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2015-11-25
A Proposal of a Damping Term for the Relativistic Euler Equations
We introduce a damping term for the special relativistic Euler equations in $3$-D and show that the equations reduce to the non-relativistic damped Euler equations in the Newtonian limit. We then write the equations as a symmetric hyperbolic system for which local-in-time existence of smooth solutions can be shown.
1511.08183v1
2016-01-27
Concatenated Codes for Amplitude Damping
We discuss a method to construct quantum codes correcting amplitude damping errors via code concatenation. The inner codes are chosen as asymmetric Calderbank-Shor-Steane (CSS) codes. By concatenating with outer codes correcting symmetric errors, many new codes with good parameters are found, which are better than the ...
1601.07423v1
2016-03-29
Generalized damped Milne-Pinney equation and Chiellini method
We adopt the Chiellini integrability method to find the solutions of various generalizations of the damped Milne-Pinney equations. In particular, we find the solution of the damped Ermakov-Painlev\'e II equation and generalized dissipative Milne-Pinney equation.
1603.08747v2
2017-12-07
Damped wave equations on compact hyperbolic surfaces
We prove exponential decay of energy for solutions of the damped wave equation on compact hyperbolic surfaces with regular initial data as long as the damping is nontrivial. The proof is based on a similar strategy as in Dyatlov-Jin and in particular, uses the fractal uncertainty principle proved in Bourgain-Dyatlov.
1712.02692v1
2018-03-20
Stability of the wave equations on a tree with local Kelvin-Voigt damping
In this paper we study the stability problem of a tree of elastic strings with local Kelvin-Voigt damping on some of the edges. Under the compatibility condition of displacement and strain and continuity condition of damping coefficients at the vertices of the tree, exponential/polynomial stability are proved.
1803.07280v1
2018-09-10
Logarithmic Decay of a Wave Equation with Kelvin-Voigt Damping
In this paper we analyze the long time behavior of a wave equation with local Kelvin-Voigt Damping. Through introducing proper class symbol and pseudo-differential calculus, we obtain a Carleman estimate, and then establish an estimate on the corresponding resolvent operator. As a result, we show the logarithmic decay ...
1809.03196v1
2018-11-07
Slow-dissipation limit of the harmonic oscillator with general power-law damping
An approximate solution is presented for simple harmonic motion in the presence of damping by a force which is a general power-law function of the velocity. The approximation is shown to be quite robust, allowing for a simple way to investigate amplitude decay in the presence of general types of weak, nonlinear damping...
1811.02953v2
2019-09-25
Forced Coupled Duffing Oscillators with Nonlinear Damping: Resonance and Antiresonance
In this work, we investigate resonance and antiresonance behaviour in forced coupled Duffing oscillators with nonlinear damping. Further, we will analyse the parameter dependence of the frequency response and stability. In the course of all the analysis, emphasis shall be on how different damping mechanisms contrast ag...
1909.11390v1
2020-04-21
Damping rate limitations for transverse dampers in large hadron colliders
The paper focuses on two issues important for design and operation of bunch-by-bunch transverse damper in a very large hadron collider, where fast damping is required to suppress beam instabilities and noise induced emittance growth. The first issue is associated with kick variation along a bunch which affects the damp...
2004.10249v2
2021-08-17
Spectral enclosures for the damped elastic wave equation
In this paper we investigate spectral properties of the damped elastic wave equation. Deducing a correspondence between the eigenvalue problem of this model and the one of Lam\'e operators with non self-adjoint perturbations, we provide quantitative bounds on the location of the point spectrum in terms of suitable norm...
2108.07676v1
2022-02-10
Stochastic optimal control for nonlinear damped network dynamics
We present a stochastic optimal control problem for a tree network. The dynamics of the network are governed by transport equations with a special emphasis on the non-linear damping function. Demand profiles at the network sinks are modelled by a stochastic differential equations. An explicit optimal inflow into the ne...
2202.05114v1
2022-03-03
Conformal symmetry in damped Pais-Uhlenbeck oscillator
Two Lagrangian formulations for describing of the damped harmonic oscillator have been introduced by Bateman. For these models we construct higher derivative generalization which enjoys the l-conformal Newton-Hooke symmetry. The dynamics of generalized systems corresponds to the damped Pais-Uhlenbeck oscillator for a p...
2203.01651v1
2022-05-26
Ergodic results for the stochastic nonlinear Schrödinger equation with large damping
We study the nonlinear Schr\"odinger equation with linear damping, i.e. a zero order dissipation, and additive noise. Working in $R^d$ with d = 2 or d = 3, we prove the uniqueness of the invariant measure when the damping coefficient is sufficiently large.
