lya$ (DL) systems, assuming they are gaseous
protodisks in dark matter halos. Using the Press-Schechter formalism, we find
that the mixed dark matter model, with $\ohdm = 0.3$, $\ocdm = 0.65$, $\obaryon
= 0.05$, a... | 9402014v1 |
1997-09-02 | Estimating the mass density of neutral gas at $z < 1$ | We use the relationships between galactic HI mass and B-band luminosity
determined by Rao & Briggs to recalculate the mass density of neutral gas at
the present epoch based on more recent measures of the galaxy luminosity
function than were available to those authors. We find $\Omega_{gas}(z=0)
\simeq 5 \times 10^{-4}$... | 9709014v1 |
1997-10-02 | Dust and elemental abundances in Damped Ly alpha absorbers | The effects of the dust on the determination of elemental abundances in
damped Ly alpha (DLA) absorbers are investigated. Relations between the
observed abundances measured in the gas phase and the overall abundances (gas
plus dust) are derived as a function of dust-to-gas ratio, metallicity,
element-to-element abundan... | 9710026v1 |
1998-10-29 | Runaway Heating By R-modes of Neutron Stars in Low Mass X-ray Binaries | Recently Andersson et. al., and Bildsten have independently suggested that an
r-mode instability might be responsible for stalling the neutron-star spin-up
in strongly accreting, Low Mass X-ray Binaries (LMXBs). We show that if this
does occur, then there are two possibilities for the resulting neutron-star
evolution:
... | 9810471v1 |
2000-04-04 | Radiative Precession of an Isolated Neutron Star | Euler's equations of motion are derived exactly for a rigid, triaxial,
internally frictionless neutron star spinning down electromagnetically in
vacuo. It is shown that the star precesses, but not freely: its regular
precession relative to the principal axes of inertia couples to the component
of the radiation torque a... | 0004035v1 |
2002-08-22 | Effects of Resonance in Quasiperiodic Oscillators of Neutron Star Binaries | Using a large quantity of Rossi X-ray Timing Explorer data presented in the
literature I offer a detailed investigation into the accuracy of quasiperiodic
oscillations (QPO) frequency determination. The QPO phenomenon seen in X-ray
binaries is possibly a result of the resonance of the intrinsic (eigen)
oscillations and... | 0208423v1 |
2004-03-10 | The early build-up of dust in galaxies: A study of Damped Ly alpha Systems | We present a study of the early build-up of dust in high redshift galaxies.
The study is based on the analysis of 38 Damped Ly alpha systems (DLAs) for
which we derive the fraction of iron atoms in dust form, f_{Fe}. The sample is
representative of metal-poor galaxies in the redshift range 0.6 </= z </= 3.4
selected on... | 0403237v1 |
2004-07-22 | The Chemical Composition of Alpha Centauri A: Strong Lines and the ABO Theory of Collisional Line Broadening | The mean abundances of Mg, Si, Ca, Ti, Cr and Fe based on both strong and
weak lines of Alpha Centauri A are determined by matching the observed line
profiles with those synthesized from stellar atmospheric models and comparing
these results with a similar analysis for the Sun. There is good agreement
between the abund... | 0407468v1 |
2006-08-07 | The Complex Gap in Color Superconductivity | We solve the gap equation for color-superconducting quark matter in the 2SC
phase, including both the energy and the momentum dependence of the gap,
\phi=\phi(k_0,\vk). For that purpose a complex Ansatz for \phi is made. The
calculations are performed within an effective theory for cold and dense quark
matter. The solu... | 0608020v2 |
2006-10-11 | Superfluid-normal phase transition in finite systems and its effect on damping of hot giant resonances | Thermal fluctuations of quasiparticle number are included making use of the
secondary Bogolyubov's transformation, which turns quasiparticles operators
into modified-quasiparticle ones. This restores the unitarity relation for the
generalized single-particle density operator, which is violated within the
Hartree-Fock-B... | 0610047v1 |
1995-03-31 | Dissipative Quantum Systems with Potential Barrier. General Theory and Parabolic Barrier | We study the real time dynamics of a quantum system with potential barrier
coupled to a heat-bath environment. Employing the path integral approach an
evolution equation for the time dependent density matrix is derived. The time
