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47
2013-05-21
Characterization and Synthesis of Rayleigh Damped Elastodynamic Networks
We consider damped elastodynamic networks where the damping matrix is assumed to be a non-negative linear combination of the stiffness and mass matrices (also known as Rayleigh or proportional damping). We give here a characterization of the frequency response of such networks. We also answer the synthesis question for...
1305.4961v1
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
2015-02-26
Efficient modelling of particle collisions using a non-linear viscoelastic contact force
In this paper the normal collision of spherical particles is investigated. The particle interaction is modelled in a macroscopic way using the Hertzian contact force with additional linear damping. The goal of the work is to develop an efficient approximate solution of sufficient accuracy for this problem which can be ...
1502.07728v2
2018-12-10
H$_2$/HD molecular data for analysis of quasar spectra in search of varying constants
Absorption lines of H$_2$ and HD molecules observed at high redshift in the line of sight towards quasars are a test ground to search for variation of the proton-to-electron mass ratio $\mu$. For this purpose, results from astronomical observations are compared with a compilation of molecular data of the highest accura...
1812.03628v2
2019-12-24
Modified Drude model for small gold nanoparticles surface plasmon resonance based on the role of classical confinement
We study the effect of restoration force caused by the limited size of a small metallic nanoparticle (MNP) on its linear response to the electric field of incident light. In a semi-classical phenomenological Drude-like model for small MNP, we consider restoration force caused by the displacement of conduction electrons...
1912.11245v1
2022-01-03
Solid-like to Liquid-like Behavior of Cu Diffusion in Superionic Cu2X (X=S, Se): An Inelastic Neutron Scattering and Ab-Initio Molecular Dynamics Investigation
Cu2Se and Cu2S are excellent model systems of superionic conductors with large diffusion coefficients that have been reported to exhibit different solid-liquid-like Cu-ion diffusion. In this paper, we clarify the atomic dynamics of these compounds with temperature-dependent ab-initio molecular dynamics (AIMD) simulatio...
2201.00606v1
2024-02-22
Laser patterning of magnonic structure via local crystallization of Yittrium Iron Garnet
The fabrication and integration of high-quality structures of Yttrium Iron Garnet (YIG) is critical for magnonics.Films with excellent properties are obtained only on single crystal Gadolinium Gallium Garnet (GGG) substrates using high-temperature processes. The subsequent realization of magnonic structures via lithogr...
2402.14444v1
2024-03-07
The stochastic Ravine accelerated gradient method with general extrapolation coefficients
In a real Hilbert space domain setting, we study the convergence properties of the stochastic Ravine accelerated gradient method for convex differentiable optimization. We consider the general form of this algorithm where the extrapolation coefficients can vary with each iteration, and where the evaluation of the gradi...
2403.04860v2
2012-01-27
Full and Half Gilbert Tessellations with Rectangular Cells
We investigate the ray-length distributions for two different rectangular versions of Gilbert's tessellation. In the full rectangular version, lines extend either horizontally (with east- and west-growing rays) or vertically (north- and south-growing rays) from seed points which form a Poisson point process, each ray s...
1201.5780v1
2021-06-08
On numerical aspects of parameter identification for the Landau-Lifshitz-Gilbert equation in Magnetic Particle Imaging
The Landau-Lifshitz-Gilbert equation yields a mathematical model to describe the evolution of the magnetization of a magnetic material, particularly in response to an external applied magnetic field. It allows one to take into account various physical effects, such as the exchange within the magnetic material itself. I...
2106.07625v1
2021-01-28
Fluid-elastic coefficients in single phase cross flow: dimensional analysis, direct and indirect experimental methods
The importance of fluid-elastic forces in tube bundle vibrations can hardly be over-emphasized, in view of their damaging potential. In the last decades, advanced models for representing fluid-elastic coupling have therefore been developed by the community of the domain. Those models are nowadays embedded in the method...
2101.12021v1
2000-09-11
Numerical Studies on Locally Damped Structures
In the JLC/NLC X-band linear collider, it is essential to reduce the long-range dipole wakefields in the accelerator structure to prevent beam break up (BBU) and emittance degradation. The two methods of reducing the long-range wakefields are detuning and damping. Detuning reduces the wakefields rapidly as the dipole m...
0009039v1
2015-03-13
A one-step optimal energy decay formula for indirectly nonlinearly damped hyperbolic systems coupled by velocities
In this paper, we consider the energy decay of a damped hyperbolic system of wave-wave type which is coupled through the velocities. We are interested in the asymptotic properties of the solutions of this system in the case of indirect nonlinear damping, i.e. when only one equation is directly damped by a nonlinear dam...