2205.13364v1
2022-10-31
An adaptive damped Newton method for strongly monotone and Lipschitz continuous operator equations
We will consider the damped Newton method for strongly monotone and Lipschitz continuous operator equations in a variational setting. We will provide a very accessible justification why the undamped Newton method performs better than its damped counterparts in a vicinity of a solution. Moreover, in the given setting, a...
2210.17107v1
2022-11-19
Blow up and lifespan estimates for systems of semi-linear wave equations with damping and potential
In this paper, we consider the semi-linear wave systems with power-nonlinearities and a large class of space-dependent damping and potential. We obtain the same blow-up regions and the lifespan estimates for three types wave systems, compared with the systems without damping and potential.
2211.10639v1
2023-08-10
Pathwise uniqueness for stochastic heat and damped equations with Hölder continuous drift
In this paper, we prove pathwise uniqueness for stochastic differential equations in infinite dimension. Under our assumptions, we are able to consider the stochastic heat equation up to dimension $3$, the stochastic damped wave equation in dimension $1$ and the stochastic Euler-Bernoulli damped beam equation up to dim...
2308.05415v1
2023-10-30
Beliaev damping in Bose gas
According to the Bogoliubov theory the low energy behaviour of the Bose gas at zero temperature can be described by non-interacting bosonic quasiparticles called phonons. In this work the damping rate of phonons at low momenta, the so-called Beliaev damping, is explained and computed with simple arguments involving the...
2310.20070v1
2023-11-25
Energy scattering for the unsteady damped nonlinear Schrodinger equation
We investigate the large time behavior of the solutions to the nonlinear focusing Schr\"odinger equation with a time-dependent damping in the energy sub-critical regime. Under non classical assumptions on the unsteady damping term, we prove some scattering results in the energy space.
2311.14980v2
1995-03-13
Tidal Excitation of Modes in Binary Systems with Applications to Binary Pulsars
We consider the tidal excitation of modes in a binary system of arbitrary eccentricity. For a circular orbit, the modes generally undergo forced oscillation with a period equal to the orbital period ($T$). For an eccentric orbit, the amplitude of each tidally excited mode can be written approximately as the sum of an o...
9503053v1
1997-09-05
The Formation of Cosmic Structures in a Light Gravitino Dominated Universe
We analyse the formation of cosmic structures in models where the dark matter is dominated by light gravitinos with mass of $ 100$ eV -- 1 keV, as predicted by gauge-mediated supersymmetry (SUSY) breaking models. After evaluating the number of degrees of freedom at the gravitinos decoupling ($g_*$), we compute the tran...
9709047v1
1998-01-05
Calculation of the Ostriker-Vishniac Effect in Cold Dark Matter Models
We present a new derivation of the cosmic microwave background anisotropy spectrum from the Ostriker-Vishniac effect for an open, flat, or closed Universe, and calculate the anisotropy expected in cold dark-matter (CDM) models. We provide simple semi-analytic fitting formulas for the Vishniac power spectrum that can be...
9801022v3
1999-06-08
Constrained Violent Relaxation to a Spherical Halo
Violent relaxation during the collapse of a galaxy halo is known to be incomplete in realistic cases such as cosmological infall or mergers. We adopt a physical picture of strong but short lived interactions between potential fluctuations and particle orbits, using the broad framework outlined by Tremaine (1987) for in...
9906133v1
2000-02-21
Star Formation and Chemical Evolution of Lyman-Break Galaxies
The number density and clustering properties of Lyman-break galaxies (LBGs) observed at redshift $z\sim 3$ are best explained by assuming that they are associated with the most massive haloes at $z\sim 3$ predicted in hierarchical models of structure formation. In this paper we study, under the same assumption, how sta...
0002388v1
2000-03-12
Gravity-Modes in ZZ Ceti Stars: IV. Amplitude Saturation by Parametric Instability
ZZ Ceti stars exhibit small amplitude photometric pulsations in multiple gravity-modes. We demonstrate that parametric instability, a form of resonant 3-mode coupling, limits overstable modes to amplitudes similar to those observed. In particular, it reproduces the observed trend that longer period modes have larger am...
0003163v1
2000-10-18
Magnetic Helicity Conservation and Astrophysical Dynamos
We construct a magnetic helicity conserving dynamo theory which incorporates a calculated magnetic helicity current. In this model the fluid helicity plays a small role in large scale magnetic field generation. Instead, the dynamo process is dominated by a new quantity, derived from asymmetries in the second derivative...
0010373v2
2001-01-12
The Scaling of the Redshift Power Spectrum: Observations from the Las Campanas Redshift Survey
In a recent paper we have studied the redshift power spectrum $P^S(k,\mu)$ in three CDM models with the help of high resolution simulations. Here we apply the method to the largest available redshift survey, the Las Campanas Redshift Survey (LCRS). The basic model is to express $P^S(k,\mu)$ as a product of three factor...
