publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2007-01-12 | Electron spin quantum beats in positively charged quantum dots: nuclear field effects | We have studied the electron spin coherence in an ensemble of positively
charged InAs/GaAs quantum dots. In a transverse magnetic field, we show that
two main contributions must be taken into account to explain the damping of the
circular polarization oscillations. The first one is due to the nuclear field
fluctuations... | 0701284v2 |
2007-02-05 | Verification of stable operation of rapid single flux quantum devices with selective dissipation | It has been suggested that Rapid Single Flux Quantum (RSFQ) devices could be
used as the classical interface of superconducting qubit systems. One problem
is that the interface acts as a dissipative environment for a qubit. Recently
ways to modify the RSFQ damping to reduce the dissipation have been introduced.
One of ... | 0702104v1 |
2007-02-21 | RPAE versus RPA for the Tomonaga model with quadratic energy dispersion | Recently the damping of the collective charge (and spin) modes of interacting
fermions in one spatial dimension was studied. It results from the nonlinear
correction to the energy dispersion in the vicinity of the Fermi points. To
investigate the damping one has to replace the random phase approximation (RPA)
bare bubb... | 0702488v2 |
2007-03-01 | Spin dynamics across the superfluid-insulator transition of spinful bosons | Bosons with non-zero spin exhibit a rich variety of superfluid and insulating
phases. Most phases support coherent spin oscillations, which have been the
focus of numerous recent experiments. These spin oscillations are Rabi
oscillations between discrete levels deep in the insulator, while deep in the
superfluid they c... | 0703011v2 |
2007-03-21 | Edge magnetoplasmons in a partially screened two-dimensional electron gas on a helium surface | We report a study of edge magnetoplasmons in a partially-screened system of
electrons on a helium surface. We compare experimental results with theories of
the frequency, damping, and penetration-depth dependence on magnetic field,
temperature-dependent damping, and the dependence of the frequency on
screening. We show... | 0703558v1 |
1997-02-12 | On the problem of semiinfinite beam oscillation with internal damping | We study the Cauchy problem for the equation of the form $$ \ddot{u}(t) +
(\aa A + B)\dot{u}(t) + (A+G)u(t) = 0,\tag* $$ where $A$, $B$, and $G$ are \o s
in a Hilbert space $\Cal H$ with $A$ selfadjoint, $\sigma(A)=[0,\infty)$,
$B\ge0$ bounded, and $G$ symmetric and $A$-subordinate in a certain sense.
Spectral properti... | 9702007v1 |
1994-04-14 | Decoherence, Correlation, and Unstable Quantum States in Semiclassical Cosmology | It is demonstrated that almost any S-matrix of quantum field theory in curved
spaces posses an infinite set of complex poles (or branch cuts). These poles
can be transformed into complex eigenvalues, the corresponding eigenvectors
being Gamow vectors. All this formalism, which is heuristic in ordinary Hilbert
space, be... | 9404028v1 |
1994-09-27 | Effects of weak self-interactions in a relativistic plasma on cosmological perturbations | The exact solutions for linear cosmological perturbations which have been
obtained for collisionless relativistic matter within thermal field theory are
extended to a self-interacting case. The two-loop contributions of scalar
$\lambda\phi^4$ theory to the thermal graviton self-energy are evaluated, which
give the $O(\... | 9409055v2 |
1995-03-07 | ON THE OSCILLATION SPECTRA OF ULTRA COMPACT STARS | Quasinormal modes of ultra compact stars with uniform energy density have
been calculated. For less compact stars, there is only one very slowly damped
polar mode (corresponding to the Kelvin f-mode) for each spherical harmonic
index $l$. Further long-lived modes become possible for a sufficiently compact
star (roughly... | 9503012v1 |
1998-02-13 | Radiation Damping in FRW Space-times with Different Topologies | We study the role played by the compactness and the degree of connectedness
in the time evolution of the energy of a radiating system in the
Friedmann-Robertson-Walker (FRW) space-times whose $t=const $ spacelike
sections are the Euclidean 3-manifold ${\cal R}^3$ and six topologically
non-equivalent flat orientable com... | 9802031v1 |
1998-05-06 | Damping of Gravitational Waves and Density Perturbations in the Early Universe | Since the discovery of the large angular scale anisotropies in the microwave
background radiation, the behaviour of cosmological perturbations (especially,
density perturbations and gravitational waves) has been of great interest. In
this study, after a detailed and rigorous treatment of the behaviour of
gravitational ... | 9805016v1 |
1998-11-11 | Late-Time Evolution of Realistic Rotating Collapse and The No-Hair Theorem | We study analytically the asymptotic late-time evolution of realistic
rotating collapse. This is done by considering the asymptotic late-time
solutions of Teukolsky's master equation, which governs the evolution of
gravitational, electromagnetic, neutrino and scalar perturbations fields on
Kerr spacetimes. In accordanc... | 9811032v2 |
1999-09-22 | Vorticity affects the stability of neutron stars | The spin rate \Omega of neutron stars at a given temperature T is constrained
by the interplay between gravitational-radiation instabilities and viscous
damping. Navier-Stokes theory has been used to calculate the viscous damping
timescales and produce a stability curve for r-modes in the (\Omega,T) plane.