1503.04126v1
2015-08-21
Radiative damping in wave guide based FMR measured via analysis of perpendicular standing spin waves in sputtered Permalloy films
The damping $\alpha$ of the spinwave resonances in 75 nm, 120 nm, and 200nm -thick Permalloy films is measured via vector-network-analyzer ferromagnetic-resonance (VNA-FMR) in the out-of-plane geometry. Inductive coupling between the sample and the waveguide leads to an additional radiative damping term. The radiative ...
1508.05265v1
2022-09-28
Tunable nonlinear damping in parametric regime
Nonlinear damping plays a significant role in several area of physics and it is becoming increasingly important to understand its underlying mechanism. However, microscopic origin of nonlinear damping is still a debatable topic. Here, we probe and report nonlinear damping in a highly tunable MoS2 nano mechanical drum r...
2209.14120v1
2005-11-07
The Effects of Alfven Waves and Radiation Pressure in Dusty Winds of Late-Type Stars. II. Dust-Cyclotron Damping
There are in the literature several theories to explain the mass loss in stellar winds. In particular, for late-type stars, some authors have proposed a wind model driven by an outward-directed flux of damped Alfven waves. The winds of these stars present great amounts of dust particles that, if charged, can give rise ...
0511192v2
2013-09-11
Initial versus tangent stiffness-based Rayleigh damping in inelastic time history seismic analyses
In the inelastic time history analyses of structures in seismic motion, part of the seismic energy that is imparted to the structure is absorbed by the inelastic structural model, and Rayleigh damping is commonly used in practice as an additional energy dissipation source. It has been acknowledged that Rayleigh damping...
1309.2741v1
2017-07-14
Damping of gravitational waves by matter
We develop a unified description, via the Boltzmann equation, of damping of gravitational waves by matter, incorporating collisions. We identify two physically distinct damping mechanisms -- collisional and Landau damping. We first consider damping in flat spacetime, and then generalize the results to allow for cosmolo...
1707.05192v2
2003-04-10
Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. VII. Relativistic calculations for O VI and O VII for UV and X-ray modeling
Aimed at ionization balance and spectral analysis of UV and X-ray sources, we present self-consistent sets of photoionization cross sections, recombination cross sections, and rate coefficients for Li-like O VI and He-like O VII. Relativistic fine structure is considered through the Breit-Pauli R-matrix (BPRM) method i...
0304204v1
2013-07-25
Relaxation of Bose-Einstein Condensates of Magnons in Magneto-Textural Traps in Superfluid $^3$He-B
In superfluid $^3$He-B externally pumped quantized spin-wave excitations or magnons spontaneously form a Bose-Einstein condensate in a 3-dimensional trap created with the order-parameter texture and a shallow minimum in the polarizing field. The condensation is manifested by coherent precession of the magnetization wit...
1307.6782v2
2014-01-07
Spectral parameter power series for polynomial pencils of Sturm-Liouville operators and Zakharov-Shabat systems
A spectral parameter power series (SPPS) representation for solutions of Sturm-Liouville equations of the form $$(pu')'+qu=u\sum_{k=1}^{N}\lambda^{k}r_{k}$$ is obtained. It allows one to write a general solution of the equation as a power series in terms of the spectral parameter $\lambda$. The coefficients of the seri...
1401.1520v1
2016-11-29
Derivation of a generalized Schrödinger equation from the theory of scale relativity
Using Nottale's theory of scale relativity relying on a fractal space-time, we derive a generalized Schr\"odinger equation taking into account the interaction of the system with the external environment. This equation describes the irreversible evolution of the system towards a static quantum state. We first interpret ...
1612.02323v1
2016-12-08
Robust identification of harmonic oscillator parameters using the adjoint Fokker-Planck equation
We present a model-based output-only method for identifying from time series the parameters governing the dynamics of stochastically forced oscillators. In this context, suitable models of the oscillator's damping and stiffness properties are postulated, guided by physical understanding of the oscillatory phenomena. Th...
1612.02579v1
2017-06-19
Derivation of a generalized Schrödinger equation for dark matter halos from the theory of scale relativity
Using Nottale's theory of scale relativity, we derive a generalized Schr\"odinger equation applying to dark matter halos. This equation involves a logarithmic nonlinearity associated with an effective temperature and a source of dissipation. Fundamentally, this wave equation arises from the nondifferentiability of the ...
1706.05900v2
2017-06-21
Spectral analysis and multigrid preconditioners for two-dimensional space-fractional diffusion equations
Fractional diffusion equations (FDEs) are a mathematical tool used for describing some special diffusion phenomena arising in many different applications like porous media and computational finance. In this paper, we focus on a two-dimensional space-FDE problem discretized by means of a second order finite difference s...