0101211v2
2002-07-15
Atomic data for the K-vacancy states of Fe XXIV
As part of a project to compute improved atomic data for the spectral modeling of iron K lines, we report extensive calculations and comparisons of atomic data for K-vacancy states in Fe XXIV. The data sets include: (i) energy levels, line wavelengths, radiative and Auger rates; (ii) inner-shell electron impact excitat...
0207323v2
2002-12-17
Probing the Friedmann equation during recombination with future CMB experiments
We show that by combining measurements of the temperature and polarization anisotropies of the Cosmic Microwave Background (CMB), future experiments will tightly constrain the expansion rate of the universe during recombination. A change in the expansion rate modifies the way in which the recombination of hydrogen proc...
0212360v2
2003-10-08
The Sizes and Kinematic Structure of Absorption Systems Towards the Lensed Quasar APM08279+5255
We have obtained spatially resolved spectra of the z=3.911 triply imaged QSO APM08279+5255 using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). We study the line of sight equivalent width (EW) differences and velocity shear of high and low ionization absorbers (including a da...
0310221v1
2004-05-11
Photoionization Modeling and the K Lines of Iron
We calculate the efficiency of iron K line emission and iron K absorption in photoionized models using a new set of atomic data. These data are more comprehensive than those previously applied to the modeling of iron K lines from photoionized gases, and allow us to systematically examine the behavior of the properties ...
0405210v1
2005-05-23
Damped Lyman Alpha Surveys and Statistics - A Review
The history and progress of DLA research over the past several decades is reviewed here. Larger datasets and deeper surveys, particularly over the last couple of years, have improved our knowledge of the neutral gas content and distribution in the universe at all observable redshifts, including the present epoch. New r...
0505479v1
2005-06-28
The Metallicity - Kinematics Relation in Large-N(HI) Absorbers
Sloan Digital Sky Survey (SDSS) quasar spectroscopy is yielding a database of strong low-ionization MgII absorbers over the redshift interval 0.36<z<2.28 which is over two orders of magnitude larger than anything previously assembled. HST UV spectroscopy has been used to measure neutral hydrogen column densities for a ...
0506701v1
2006-11-28
Detecting cold gas at intermediate redshifts: GMRT survey using Mg II systems
Intervening HI 21-cm absorption systems at z > 1.0 are very rare and only 4 confirmed detections have been reported in the literature. Despite their scarcity, they provide interesting and unique insights into the physical conditions in the interstellar medium of high-z galaxies. Moreover, they can provide independent c...
0611836v1
1998-10-01
Finite temperature dynamics of vortices in the two dimensional anisotropic Heisenberg model
We study the effects of finite temperature on the dynamics of non-planar vortices in the classical, two-dimensional anisotropic Heisenberg model with XY- or easy-plane symmetry. To this end, we analyze a generalized Landau-Lifshitz equation including additive white noise and Gilbert damping. Using a collective variable...
9810011v1
2001-02-09
The influence of the oscillations of the chemical potential on the de Haas - van Alphen effect in quasi-two-dimensional compounds
The de Haas - van Alphen effect in quasi-two-dimensional metals is studied at arbitrary parameters. The oscillations of the chemical potential may substantially change the temperature dependence of harmonic amplitudes that is usually used to determine the effective electron mass. Hence, the processing of the experiment...
0102177v1
2003-11-11
Ornstein-Zernike equation and Percus-Yevick theory for molecular crystals
We derive the Ornstein-Zernike equation for molecular crystals of axially symmetric particles and apply the Percus-Yevick approximation to this system. The one-particle orientational distribution function has a nontrivial dependence on the orientation and is needed as an input. Despite some differences, the Ornstein-Ze...
0311253v1
2004-07-12
Microwave-induced flow of vortices in long Josephson junctions
We report experimental and numerical study of microwave-induced flow of vortices in long Josephson junctions at zero dc magnetic field. Our intriguing observation is that applying an ac-bias of a small frequency $f \ll f_p $ and sufficiently large amplitude changes the current-voltage characteristics ($I$-$V$ curve) of...
0407290v1
2005-07-29
Frustrated two-level impurities in two-dimensional antiferromagnets
Dynamical properties of the impurity spin-$\frac12$ in 2D and quasi-2D Heisenberg antiferromagnets (AFs) at $T\ge0$ are discussed. The specific case of an impurity coupled symmetrically to two neighboring host spins is considered. The specific feature of this problem is that the defect is degenerate (frustrated) being ...