In Navier-St... | 9909073v2 |
2000-02-02 | Active controls in interferometric detectors of gravitational waves: inertial damping of the VIRGO superattenuator | The operation of an interferometer for gravitational waves detection requires
sophisticated feedback controls in many parts of the apparatus. The aim of this
lecture is to introduce the types of problems to be faced in this line of
research. The attention is focused on the "inertial damping" of the test mass
suspension... | 0002006v2 |
2000-08-09 | Gravitational Wave Damping of Neutron Star Wobble | We calculate the effect of gravitational wave (gw) back-reaction on realistic
neutron stars (NS's) undergoing torque-free precession. By `realistic' we mean
that the NS is treated as a mostly-fluid body with an elastic crust, as opposed
to a rigid body. We find that gw's damp NS wobble on a timescale tau_{theta}
approx... | 0008021v1 |
2000-11-30 | Tests of strong-field gravity and gravitational radiation damping in binary-pulsar systems | This talk reviews the constraints imposed by binary-pulsar data on gravity
theories, and notably on "scalar-tensor" theories which are the most natural
alternatives to general relativity. Because neutron stars have a strong
gravitational binding energy, binary-pulsar tests are qualitatively different
from solar-system ... | 0011114v1 |
2001-07-17 | Properties of r modes in rotating magnetic neutron stars. I. Kinematic Secular Effects and Magnetic Evolution Equations | The instability of r-mode oscillations in rapidly rotating neutron stars has
attracted attention as a potential mechanism for producing high frequency,
almost periodic gravitational waves. The analyses carried so far have shown the
existence of these modes and have considered damping by shear and bulk
viscosity. Howeve... | 0107061v1 |
2004-01-13 | Highly Damped Quasinormal Modes of Kerr Black Holes: A Complete Numerical Investigation | We compute for the first time very highly damped quasinormal modes of the
(rotating) Kerr black hole. Our numerical technique is based on a decoupling of
the radial and angular equations, performed using a large-frequency expansion
for the angular separation constant_{s}A_{l m}. This allows us to go much
further in ove... | 0401052v1 |
2006-12-07 | Improved calculation of relic gravitational waves | In this paper, we improve the calculation of the relic gravitational waves
(RGW) in two aspects: First, we investigate the transfer function after
considering the redshift-suppression effect, the accelerating expansion effect,
the damping effect of free-streaming relativistic particles, and the damping
effect of cosmic... | 0612041v3 |
2007-01-16 | Influence of Lorentz violation on Dirac quasinormal modes in the Schwarzschild black hole spacetime | Using the third-order WKB approximation and monodromy methods, we investigate
the influence of Lorentz violating coefficient $b$ (associated with a special
axial-vector $b_{\mu}$ field) on Dirac quasinormal modes in the Schwarzschild
black hole spacetime. At fundamental overtone, the real part decreases linearly
as the... | 0701089v1 |
2007-03-29 | Constraint Damping in First-Order Evolution Systems for Numerical Relativity | A new constraint suppressing formulation of the Einstein evolution equations
is presented, generalizing the five-parameter first-order system due to Kidder,
Scheel and Teukolsky (KST). The auxiliary fields, introduced to make the KST
system first-order, are given modified evolution equations designed to drive
constrain... | 0703145v1 |
1992-06-21 | Gauge Dependence of the Resummed Thermal Gluon Self Energy | The gauge dependence of the hot gluon self energy is examined in the context
of Pisarski's method for resumming hard thermal loops. Braaten and Pisarski
have used the Ward identities satisfied by the hard corrections to the n-point
functions to argue the gauge fixing independence of the leading order resummed
QCD plasm... | 9206239v1 |
1993-05-07 | Thermal quark production in pure glue and quark gluon plasmas | We calculate production rates for massless $(u,d)$ and massive $(s,c,b)$
quarks in pure glue and quark gluon plasmas to leading order in the strong
coupling constant $g$. The leading contribution comes from gluon decay into
$q\bar q$ pairs, using a thermal gluon propagator with finite thermal mass and