1706.06844v1
2018-02-03
Origin of the size-dependence of the equilibrium van der Waals binding between nanostructures
Nanostructures can be bound together at equilibrium by the van der Waals (vdW) effect, a small but ubiquitous many-body attraction that presents challenges to density functional theory. How does the binding energy depend upon the size or number of atoms in one of a pair of identical nanostructures? To answer this quest...
1802.00975v1
2018-04-12
System-size dependence of the viscous attenuation of anisotropic flow in p+Pb and Pb+Pb collisions at LHC energies
The elliptic and triangular flow coefficients ($\mathrm{v_n, \, n=2,3}$) measured in Pb+Pb ($\sqrt{s_{_{\rm NN}}} = 2.76$ TeV) and p+Pb ($\sqrt{s_{_{\rm NN}}} = 5.02$ TeV) collisions, are studied as a function of initial-state eccentricity ($\varepsilon_n$), and dimensionless size characterized by the cube root of the ...
1804.04618v3
2019-03-04
Role of geometrical cues in neuronal growth
Geometrical cues play an essential role in neuronal growth. Here, we quantify axonal growth on surfaces with controlled geometries and report a general stochastic approach that quantitatively describes the motion of growth cones. We show that axons display a strong directional alignment on micro-patterned surfaces when...
1903.01337v2
2019-05-07
On the reduction of required motions in the dynamic analysis using an optimization-based spectral matching
This study aims to show the efficiency of a proposed spectral matching technique for the reduction of required ground motions in the dynamic time history analysis. In this non-stationary spectral matching approach, unconstrained optimization is employed to adjust the signal to match a target spectrum. Adjustment factor...
1905.02394v4
2019-06-11
Anomalous diffusion for neuronal growth on surfaces with controlled geometries
Geometrical cues are known to play a very important role in neuronal growth and the formation of neuronal networks. Here, we present a detailed analysis of axonal growth and dynamics for neuronal cells cultured on patterned polydimethylsiloxane surfaces. We use fluorescence microscopy to image neurons, quantify their d...
1906.05679v1
2019-11-01
Free and forced wave propagation in beam lattice metamaterials with viscoelastic resonators
Beam lattice materials are characterized by a periodic microstructure realizing a geometrically regular pattern of elementary cells. In these microstructured materials, the dispersion properties governing the free dynamic propagation of elastic waves can be studied by formulating parametric lagrangian models and applyi...
1911.00455v1
2020-11-18
The theory of cosmic-ray scattering on pre-existing MHD modes meets data
We present a comprehensive study about the phenomenological implications of the theory describing Galactic cosmic-ray scattering onto magnetosonic and Alfv\'enic fluctuations in the $\mathrm{GeV} - \mathrm{PeV}$ domain. We compute a set of diffusion coefficients from first principles, for different values of the Alfv\'...
2011.09197v2
2021-02-03
On Geometric Fourier Particle In Cell Methods
In this article we describe a unifying framework for variational electromagnetic particle schemes of spectral type, and we propose a novel spectral Particle-In-Cell (PIC) scheme that preserves a discrete Hamiltonian structure. Our work is based on a new abstract variational derivation of particle schemes which builds o...
2102.02106v1
2021-02-10
Axion Quasiparticles for Axion Dark Matter Detection
It has been suggested that certain antiferromagnetic topological insulators contain axion quasiparticles (AQs), and that such materials could be used to detect axion dark matter (DM). The AQ is a longitudinal antiferromagnetic spin fluctuation coupled to the electromagnetic Chern-Simons term, which, in the presence of ...
2102.05366v2
2021-05-16
A Realizable Filtered Intrusive Polynomial Moment Method
Intrusive uncertainty quantification methods for hyperbolic problems exhibit spurious oscillations at shocks, which leads to a significant reduction of the overall approximation quality. Furthermore, a challenging task is to preserve hyperbolicity of the gPC moment system. An intrusive method which guarantees hyperboli...
2105.07473v1
2021-10-04
Probing three-state Potts nematic fluctuations by ultrasound attenuation
Motivated by recent studies of three-state Potts nematic states in magic-angle twisted bilayer graphene and doped-Bi$_2$Se$_3$, we analyze the impact of critical nematic fluctuations on the low energy properties of phonons. In this study we propose how to identify the three-state Potts nematic fluctuations by ultrasoun...
2110.01308v4
2022-11-09
Gravitational wave constraints on spatial covariant gravities
The direct discovery of gravitational waves (GWs) from the coalescence of compact binary components by the LIGO/Virgo/KAGRA Collaboration provides an unprecedented opportunity for exploring the underlying theory of gravity that drives the coalescence process in the strong and highly dynamical field regime of gravity. I...