0507704v2
2006-10-11
Miscibility in a degenerate fermionic mixture induced by linear coupling
We consider a one-dimensional mean-field-hydrodynamic model of a two-component degenerate Fermi gas in an external trap, each component representing a spin state of the same atom. We demonstrate that the interconversion between them (linear coupling), imposed by a resonant electromagnetic wave, transforms the immiscibl...
0610317v1
2002-03-12
Gravitational Waves from the Merger of Binary Neutron Stars in a Fully General Relativistic Simulation
We performed 3D numerical simulations of the merger of equal-mass binary neutron stars in full general relativity using a new large scale supercomputer. We take the typical grid size as (505,505,253) for (x,y,z) and the maximum grid size as (633,633,317). These grid numbers enable us to put the outer boundaries of the ...
0203037v1
2002-06-20
Gravitational Radiation Damping and the Three-Body Problem
A model of three-body motion is developed which includes the effects of gravitational radiation reaction. The radiation reaction due to the emission of gravitational waves is the only post-Newtonian effect that is included here. For simplicity, all of the motion is taken to be planar. Two of the masses are viewed as a ...
0206059v2
1997-10-15
Domain Walls Out of Equilibrium
We study the non-equilibrium dynamics of domain walls in real time for $\phi^4$ and Sine Gordon models in 1+1 dimensions in the dilute regime. The equation of motion for the collective coordinate is obtained by integrating out the meson excitations around the domain wall to one-loop order. The real-time non-equilibrium...
9710359v2
2000-07-18
Further studies on relic neutrino asymmetry generation I: the adiabatic Boltzmann limit, non-adiabatic evolution, and the classical harmonic oscillator analogue of the quantum kinetic equations
We demonstrate that the relic neutrino asymmetry evolution equation derived from the quantum kinetic equations (QKEs) reduces to the Boltzmann limit that is dependent only on the instantaneous neutrino number densities, in the adiabatic limit in conjunction with sufficient damping. An original physical and/or geometric...
0007185v3
2002-09-27
Lorentz-Invariant Non-Commutative QED
Lorentz-invariant non-commutative QED (NCQED) is constructed such that it should be a part of Lorentz-invariant non-commutative standard model (NCSM), a subject to be treated in later publications. Our NCSM is based on Connes' observation that the total fermion field in the standard model may be regarded as a bi-module...
0209234v2
2005-11-12
Elliptic Curves, Algebraic Geometry Approach in Gravity Theory and Some Applications in Theories with Extra Dimensions I
Motivated by the necessity to find exact solutions with the elliptic Weierstrass function of the Einstein's equations (see gr-qc/0105022),the present paper develops further the proposed approach in hep-th/0107231, concerning the s.c. cubic algebraic equation for effective parametrization. Obtaining an ''embedded'' sequ...
0511136v1
2002-04-11
High-fidelity teleportation of entanglements of running-wave field states
We describe a scheme for the teleportation of entanglements of zero- and one-photon running-wave field states. In addition to linear optical elements, Kerr nonlinearity is also employed so as to achieve a 100% probability of success in the ideal case. A comprehensive phenomenological treatment of errors in the domain o...
0204057v2
2007-04-25
Zakharov simulation study of spectral features of on-demand Langmuir turbulence in an inhomogeneous plasma
We have performed a simulation study of Langmuir turbulence in the Earth's ionosphere by means of a Zakharov model with parameters relevant for the F layer. The model includes dissipative terms to model collisions and Landau damping of the electrons and ions, and a linear density profile, which models the ionospheric p...
0704.3419v2
2007-06-04
Quantum theory of exciton-photon coupling in photonic crystal slabs with embedded quantum wells
A theoretical description of radiation-matter coupling for semiconductor-based photonic crystal slabs is presented, in which quantum wells are embedded within the waveguide core layer. A full quantum theory is developed, by quantizing both the electromagnetic field with a spatial modulation of the refractive index and ...
0706.0396v1
2007-06-05
Strong field effects on binary systems in Einstein-aether theory
"Einstein-aether" theory is a generally covariant theory of gravity containing a dynamical preferred frame. This article continues an examination of effects on the motion of binary pulsar systems in this theory, by incorporating effects due to strong fields in the vicinity of neutron star pulsars. These effects are inc...
0706.0704v2
2007-07-19
Structure formation in the presence of dark energy perturbations
We study non-linear structure formation in the presence of dark energy. The influence of dark energy on the growth of large-scale cosmological structures is exerted both through its background effect on the expansion rate, and through its perturbations as well. In order to compute the rate of formation of massive objec...
0707.2882v3
2007-07-25
Chromoelectric response functions for quark-gluon plasma
We determine the chromoelectric response of quark-gluon plasma (QGP) systematically within the framework of classical transport equations. The transport equations are set up in the phase space which includes the SU(3) group space corresponding to color (which is a dynamical degree of freedom), in addition to the positi...