evolution is evaluated explicitly near the barrier top in the temperature
region where quan... | 9503027v1 |
2007-07-17 | Is a gas of strongly interacting atomic fermions a nearly perfect fluid? | We use all-optical methods to produce a highly-degenerate Fermi gas of
spin-1/2 $^6$Li atoms. A magnetic field tunes the gas near a collisional
(Feshbach) resonance, producing strong interactions between spin-up and
spin-down atoms. This atomic gas is a paradigm for strong interactions in
nature, and provides tests of ... | 0707.2574v1 |
2009-07-14 | Multi-mode entanglement of N harmonic oscillators coupled to a non-Markovian reservoir | Multi-mode entanglement is investigated in the system composed of $N$ coupled
identical harmonic oscillators interacting with a common environment. We treat
the problem very general by working with the Hamiltonian without the
rotating-wave approximation and by considering the environment as a
non-Markovian reservoir to... | 0907.2298v2 |
2009-10-20 | New searches for HI 21-cm in damped Lyman-alpha absorption systems | We present the results of three separate searches for HI 21-cm absorption in
a total of twelve damped Lyman-alpha absorption systems (DLAs) and sub-DLAs
over the redshift range z = 0.86-3.37. We find no absorption in the five
systems for which we obtain reasonable sensitivities and add the results to
those of other rec... | 0910.3742v2 |
2010-09-30 | An efficient numerical algorithm for the L2 optimal transport problem with applications to image processing | We present a numerical method to solve the optimal transport problem with a
quadratic cost when the source and target measures are periodic probability
densities. This method is based on a numerical resolution of the corresponding
Monge-Amp\`ere equation. We extend the damped Newton algorithm of Loeper and
Rapetti \cit... | 1009.6039v2 |
2011-06-28 | A refined empirical stability criterion for nonlinear Schroedinger solitons under spatiotemporal forcing | We investigate the dynamics of travelling oscillating solitons of the cubic
NLS equation under an external spatiotemporal forcing of the form $f(x,t) = a
\exp[iK(t)x]$. For the case of time-independent forcing a stability criterion
for these solitons, which is based on a collective coordinate theory, was
recently conje... | 1106.5609v1 |
2012-11-06 | Low-Energy Effective Field Theory for Chromo-Natural Inflation | Chromo-natural inflation is a novel model of inflation which relies on the
existence of non-abelian gauge fields interacting with an axion. In its
simplest realization, an SU(2) gauge field is assumed to begin inflation in a
rotationally invariant VEV. The dynamics of the gauge fields significantly
modifies the equatio... | 1211.1396v2 |
2013-11-22 | Multi-dimensional fractional wave equation and some properties of its fundamental solution | In this paper, a multi-dimensional fractional wave equation that describes
propagation of the damped waves is introduced and analyzed. In contrast to the
fractional diffusion-wave equation, the fractional wave equation contains
fractional derivatives of the same order $\alpha,\ 1\le \alpha \le 2$ both in
space and in t... | 1311.5920v1 |
2014-03-18 | The nature of Damped Lyman-α and MgII absorbers explored with their dust contents | We estimate the abundance of dust in damped Lyman-{\alpha} absorbers (DLAs)
by statistically measuring the excess reddening they induce on their background
quasars. We detect systematic reddening behind DLA consistent with the SMC type
reddening curve, but it is inconsistent with the Milky Way type reddening. We
find t... | 1403.4339v2 |
2014-06-15 | Dynamical topological phases in quenched spin-orbit coupled degenerate Fermi gas | The spin-orbit coupled degenerate Fermi gas provides a totally new platform
to realize topological superfluids and related topological excitations.
Previous studies have mainly focused on the properties of the ground state.
Here we consider a two-dimensional Fermi gas with Rashba spin-orbit coupling
subject to a perpen... | 1406.3821v2 |
2014-08-02 | Tunnel magnetoresistance and spin-transfer-torque switching in polycrystalline Co2FeAl full-Heusler alloy magnetic tunnel junctions on Si/SiO2 amorphous substrates | We studied polycrystalline B2-type Co2FeAl (CFA) full-Heusler alloy based
magnetic tunnel junctions (MTJs) fabricated on a Si/SiO2 amorphous substrate.