2211.04711v2
2023-09-08
Minimum-dissipation model for large-eddy simulation in OpenFoam -A study on channel flow, periodic hills and flow over cylinder
The minimum-dissipation model is applied to turbulent channel flows up to $Re_\tau = 2000$, flow past a circular cylinder at $Re=3900$, and flow over periodic hills at $Re=10595$. Numerical simulations are performed in OpenFOAM which is based on finite volume methods for discretizing partial differential equations. We ...
2309.04415v1
2023-11-02
Minimum-dissipation model for large-eddy simulation using symmetry-preserving discretization in OpenFOAM
The minimum-dissipation model is applied to channel flow up to $Re_\tau = 2000$, flow past a circular cylinder at $Re=3900$, and flow over periodic hills at $Re=10595$. Numerical simulations were performed in OpenFOAM which is based on the finite volume methods. We used both symmetry-preserving and standard second-orde...
2311.01360v1
2023-11-03
Room-Temperature CsPbBr$_3$ Mixed Polaritons States
Light-matter interactions are known to lead to the formation of polariton states through what is called strong coupling, leading to the formation of two hybrid states usually tagged as Upper and Lower Polaritons. Here, we consider a similar interaction between excitons and photons in the realm of strong interactions, w...
2311.02252v2
1998-05-22
Analytic description of the r-mode instability in uniform density stars
We present an analytic description of the $r$-mode instability in newly-born neutron stars, using the approximation of uniform density. Our computation is consistently accurate to second order in the angular velocity of the star. We obtain formulae for the growth-time of the instability due to gravitational-wave emissi...
9805297v1
2004-06-21
Resolution and accuracy of resonances in R-matrix cross sections
We investigate the effect of resonances in photoionization and recombination cross sections computed using the R-matrix method. Photoionization and recombination rates derived from high-resolution cross sections for oxygen ions are compared with earlier works with less resolution and accuracy, such as in the widely use...
0406472v1
2006-07-01
Exotic bulk viscosity and its influence on neutron star r-modes
We investigate the effect of exotic matter in particular, hyperon matter on neutron star properties such as equation of state (EoS), mass-radius relationship and bulk viscosity. Here we construct equations of state within the framework of a relativistic field theoretical model. As hyperons are produced abundantly in de...
0607005v2
2006-07-11
Collisional Particle Disks
We present a new, simple, fast algorithm to numerically evolve disks of inelastically colliding particles surrounding a central star. Our algorithm adds negligible computational cost to the fastest existing collisionless N-body codes, and can be used to simulate, for the first time, the interaction of planets with disk...
0607241v1
2007-01-19
Revised Primordial Helium Abundance Based on New Atomic Data
We have derived a primordial helium abundance of Yp = 0.2477 +- 0.0029, based on new atomic physics computations of the recombination coefficients of He I and of the collisional excitation of the H I Balmer lines together with observations and photoionization models of metal-poor extragalactic H II regions. The new ato...
0701580v2
1995-07-03
Fundamental steps of group velocity for slow surface polariton under the quantum hall effect conditions
A new type of collective electromagnetic excitations, namely surface polaritons (SP) --- in a 2D electronic layer in a high magnetic field under Quantum Hall Effect (QHE) conditions is predicted. We have found the spectrum, damping, and polarization of the SP in a wide range of frequencies $\omega$ and wavevectors $\bf...
9507001v1
1996-04-26
Macroscopic Quantum Tunneling of a Fluxon in a Long Josephson Junction
Macroscopic quantum tunneling (MQT) for a single fluxon moving along a long Josephson junction is studied theoretically. To introduce a fluxon-pinning force, we consider inhomogeneities made by modifying thickness of an insulating layer locally. Two different situations are studied: one is the quantum tunneling from a ...
9604160v2
1997-09-03
Shaping an ultracold atomic soliton in a travelling wave laser beam
An ultracold wave packet of bosonic atoms loaded into a travelling laser wave may form a many-atom soliton.This is disturbed by a homogeneous force field, for example by the inevitable gravitation. The wave packet is accelerated and therefore the laser frequency appears to be chirped in the rest frame of the atoms. We ...
9709038v1
1997-10-20
Row-switched states in two-dimensional underdamped Josephson junction arrays
When magnetic flux moves across layered or granular superconductor structures, the passage of vortices can take place along channels which develop finite voltage, while the rest of the material remains in the zero-voltage state. We present analytical studies of an example of such mixed dynamics: the row-switched (RS) s...
9710204v1
1998-04-21
Inelastic collapse of a randomly forced particle
We consider a randomly forced particle moving in a finite region, which rebounds inelastically with coefficient of restitution r on collision with the boundaries. We show that there is a transition at a critical value of r, r_c\equiv e^{-\pi/\sqrt{3}}, above which the dynamics is ergodic but beneath which the particle ...