damping rate. The... | 9305227v1 |
1994-01-21 | Transport Properties of Quark and Gluon Plasmas | The kinetic properties of relativistic quark-gluon and electron-photon
plasmas are described in the weak coupling limit. The troublesome Rutherford
divergence at small scattering angles is screened by Debye screening for the
longitudinal or electric part of the interactions. The transverse or magnetic
part of the inter... | 9401300v1 |
1994-04-20 | Electroweak Baryogenesis and Standard Model CP Violation | We analyze the mechanism of electroweak baryogenesis proposed by Farrar and
Shaposhnikov in which the phase of the CKM mixing matrix is the only source of
$CP$ violation. This mechanism is based on a phase separation of baryons via
the scattering of quasiparticles by the wall of an expanding bubble produced at
the elec... | 9404302v1 |
1994-06-11 | Standard Model CP-violation and Baryon asymmetry Part II: Finite Temperature | We consider the scattering of quasi-particles off the boundary created during
a first order electroweak phase transition. Spatial coherence is lost due to
the quasi-quark damping rate, and we show that reflection on the boundary is
suppressed, even at tree-level. Simply on CP considerations, we argue against
electrowea... | 9406289v2 |
1995-01-03 | High temperature QCD and QED with unstable excitations | We consider the partition functions of QCD and QED at high temperature
assuming small coupling constants, and present arguments in favor of an
improved perturbative expansion in terms of unstable excitations. Our effective
propagators are derived from spectral functions with a constant width. These
spectral functions d... | 9501203v1 |
1995-12-12 | Bubble Collisions and Defect Formation in a Damping Environment | Within the context of a first-order phase transition in the early Universe,
we study the collision process for vacuum bubbles expanding in a plasma. The
effects of the plasma are simulated by introducing a damping term in the
equations of motion for a $U(1)$ global field. We find that Lorentz-contracted
spherically sym... | 9512290v1 |
1996-09-02 | The quasiparticle structure of hot gauge theories | The study of the ultrarelativistic plasmas in perturbation theory is plagued
with infrared divergences which are not eliminated by the screening
corrections. They affect, in particular, the computation of the lifetime of the
elementary excitations, thus casting doubt on the validity of the quasiparticle
picture. We sho... | 9609225v1 |
1996-10-18 | Finiteness of Hot Classical Scalar Field Theory and the Plasmon Damping Rate | We investigate the renormalizability of the classical $\phi^4$ theory at
finite temperature. We calculate the time-dependent two point function to two
loop order and show that it can be rendered finite by the counterterms of the
classical static theory. As an application the classical plasmon damping rate
is found to b... | 9610415v2 |
1996-12-30 | Defect Formation in First Order Phase Transitions with Damping | Within the context of first order phase transitions in the early universe, we
study the influence of a coupling between the (global U(1)) scalar driving the
transition and the rest of the matter content of the theory. The effect of the
coupling on the scalar is simulated by introducing a damping term in its
equations o... | 9612487v1 |
1997-07-28 | Plasmon properties in classical lattice gauge theory | In order to investigate the features of the classical approximation at high
temperatures for real time correlation functions, the plasmon frequencies and
damping rates were recently computed numerically in the SU(2)+Higgs model and
in the pure SU(2) theory. We compare the lattice results with leading order
hard thermal... | 9707489v2 |
1998-09-11 | Dynamical renormalization group resummation of finite temperature infrared divergences | We introduce the method of dynamical renormalization group to study
relaxation and damping out of equilibrium directly in real time and applied it
to the study of infrared divergences in scalar QED. This method allows a
consistent resummation of infrared effects associated with the exchange of
quasistatic transverse ph... | 9809346v2 |