0707.3697v3
2007-07-26
Coarse-Grained Finite-Temperature Theory for the Condensate in Optical Lattices
In this work, we derive a coarse-grained finite-temperature theory for a Bose condensate in a one-dimensional optical lattice, in addition to a confining harmonic trap potential. We start from a two-particle irreducible (2PI) effective action on the Schwinger-Keldysh closed-time contour path. In principle, this action ...
0707.3984v1
2007-10-04
Detailed Examination of Transport Coefficients in Cubic-Plus-Quartic Oscillator Chains
We examine the thermal conductivity and bulk viscosity of a one-dimensional (1D) chain of particles with cubic-plus-quartic interparticle potentials and no on-site potentials. This system is equivalent to the FPU-alpha beta system in a subset of its parameter space. We identify three distinct frequency regimes which we...
0710.1066v1
2007-10-16
A generalization of Snoek's law to ferromagnetic films and composites
The present paper establishes characteristics of the relative magnetic permeability spectrum $\mu$(f) of magnetic materials at microwave frequencies. The integral of the imaginary part of $\mu$(f) multiplied with the frequency f gives remarkable properties. A generalisation of Snoek's law consists in this quantity bein...
0710.2980v2
2007-11-28
Scalar Casimir Effect on a D-dimensional Einstein Static Universe
We compute the renormalised energy momentum tensor of a free scalar field coupled to gravity on an (n+1)-dimensional Einstein Static Universe (ESU), RxS^n, with arbitrary low energy effective operators (up to mass dimension n+1). A generic class of regulators is used, together with the Abel-Plana formula, leading to a ...
0711.4564v2
2008-01-04
Study of the preheating phase of chaotic inflation
Particle production and its effects on the inflaton field are investigated during the preheating phase of chaotic inflation using a model consisting of a massive scalar inflaton field coupled to N massless quantum scalar fields. The effects of spacetime curvature and interactions between the quantum fields are ignored....
0801.0730v3
2008-01-07
Collective plasmonic modes of metal nano-particles in two-dimensional periodic regular arrays
We investigate the collective plasmonic modes of metal nano-particles in periodic two-dimensional (2D) arrays within a point-dipole description. As an open system, the full-dynamic dispersion relations of the 2D arrays are obtained through an efficient method which gives an effective polarizability describing the colle...
0801.0906v1
2008-01-28
Doebner-Goldin Equation for Electrodynamic Particle. The Implied Applications
We set up the Maxwell's equations and the corresponding classical wave equations for the electromagnetic waves which together with the generating source, a traveling oscillatory charge of zero rest mass, comprise a particle traveling in the force field of an usual conservative potential and an additional frictional for...
0801.4279v2
2008-03-17
Fermionic Casimir effect in toroidally compactified de Sitter spacetime
We investigate the fermionic condensate and the vacuum expectation values of the energy-momentum tensor for a massive spinor field in de Sitter spacetime with spatial topology $\mathrm{R}^{p}\times (\mathrm{S}^{1})^{q}$. Both cases of periodicity and antiperiodicity conditions along the compactified dimensions are cons...
0803.2413v1
2008-03-27
Towards Understanding the Mass-Metallicity relation of Quasar Absorbers: Evidence for bimodality and consequences
One way to characterize and understand HI-selected galaxies is to study their metallicity properties. In particular, we show that the metallicity of absorbers is a bivariate function of the HI column density (NHI) and the MgII equivalent width (Wr(2796)). Thus, a selection upon Wr(2796) is not equivalent to a HI select...
0803.3944v3
2008-04-21
Precision calculations of the gravitational wave background spectrum from inflation
The spectrum of the gravitational wave background originating from quantum fluctuations during inflation is calculated numerically for various inflation models over a wide range of frequencies. We take into account four ingredients : the scalar field dynamics during inflation making no use of the slow-roll approximatio...
0804.3249v3
2008-04-21
Gravitational Instability in Radiation Pressure Dominated Backgrounds
I consider the physics of gravitational instabilities in the presence of dynamically important radiation pressure and gray radiative diffusion, governed by a constant opacity, kappa. For any non-zero radiation diffusion rate on an optically-thick scale, the medium is unstable unless the classical gas-only isothermal Je...
0804.3403v1
2008-04-26
Spatial Periodicity of Galaxy Number Counts, CMB Anisotropy, and SNIa Hubble Diagram Based on the Universe Accompanied by a Non-Minimally Coupled Scalar Field
We have succeeded in establishing a cosmological model with a non-minimally coupled scalar field $\phi$ that can account not only for the spatial periodicity or the {\it picket-fence structure} exhibited by the galaxy $N$-$z$ relation of the 2dF survey but also for the spatial power spectrum of the cosmic microwave bac...