9804229v1
1999-02-25
Mobility of Bloch Walls via the Collective Coordinate Method
We have studied the problem of the dissipative motion of Bloch walls considering a totally anisotropic one dimensional spin chain in the presence of a magnetic field. Using the so-called "collective coordinate method" we construct an effective Hamiltonian for the Bloch wall coupled to the magnetic excitations of the sy...
9902330v1
2004-02-21
Effect of backing thickness on determination of the phase in neutron reflectometry by variation of backing
The determination of density profiles with knowing the phase information of complex reflection coefficient for neutron specularly reflected from a film, yields unique results. Recently it has been shown that the phase can be determined by using controlled variation of the scattering length density of the fronting (inci...
0402541v1
2004-03-23
Phase transitions induced by noise cross-correlations
A general approach to consider spatially extended stochastic systems with correlations between additive and multiplicative noises subject to nonlinear damping is developed. Within modified cumulant expansion method, we derive an effective Fokker-Planck equation whose stationary solutions describe a character of ordered...
0403583v2
2004-12-13
Field-tuned quantum critical point of antiferromagnetic metals
A magnetic field applied to a three-dimensional antiferromagnetic metal can destroy the long-range order and thereby induce a quantum critical point. Such field-induced quantum critical behavior is the focus of many recent experiments. We investigate theoretically the quantum critical behavior of clean antiferromagneti...
0412284v1
2005-10-13
Statistical-mechanical description of classical test-particle dynamics in the presence of an external force field: modelling noise and damping from first principles
Aiming to establish a rigorous link between macroscopic random motion (described e.g. by Langevin-type theories) and microscopic dynamics, we have undertaken a kinetic-theoretical study of the dynamics of a classical test-particle weakly coupled to a large heat-bath in thermal equilibrium. Both subsystems are subject t...
0510359v2
2006-04-13
Dissipative magneto-optic solitons
Magneto-optic behaviour is a specific, non-reciprocal example of gyrotropic behaviour. When coupled to photo-induced Faraday rotation it is possible to discriminate this effect from the background of other nonlinear effects Non-reciprocal behaviour is characteristic of artificial gyrotropy and can be used in optical is...
0604355v1
2006-12-07
Dynamics of a metastable state nonlinearly coupled to a heat bath driven by an external noise
Based on a system-reservoir model, where the system is nonlinearly coupled to a heat bath and the heat bath is modulated by an external stationary Gaussian noise, we derive the generalized Langevin equation with space dependent friction and multiplicative noise and construct the corresponding Fokker-Planck equation, va...
0612193v2
2002-12-03
d-Dimensional Black Hole Entropy Spectrum from Quasi-Normal Modes
Starting from recent observations\cite{hod,dreyer1} about quasi-normal modes, we use semi-classical arguments to derive the Bekenstein-Hawking entropy spectrum for $d$-dimensional spherically symmetric black holes. We find that the entropy spectrum is equally spaced: $S_{BH}=k \ln(m_0)n$, where $m_0$ is a fixed integer...
0212014v2
2003-12-17
A Post-Newtonian diagnostic of quasi-equilibrium binary configurations of compact objects
Using equations of motion accurate to the third post-Newtonian (3PN) order (O(v/c)^6 beyond Newtonian gravity), we derive expressions for the total energy E and angular momentum J of the orbits of compact binary systems (black holes or neutron stars) for arbitrary orbital eccentricity. We also incorporate finite-size c...
0312082v3
1994-07-29
Standard Model Baryogenesis
Simply on CP arguments, we argue against a Standard Model explanation of baryogenesis via the charge transport mechanism. A CP-asymmetry is found in the reflection coefficients of quarks hitting the electroweak phase boundary created during a first order phase transition. The problem is analyzed both in an academic zer...
9407403v2
2000-02-25
A New Source for Electroweak Baryogenesis in the MSSM
One of the most experimentally testable explanations for the origin of the baryon asymmetry of the universe is that it was created during the electroweak phase transition, in the minimal supersymmetric standard model. Previous efforts have focused on the current for the difference of the two Higgsino fields, $H_1-H_2$,...
0002272v2
2000-06-15
Development of the electroweak phase transition and baryogenesis
We investigate the evolution of the electroweak phase transition, using a one-Higgs effective potential that can be regarded as an approximation for the Minimal Supersymmetric Standard Model. The phase transition occurs in a small interval around a temperature T_t below the critical one. We calculate this temperature a...