1999-02-12 | Beyond HTL: The Classical Kinetic Theory of Landau Damping for Selfinteracting Scalar Fields in the Broken Phase | The effective theory of low frequency fluctuations of selfinteracting scalar
fields is constructed in the broken symmetry phase. The theory resulting from
integrating fluctuations with frequencies much above the spontanously generated
mass scale $(p_0>>M)$ is found to be local. Non-local dynamics, especially
Landau dam... | 9902331v1 |
2000-04-05 | A consistent nonperturbative approach to thermal damping-rates | We propose a nonperturbative scheme for the calculation of thermal
damping-rates using exact renormalization group (RG)-equations. Special
emphasis is put on the thermal RG where first results for the rate were given
in M. Pietroni, Phys. Rev. Lett. 81 (1998), 2424. We point out that in order to
obtain a complete resul... | 0004039v2 |
2000-06-09 | Random values of the cosmological constant | One way that an anthropic selection mechanism may be manifest in a physical
theory involves multiple domains in the universe with different values of the
physical parameters. If this mechanism is to be relevant for understanding the
small observed value of the cosmological constant, it may involve a mechanism
by which ... | 0006088v2 |
2000-07-07 | Finite pion width effects on the rho--meson | We study the influence of the finite damping width of pions on the in-medium
properties of the rho-meson in an interacting meson gas model at finite
temperature. Using vector dominance also implications on the resulting dilepton
spectra from the decay of the rho-meson are presented. A set of coupled Dyson
equations wit... | 0007070v3 |
2000-08-31 | New Regime for Dense String Networks | We uncover a new transient regime that reconciles the apparent inconsistency
of the Martins Shellard one scale damped string evolution model with the
initial conditions predicted by the Kibble mechanism for string formation in a
second order phase transition. This regime carries (in a short cosmic time
$\sim .1 t_c$) t... | 0008330v1 |
2001-01-25 | The Fermion Boson Interaction Within the Linear Sigma Model at Finite Temperature | We reinvestigate the interaction of massless fermions with massless bosons at
finite temperature. Specifically, we calculate the self-energy of massless
fermions due the interaction with massless bosons at high temperature, which is
the region where thermal effects are maximal. The calculations are concentrated
in the ... | 0101283v3 |
2001-11-02 | Quark Number Susceptibility in Hard Thermal Loop Approximation | We calculate the quark number susceptibility in the deconfined phase of QCD
using the hard thermal loop (HTL) approximation for the quark propagator. This
improved perturbation theory takes into account important medium effects such
as thermal quark masses and Landau damping in the quark-gluon plasma. We
explicitly sho... | 0111022v4 |
2001-12-29 | Damped $\sin(β-α)$ of Higgs couplings and the lightest Higgs production at $γγ$ colliders in MSSM | In the decoupling limit, $M^2_{A^0} \gg M^2_Z$, the heavy CP-even, CP-odd and
charged Higgs boson masses are nearly degenerate, $\sin(\beta-\alpha)$
approaches 1, and the lightest CP-even Higgs boson almost displays the same
properties as the Standard Model Higgs boson. But the stop and sbottom sector
can change this p... | 0112356v1 |
2004-05-31 | Gauge dependence of the fermion quasiparticle poles in hot gauge theories | The gauge dependence of the complex fermion quasiparticle poles corresponding
to soft collective excitations is studied in hot gauge theories at one-loop
order and next-to-leading order in the high-temperature expansion, with a view
towards going beyond the leading order hard thermal loops and resummations
thereof. We ... | 0406002v2 |
2004-11-09 | Numerical investigation of friction in inflaton equations of motion | The equation of motion for the expectation value of a scalar quantum field
does not have the local form that is commonly assumed in studies of
inflationary cosmology. We have recently argued that the true, temporally
non-local equation of motion does not possess a time-derivative expansion and
that the conversion of in... | 0411130v1 |
2006-03-03 | Damping of supernova neutrino transitions in stochastic shock-wave density profiles | Supernova neutrino flavor transitions during the shock wave propagation are