0804.4240v1
2008-09-09
Turbulent Convection in Stellar Interiors. II. The Velocity Field
We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of the simulations (we relate temperature and density fluctuations via coefficients);...
0809.1625v2
2009-02-25
Propagating slow magnetoacoustic waves in coronal loops observed by Hinode/EIS
We present the first Hinode/EIS observations of 5 min quasi-periodic oscillations detected in a transition-region line (He II) and five coronal lines (Fe X, Fe XII, Fe XIII, Fe XIV, and Fe XV) at the footpoint of a coronal loop. The oscillations exist throughout the whole observation, characterized by a series of wave ...
0902.4480v1
2009-04-22
The Rotation of Janus and Epimetheus
Epimetheus, a small moon of Saturn, has a rotational libration (an oscillation about synchronous rotation) of 5.9 +- 1.2 degrees, placing Epimetheus in the company of Earth's Moon and Mars' Phobos as the only natural satellites for which forced rotational libration has been detected. The forced libration is caused by t...
0904.3515v2
2009-09-18
Stochastic Electron Acceleration in the TeV Supernova Remnant RX J1713.7-3946: The High-Energy Cut-off
In the leptonic scenario for TeV emission from a few well-observed shell-type TeV supernova remnants (STTSNRs), very weak magnetic fields are inferred. If fast-mode waves are produced efficiently in the shock downstream, we show that they are viable agents for acceleration of relativistic electrons inferred from the ob...
0909.3349v2
2009-10-10
The Electron Propagator in External Electromagnetic Fields in Lower Dimensions
We study the electron propagator in quantum electrodynamics in lower dimensions. In the case of free electrons, it is well known that the propagator in momentum space takes the simple form $S_F(p)=1/(\gamma\cdot p-m)$. In the presence of external electromagnetic fields, electron asymptotic states are no longer plane-wa...
0910.1881v1
2009-10-12
Effects on the two-point correlation function from the coupling of quintessence to dark matter
We investigate the effects of the nonminimal coupling between the scalar field dark energy (quintessence) and the dark matter on the two- point correlation function. It is well known that this coupling shifts the turnover scale as well as suppresses the amplitude of the matter power spectrum. However, these effects are...
0910.2175v2
2009-11-10
A Comparison between Two Simple Models of a Slug Flow in a Long Flexible Marine Riser
Slug flows are extremely interesting multiphase regime phenomena which frequently occur in flexible marine risers used by the petroleum industry in offshore environments and have both a liquid and gaseous phase. This paper describes two simple models of the slug flow regime by means of an equivalent monophase flow with...
0911.1873v1
2009-11-13
Two-resonator circuit QED: Dissipative Theory
We present a theoretical treatment for the dissipative two-resonator circuit quantum electrodynamics setup referred to as quantum switch. There, switchable coupling between two superconducting resonators is mediated by a superconducting qubit operating in the dispersive regime, where the qubit transition frequency is f...
0911.2657v4
2009-12-02
Eulerian and Lagrangian propagators for the adhesion model (Burgers dynamics)
Motivated by theoretical studies of gravitational clustering in the Universe, we compute propagators (response functions) in the adhesion model. This model, which is able to reproduce the skeleton of the cosmic web and includes nonlinear effects in both Eulerian and Lagrangian frameworks, also corresponds to the Burger...
0912.0356v1
2010-02-18
Average luminosity distance in inhomogeneous universes
Using numerical ray tracing, the paper studies how the average distance modulus in an inhomogeneous universe differs from its homogeneous counterpart. The averaging is over all directions from a fixed observer not over all possible observers (cosmic), thus it is more directly applicable to our observations. Unlike prev...
1002.3408v1
2010-05-25
Structural, static and dynamic magnetic properties of CoMnGe thin films on a sapphire a-plane substrate
Magnetic properties of CoMnGe thin films of different thicknesses (13, 34, 55, 83, 100 and 200 nm), grown by RF sputtering at 400{\deg}C on single crystal sapphire substrates, were studied using vibrating sample magnetometry (VSM) and conventional or micro-strip line (MS) ferromagnetic resonance (FMR). Their behavior i...
1005.4595v3
2010-09-28
Accurate interaction energies at DFT level by means of an efficient dispersion correction
This paper presents an approach for obtaining accurate interaction energies at the DFT level for systems where dispersion interactions are important. This approach combines Becke and Johnson's [J. Chem. Phys. 127, 154108 (2007)] method for the evaluation of dispersion energy corrections and a Hirshfeld method for parti...