0006177v2
2001-03-09
Transport theory for a two-flavor color superconductor
QCD with two light quark flavors at high baryonic density and low temperature is a color superconductor. The diquark condensate partially breaks the SU(3) gauge symmetry down to an SU(2) subgroup. We study thermal fluctuations of the superconductor for temperatures below the gap. These are described by a simple transpo...
0103092v2
2002-05-18
Perturbative and non-perturbative aspects of the non-abelian Boltzmann-Langevin equation
We study the Boltzmann-Langevin equation which describes the dynamics of hot Yang-Mills fields with typical momenta of order of the magnetic screening scale g^2 T. It is transformed into a path integral and Feynman rules are obtained. We find that the leading log Langevin equation can be systematically improved in a we...
0205202v2
2003-07-05
Hard Loops, Soft Loops, and High Density Effective Field Theory
We study several issues related to the use of effective field theories in QCD at large baryon density. We show that the power counting is complicated by the appearance of two scales inside loop integrals. Hard dense loops involve the large scale $\mu^2$ and lead to phenomena such as screening and damping at the scale $...
0307074v1
2004-02-04
Infrared Behavior of High-Temperature QCD
The damping rate \gamma_t(p) of on-shell transverse gluons with ultrasoft momentum p is calculated in the context of next-to-leading-order hard-thermal-loop-summed perturbation of high-temperature QCD. It is obtained in an expansion to second order in p. The first coefficient is recovered but that of order p^2 is found...
0402041v1
2004-06-04
Shear Viscosity in a CFL Quark Star
We compute the mean free path and shear viscosity in the color-flavor locked (CFL) phase of dense quark matter at low temperature T, when the contributions of mesons, quarks and gluons to the transport coefficients are Boltzmann suppressed. CFL quark matter displays superfluid properties, and transport phenomena in suc...
0406058v3
2005-01-11
Fermionic dispersion relations in ultradegenerate relativistic plasmas beyond leading logarithmic order
We determine the dispersion relations of fermionic quasiparticles in ultradegenerate plasmas by a complete evaluation of the on-shell hard-dense-loop-resummed one-loop fermion self energy for momenta of the order of the Fermi momentum and above. In the case of zero temperature, we calculate the nonanalytic terms in the...
0501089v2
1994-07-19
On the Macroscopic Limit of Nuclear Dissipation
The Landau-Vlasov equation is applied to a slab of width $L$. This geometry is introduced to simulate somehow the finiteness of real nuclei but to allow for analytical solutions, nevertheless. We focus on the damping of low frequency surface modes and discuss their friction coefficient. For this quantity we study the m...
9407029v1
1997-12-08
Amplitude equations and pattern selection in Faraday waves
A nonlinear theory of pattern selection in parametric surface waves (Faraday waves) is presented that is not restricted to small viscous dissipation. By using a multiple scale asymptotic expansion near threshold, a standing wave amplitude equation is derived from the governing equations. The amplitude equation is of gr...
9712003v1
2003-04-17
Linear theory of nonlocal transport in a magnetized plasma
A system of nonlocal electron-transport equations for small perturbations in a magnetized plasma is derived using the systematic closure procedure of V. Yu. Bychenkov et al., Phys. Rev. Lett. 75, 4405 (1995). Solution to the linearized kinetic equation with a Landau collision operator is obtained in the diffusive appro...
0304063v1
2005-10-20
Probing liquid surface waves, liquid properties and liquid films with light diffraction
Surface waves on liquids act as a dynamical phase grating for incident light. In this article, we revisit the classical method of probing such waves (wavelengths of the order of mm) as well as inherent properties of liquids and liquid films on liquids, using optical diffraction. A combination of simulation and experime...
0510184v2
2002-04-30
Laser-driven atom moving in a multimode cavity: strong enhancement of cavity-cooling efficiency
Cavity-mediated cooling of the center--of--mass motion of a transversally, coherently pumped atom along the axis of a high--Q cavity is studied. The internal dynamics of the atomic dipole strongly coupled to the cavity field is treated by a non-perturbative quantum mechanical model, while the effect of the cavity on th...
0204170v1
2004-07-06
Field quantization in inhomogeneous absorptive dielectrics
The quantization of the electromagnetic field in a three-dimensional inhomogeneous dielectric medium with losses is carried out in the framework of a damped-polariton model with an arbitrary spatial dependence of its parameters. The equations of motion for the canonical variables are solved explicitly by means of Lapla...
0407045v1
2006-09-15
Photoionization Broadening of the 1S-2S Transition in a Beam of Atomic Hydrogen
We consider the excitation dynamics of the two-photon \sts transition in a beam of atomic hydrogen by 243 nm laser radiation. Specifically, we study the impact of ionization damping on the transition line shape, caused by the possibility of ionization of the 2S level by the same laser field. Using a Monte-Carlo simulat...