Polycrystalline CFA films with a (001) orientation, a high B2 ordering, and a
flat surface were achieved using a MgO buffer layer. A tunnel magnetoresistance
(TMR) rati... | 1408.0341v1 |
2014-08-12 | Landau Damping in Relativistic Plasmas | We examine the phenomenon of Landau Damping in relativistic plasmas via a
study of the relativistic Vlasov-Poisson system (rVP) on the torus for initial
data sufficiently close to a spatially uniform steady state. We find that if
the steady state is regular enough (essentially in a Gevrey class of degree in
a specified... | 1408.2666v2 |
2014-10-02 | Localized and propagating excitations in gapped phases of spin systems with bond disorder | Using the conventional $T$-matrix approach, we discuss gapped phases in 1D,
2D, and 3D spin systems (both with and without a long range magnetic order)
with bond disorder and with weakly interacting bosonic elementary excitations.
This work is motivated by recent experimental and theoretical activity in
spin-liquid-lik... | 1410.0712v1 |
2014-11-12 | Fundamental limits in heat assisted magnetic recording and methods to overcome it with exchange spring structures | The switching probability of magnetic elements for heat assisted recording is
investigated. It is found that FePt elements with a diameter of 5 nm and a
height of 10nm show, at a field of 0.5 T, thermally written in errors of 12
percent, which is significant too large for bit patterned magnetic recording.
Thermally wri... | 1411.3052v1 |
2014-11-25 | A framework for studying the effect of compliant surfaces on wall turbulence | This paper extends the resolvent formulation proposed by McKeon & Sharma
(2010) to consider turbulence-compliant wall interactions. Under this
formulation, the turbulent velocity field is expressed as a linear
superposition of propagating modes, identified via a gain-based decomposition
of the Navier-Stokes equations. ... | 1411.6690v2 |
2015-03-29 | ETEAPOT: symplectic orbit/spin tracking code for all-electric storage rings | Proposed methods for measuring the electric dipole moment (EDM) of the proton
use an intense, polarized proton beam stored in an all-electric storage ring
"trap". At the "magic" kinetic energy of 232.792 MeV, proton spins are
"frozen", for example always parallel to the instantaneous particle momentum.
This paper des... | 1503.08468v1 |
2015-06-03 | The anomalous transport of axial charge: topological vs non-topological fluctuations | Axial charge imbalance is an essential ingredient in novel effects associated
with chiral anomaly such as chiral magnetic effects (CME). In a non-Abelian
plasma with chiral fermions, local axial charge can be generated a) by
topological fluctuations which would create domains with non-zero winding
number b) by conventi... | 1506.01384v2 |
2015-08-06 | Characteristics of hybrid compact stars with a sharp hadron-quark interface | We describe two aspects of the physics of hybrid stars that have a sharp
interface between a core of quark matter and a mantle of nuclear matter.
Firstly, we analyze the mass-radius relation. We describe a generic "Constant
Speed of Sound" (CSS) parameterization of the quark matter equation of state
(EoS), in which t... | 1508.01261v2 |
2016-03-08 | Global effect of local skin friction drag reduction in spatially developing turbulent boundary layer | A numerical investigation of two locally applied drag reducing control
schemes is carried out in the configuration of a spatially developing turbulent
boundary layer (TBL). One control is designed to damp near-wall turbulence and
the other induces constant mass flux in the wall-normal direction. Both control
schemes yi... | 1603.02427v2 |
2016-09-23 | Influence of heavy metal materials on magnetic properties of Pt/Co/heavy metal tri-layered structures | Pt/Co/heavy metal (HM) tri-layered structures with interfacial perpendicular
magnetic anisotropy (PMA) are currently under intensive research for several
emerging spintronic effects, such as spinorbit torque, domain wall motion, and
room temperature skyrmions. HM materials are used as capping layers to generate
the str... | 1609.07320v2 |
2016-12-15 | Plasmons at the LaAlO$_3$/SrTiO$_3$ interface and Graphene-LaAlO$_3$/SrTiO$_3$ double layer | We study plasmon modes of the two-dimensional electron gas residing at the
interface of band insulators $\rm{LaAlO_3}$ and $\rm{SrTiO_3}$ (LAO/STO) and
the plasmon excitations of graphene-LAO/STO double layer as well. Considering
the electron-electron interaction within random phase approximation, we
calculate the plas... | 1612.04953v2 |
2017-06-22 | Full-counting statistics of transient energy current in mesoscopic systems | We investigate the full-counting statistics (FCS) of energy flow carried by
electrons in the transient regime. Based on two measurement scheme we formulate
a non-equilibrium Keldysh Green's function theory to compute the generating
function for FCS of energy transport. Specifically, we express the generating
function u... | 1706.07182v1 |
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