1009.5631v1
2010-11-17
On the Critical Coupling for Kuramoto Oscillators
The Kuramoto model captures various synchronization phenomena in biological and man-made systems of coupled oscillators. It is well-known that there exists a critical coupling strength among the oscillators at which a phase transition from incoherency to synchronization occurs. This paper features four contributions. F...
1011.3878v2
2011-01-04
Universal Spin Transport in a Strongly Interacting Fermi Gas
Transport of fermions is central in many fields of physics. Electron transport runs modern technology, defining states of matter such as superconductors and insulators, and electron spin, rather than charge, is being explored as a new carrier of information [1]. Neutrino transport energizes supernova explosions followi...
1101.0780v1
2011-02-02
Galaxy N-z Relation and CMB Spectrum Based on Cosmological Model with Scalar Field Having Modified Potential Form
We have succeeded in establishing a cosmological model with a non-minimally coupled scalar field $\phi$ that can account not only for the spatial periodicity or the picket-fence structure exhibited by the galaxy $N$-$z$ relation of the 2dF survey, but also for the spatial power spectrum of the cosmic microwave backgrou...
1102.0341v1
2011-03-10
Compressive high-frequency waves riding on an Alfvén/ion-cyclotron wave in a multi-fluid plasma
In this paper, we study the weakly-compressive high-frequency plasma waves which are superposed on a large-amplitude Alfv\'en wave in a multi-fluid plasma consisting of protons, electrons, and alpha particles. For these waves, the plasma environment is inhomogenous due to the presence of the low-frequency Alfv\'en wave...
1103.2029v3
2011-03-17
Phonon Spectra, Nearest Neighbors, and Mechanical Stability of Disordered Colloidal Clusters with Attractive Interactions
We investigate the influence of morphology and size on the vibrational properties of disordered clusters of colloidal particles with attractive interactions. From measurements of displacement correlations between particles in each cluster, we extract vibrational properties of the corresponding "shadow" glassy cluster, ...
1103.3535v1
2011-06-15
Chiral symmetry breaking in QCD-like gauge theories with a confining propagator and dynamical gauge boson mass generation
We study chiral symmetry breaking in QCD-like gauge theories introducing a confining effective propagator, as proposed recently by Cornwall, and considering the effect of dynamical gauge boson mass generation. The effective confining propagator has the form $1/(k^2+m^2)^2$ and we study the bifurcation equation finding ...
1106.2860v3
2011-06-21
Symmetry and the macroscopic dynamics of antiferromagnetic materials in the presence of spin-polarized current
Antiferromagnetic (AFM) materials with zero or vanishingly small macroscopic magnetization are nowadays the constituent elements of spintronic devices. However, possibility to use them as active elements that show nontrivial controllable magnetic dynamics is still discussible. In the present paper we extend the theory ...
1106.4231v3
2011-07-05
Black-hole hair loss: learning about binary progenitors from ringdown signals
Perturbed Kerr black holes emit gravitational radiation, which (for the practical purposes of gravitational-wave astronomy) consists of a superposition of damped sinusoids termed quasi-normal modes. The frequencies and time-constants of the modes depend only on the mass and spin of the black hole - a consequence of the...
1107.0854v3
2011-08-01
Symplectic integrators with adaptive time steps
In recent decades, there have been many attempts to construct symplectic integrators with variable time steps, with rather disappointing results. In this paper we identify the causes for this lack of performance, and find that they fall into two categories. In the first, the time step is considered a function of time a...
1108.0322v1
2011-11-02
Self-consistent size and velocity distributions of collisional cascades
The standard theoretical treatment of collisional cascades derives a steady-state size distribution assuming a single constant velocity dispersion for all bodies regardless of size. Here we relax this assumption and solve self-consistently for the bodies' steady-state size and size-dependent velocity distributions. Spe...
1111.0667v1
2011-11-21
Ultrasoft Fermionic Modes at High Temperature
A possible collective fermionic excitation in the ultrasoft energy-momentum region is examined in Yukawa model with scalar coupling and quantum electrodynamics (QED) with g being coupling constant at extremely high temperature T where the fermion mass is negligible. We analytically sum up the ladder diagrams for the ve...
1111.5015v1
2011-12-05
Chiral symmetry breaking with a confining propagator and dynamically massive gluons
Chiral symmetry breaking in QCD is studied introducing a confining effective propagator, as proposed recently by Cornwall, and considering the effect of dynamically massive gluons. The effective confining propagator has the form $1/(k^2+m^2)^2$ and we study the bifurcation equation finding limits on the parameter $m$ b...