0609114v1
2006-09-21
ε-convertibility of entangled states and extension of Schmidt rank in infinite-dimensional systems
By introducing the concept of $\epsilon$-convertibility, we extend Nielsen's and Vidal's theorems to the entanglement transformation of infinite-dimensional systems. Using an infinite-dimensional version of Vidal's theorem we derive a new stochastic-LOCC (SLOCC) monotone which can be considered as an extension of the S...
0609167v4
2007-04-20
Determining factors behind the PageRank log-log plot
We study the relation between PageRank and other parameters of information networks such as in-degree, out-degree, and the fraction of dangling nodes. We model this relation through a stochastic equation inspired by the original definition of PageRank. Further, we use the theory of regular variation to prove that PageR...
0704.2694v1
2007-05-15
Electrical excitation of shock and soliton-like waves in two-dimensional electron channels
We study electrical excitation of nonlinear plasma waves in heterostructures with two-dimensional electron channels and with split gates, and the propagation of these waves using hydrodynamic equations for electron transport coupled with two-dimensional Poisson equation for self-consistent electric potential. The term ...
0705.2111v1
2007-07-27
Oscillatory D'yakonov-Perel' spin dynamics in two dimensional electron gases
Optical pump-probe measurements of spin-dynamics at temperatures down to 1.5K are described for a series of (001)-oriented GaAs/AlGaAs quantum well samples containing high mobility two-dimensional electron gases (2DEGs). For well widths ranging from 5 nm to 20 nm and 2DEG sheet densities from 1.75x1011cm-2 to 3.5x1011c...
0707.4180v1
2008-01-07
Field Theoretic Description of Ultrarelativistic Electron-Positron Plasmas
Ultrarelativistic electron-positron plasmas can be produced in high-intensity laser fields and play a role in various astrophysical situations. Their properties can be calculated using QED at finite temperature. Here we will use perturbative QED at finite temperature for calculating various important properties, such a...
0801.0956v2
2008-05-20
Probability of metastable configurations in spherical three-dimensional Yukawa crystals
Recently the occurrence probabilities of ground- and metastable states of three-dimensional Yukawa clusters with 27 and 31 particles have been analyzed in dusty plasma experiments [Block et al., Physics of Plasmas 15, 040701 (2008)]. There it was found that, in many cases, the ground state appeared substantially less f...
0805.3016v1
2008-05-29
Dispersion enhancement and damping by buoyancy driven flows in 2D networks of capillaries
The influence of a small relative density difference on the displacement of two miscible liquids is studied experimentally in transparent 2D networks of micro channels. Both stable displacements in which the denser fluid enters at the bottom of the cell and displaces the lighter one and unstable displacements in which ...
0805.4564v1
2008-06-12
Vortex dynamics in trapped Bose-Einstein condensate
We perform numerical simulations of vortex motion in a trapped Bose-Einstein condensate by solving the two-dimensional Gross-Pitaevskii Equation in the presence of a simple phenomenological model of interaction between the condensate and the finite temperature thermal cloud. At zero temperature, the trajectories of a s...
0806.2077v2
2008-06-12
Diversity-induced resonance in a system of globally coupled linear oscillators
The purpose of this paper to analyze in some detail the arguably simplest case of diversity-induced reseonance: that of a system of globally-coupled linear oscillators subjected to a periodic forcing. Diversity appears as the parameters characterizing each oscillator, namely its mass, internal frequency and damping coe...
0806.2106v1
2008-08-05
From Equilibrium to Transport Properties of Strongly Correlated Fermi Liquids
We summarize recent results regarding the equilibrium and non-equilibrium behavior of cold dilute atomic gases in the limit in which the two body scattering length a goes to infinity. In this limit the system is described by a Galilean invariant (non-relativistic) conformal field theory. We discuss the low energy effec...
0808.0734v1
2008-09-09
What can we learn from electromagnetic plasmas about the quark-gluon plasma?
Ultra-relativistic electromagnetic plasmas can be used for improving our understanding of the quark-gluon plasma. In the weakly coupled regime both plasmas can be described by transport theoretical and quantum field theoretical methods leading to similar results for the plasma properties (dielectric tensor, dispersion ...
0809.1507v1
2008-10-06
Ultrarelativistic Electron-Positron Plasma
Ultrarelativistic electron-positron plasmas can be produced in high-intensity laser fields and play a role in various astrophysical situations. Their properties can be calculated using QED at finite temperature. Here we will use perturbative QED at finite temperature for calculating various important properties, such a...
0810.0909v1
2009-01-27
A simple, low-cost, data-logging pendulum built from a computer mouse
Lessons and homework problems involving a pendulum are often a big part of introductory physics classes and laboratory courses from high school to undergraduate levels. Although laboratory equipment for pendulum experiments is commercially available, it is often expensive and may not be affordable for teachers on fixed...
0901.4319v1
2009-02-18
Frequency dependence of viscous and viscoelastic dissipation in coated micro-cantilevers from noise measurement
We measure the mechanical thermal noise of soft silicon atomic force microscopy cantilevers. Using an interferometric setup, we have a resolution down to 1E-14 m/rtHz on a wide spectral range (3 Hz to 1E5 Hz). The low frequency behavior depends dramatically on the presence of a reflective coating: almost flat spectrums...
0902.3134v2
2009-03-10
Phonon-phonon interactions and phonon damping in carbon nanotubes
We formulate and study the effective low-energy quantum theory of interacting long-wavelength acoustic phonons in carbon nanotubes within the framework of continuum elasticity theory. A general and analytical derivation of all three- and four-phonon processes is provided, and the relevant coupling constants are determi...
0903.1771v2
2009-03-30
Breit-Wigner resonances and the quasinormal modes of anti-de Sitter black holes
The purpose of this short communication is to show that the theory of Breit-Wigner resonances can be used as an efficient numerical tool to compute black hole quasinormal modes. For illustration we focus on the Schwarzschild anti-de Sitter (SAdS) spacetime. The resonance method is better suited to small SAdS black hole...
0903.5311v1
2009-08-21
Aspects of warm-flat directions
Considering the mechanism of dissipative slow-roll that has been used in warm inflation scenario, we show that dissipation may alter usual cosmological scenarios associated with SUSY-flat directions. We mainly consider SUSY-flat directions that have strong interactions with non-flat directions and may cause strong diss...
0908.3059v4
2009-10-19
Friction force on slow charges moving over supported graphene
We provide a theoretical model that describes the dielectric coupling of a 2D layer of graphene, represented by a polarization function in the Random Phase Approximation, and a semi-infinite 3D substrate, represented by a surface response function in a non-local formulation. We concentrate on the role of the dynamic re...
0910.3586v1
2009-11-15
Effect of three-body loss on itinerant ferromagnetism in an atomic Fermi gas
A recent experiment has provided the first evidence for itinerant ferromagnetism in an ultracold atomic gas of fermions with repulsive interactions. However, the gas in this regime is also subject to significant three-body loss. We adopt an extended Hertz-Millis theory to account for the effect of loss on the transitio...
0911.2839v1
2009-12-18
Gravitational Instability in Presence of Bulk Viscosity: the Jeans Mass and the Quasi-Isotropic Solution
This paper focuses on the analysis of the gravitational instability in presence of bulk viscosity both in Newtonian regime and in the fully-relativistic approach. The standard Jeans Mechanism and the Quasi-Isotropic Solution are treated expressing the bulk-viscosity coefficient $\zeta$ as a power-law of the fluid energ...
0912.3641v1
2010-01-14
A Theoretical Closure for Turbulent Flows Near Walls
This paper proposes a simple new closure principle for turbulent shear flows. The turbulent flow field is divided into an outer and an inner region. The inner region is made up of a log-law region and a wall layer. The wall layer is viewed in terms of the well known inrush-sweep-burst sequence observed since 1967. It i...
1001.2353v1
2010-02-23
Bulk viscosity in hyperonic star and r-mode instability
We consider a rotating neutron star with the presence of hyperons in its core, using an equation of state in an effective chiral model within the relativistic mean field approximation. We calculate the hyperonic bulk viscosity coefficient due to nonleptonic weak interactions. By estimating the damping timescales of the...
1002.4253v1
2010-03-03
Phonon lineshapes in atom-surface scattering
Phonon lineshapes in atom-surface scattering are obtained from a simple stochastic model based on the so-called Caldeira-Leggett Hamiltonian. In this single-bath model, the excited phonon resulting from a creation or annihilation event is coupled to a thermal bath consisting of an infinite number of harmonic oscillator...
1003.0790v2
2010-03-30
Superfluid hyperon bulk viscosity and the r-mode instability of rotating neutron stars
In order to establish whether the unstable r-modes in a rotating neutron star provide a detectable source of gravitational waves, we need to understand the details of the many dissipative processes that tend to counteract the instability. It has been established that the bulk viscosity due to exotic particles, like hyp...
1003.5849v1
2010-05-07
r-modes in low temperature colour-flavour-locked superconducting quark star
We present the first multi-fluid analysis of a dense neutron star core with a deconfined colour-flavour-locked superconducting quark component. Accounting only for the condensate and (finite temperature) phonons, we make progress by taking over results for superfluid $^4$He. The resultant two-fluid model accounts for a...
1005.1163v1