1112.0926v1
2012-01-03
Hydrodynamic model for electron-hole plasma in graphene
We propose a hydrodynamic model describing steady-state and dynamic electron and hole transport properties of graphene structures which accounts for the features of the electron and hole spectra. It is intended for electron-hole plasma in graphene characterized by high rate of intercarrier scattering compared to extern...
1201.0592v1
2012-07-02
Establishing micromagnetic parameters of ferromagnetic semiconductor (Ga,Mn)As
(Ga,Mn)As is at the forefront of research exploring the synergy of magnetism with the physics and technology of semiconductors, and has led to discoveries of new spin-dependent phenomena and functionalities applicable to a wide range of material systems. Its recognition and utility as an ideal model material for spintr...
1207.0310v1
2012-10-30
Transverse kink oscillations in the presence of twist
Magnetic twist is thought to play an important role in coronal loops. The effects of magnetic twist on stable magnetohydrodynamic (MHD) waves is poorly understood because they are seldom studied for relevant cases. The goal of this work is to study the fingerprints of magnetic twist on stable transverse kink oscillatio...
1210.8093v1
2013-02-07
Scalar and fermionic vacuum currents in de Sitter spacetime with compact dimensions
Vacuum expectation values (VEVs) of the current densities for charged scalar and Dirac spinor fields are investigated in (D+1)-dimensional de Sitter (dS) spacetime with toroidally compactified spatial dimensions. Along compact dimensions we impose quasiperiodicity conditions with arbitrary phases. In addition, the pres...
1302.1688v2
2013-04-17
Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria
Chlorosomes are the largest and most efficient natural light-harvesting antenna systems. They contain thousands of pigment molecules - bacteriochlorophylls (BChls)- that are organized into supramolecular aggregates and form a very efficient network for excitonic energy migration. Here, we present a theoretical study of...
1304.4902v2
2013-07-12
Study of Conduction Cooling Effects in Long Aspect Ratio Penning-Malmberg Micro-Traps
A first order perturbation with respect to velocity has been employed to find the frictional damping force imposed on a single moving charge due to a perturbative electric field, inside a long circular cylindrical trap. We find that the electric field provides a cooling effect, has a tensorial relationship with the vel...
1307.3357v1
2013-07-17
Analysis of the Taylor dissipation surrogate in forced isotropic turbulence
From the energy balance in wavenumber space expressed by the Lin equation, we derive a new form for the local Karman-Howarth equation for forced isotropic turbulence in real space. This equation is then cast into a dimensionless form, from which a combined analytical and numerical study leads us to deduce a new model f...
1307.4574v1
2013-07-26
The history force on a small particle in a linearly stratified fluid
The hydrodynamic force experienced by a small spherical particle undergoing an arbitrary time-dependent motion in a density-stratified fluid is investigated theoretically. The study is carried out under the Oberbeck-Boussinesq approximation, and in the limit of small Reynolds and small P\'eclet numbers. The force actin...
1307.6934v2
2013-08-27
Mechanical fluidity of fully suspended biological cells
Mechanical characteristics of single biological cells are used to identify and possibly leverage interesting differences among cells or cell populations. Fluidity---hysteresivity normalized to the extremes of an elastic solid or a viscous liquid---can be extracted from, and compared among, multiple rheological measurem...
1308.6004v1
2013-09-11
Numerical Boson Stars with a Single Killing Vector II: the D=3 Case
We complete the analysis of part I in this series (Ref. \cite{Stotyn:2013yka}) by numerically constructing boson stars in 2+1 dimensional Einstein gravity with negative cosmological constant, minimally coupled to a complex scalar field. These lower dimensional boson stars have strikingly different properties than their...
1309.2911v3
2013-11-13
Convergent perturbative nuclear effective field theory
We consider the nuclear effective field theory including pions in the two-nucleon sector in the S waves up to including the next-to-next-to-leading order (NNLO) terms according to the power counting suggested by the Wilsonian renormalization group analysis done in a previous paper. We treat only the leading contact int...
1311.3063v1
2013-11-14
Electric field gradient wave (EFGW) in iron-based superconductor Ba(0.6)K(0.4)Fe2As2 studied by Mössbauer spectroscopy
The optimally doped 122 iron-based superconductor Ba(0.6)K(0.4)Fe2As2 has been studied by 57Fe Moessbauer spectroscopy versus temperature ranging from 4.2 K till 300 K with particular attention paid to the superconducting transition around 38 K. The spectra do not contain magnetic components and they exhibit quasi-cont...
1311.3503v4
2013-12-24
Slow Light in Metamaterial Waveguides
Metamaterials, which are materials engineered to possess novel optical properties, have been increasingly studied. The ability to fabricate metamaterials has sparked an interest in determining possible applications. We investigate using a metamaterial for boundary engineering in waveguides. A metamaterial-clad cylind...
1312.6892v1