known to encode relevant information not only about the matter density profile
but also about unknown neutrino properties, such as the mass hierarchy (normal
or inverted) and the mixing angle theta_13. While previous studies have
focussed on "d... | 0603033v2 |
2006-08-11 | Constraining SuperWIMPy and Warm Subhalos with Future Submillilensing | We propose to observe QSO-galaxy strong lens systems to give a new constraint
on the damping scale of the initial fluctuations. We find that the future
observation of submilliarc scale astrometric shifts of the multiple lensed
images of QSOs would find \sim 10^{(3-9)} M_{\odot} subhalos inside the
macrolens halo. The s... | 0608126v2 |
2006-11-15 | Time-to-Space Conversion in Neutrino Oscillations | We study the neutrino oscillation problem in the framework of the wave packet
formalism. The neutrino state is described by a packet located initially in a
region S (source) and detected in another region D at a distance R from S. We
examine how the oscillation probability as a function of variable R can be
derived fro... | 0611202v1 |
1991-09-26 | The Damping of Energetic Gluons and Quarks in High-Temperature QCD | When a gluon or a quark is sent through the hot QCD plasma it can be absorbed
into the ambient heat bath and so can acquire an effective lifetime. At high
temperatures and for weak couplings the inverse lifetime, or damping rate, for
energetic quarks and transverse gluons, (those whose momenta satisfy $|\p| \gg
gT$) is... | 9109051v1 |
1998-09-11 | Damping and reaction rates and wave function renormalization of fermions in hot gauge theories | We examine the relation between the damping rate of a chiral fermion mode
propagating in a hot plasma and the rate at which the mode approaches
equilibrium. We show how these two quantities, obtained from the imaginary part
of the fermion self-energy, are equal when the reaction rate is defined using
the appropriate wa... | 9809083v2 |
2003-12-28 | A mechanism of the large-scale damping in the CMB anisotropy | We present a mechanism through which a certain class of short-distance cutoff
affects the CMB anisotropies at large angular scales. Our analysis is performed
in two steps. The first is given in an intuitive way, using the property of the
inflationary universe that quantum fluctuations of an inflaton field become
classi... | 0312298v7 |
2005-03-03 | Scalar field perturbations of the Schwarzschild black hole in the Gödel Universe | We investigate the scalar field perturbations of the 4+1-dimensional
Schwarzschild black hole immersed in a G\"{o}del Universe, described by the
Gimon-Hashimoto solution.This may model the influence of the possible rotation
of the Universe upon the radiative processes near a black hole. In the regime
when the scale par... | 0503029v2 |
2005-06-28 | Liouville Decoherence in a Model of Flavour Oscillations in the presence of Dark Energy | We study in some detail the master equation, and its solution in a simplified
case modelling flavour oscillations of a two-level system, stemming from the
Liouville-string approach to quantum space time foam. In this framework we
discuss the appearance of diffusion terms and decoherence due to the
interaction of low-en... | 0506242v1 |
2005-08-25 | The Dynamics of Small Instanton Phase Transitions | The small instanton transition of a five-brane colliding with one end of the
S1/Z2 interval in heterotic M-theory is discussed, with emphasis on the
transition moduli, their potential function and the associated non-perturbative
superpotential. Using numerical methods, the equations of motion of these
moduli coupled to... | 0508190v2 |
2006-11-21 | Renormalization group study of damping in nonequilibrium field theory | In this paper we shall study whether dissipation in a $\lambda\phi^{4}$ may
be described, in the long wavelength, low frequency limit, with a simple Ohmic
term $\kappa\dot{\phi}$, as it is usually done, for example, in studies of
defect formation in nonequilibrium phase transitions. We shall obtain an
effective theory ... | 0611222v1 |
2006-02-16 | Exit from a basin of attraction for stochastic weakly damped nonlinear Schrödinger equations | We consider weakly damped nonlinear Schr\"odinger equations perturbed by a
noise of small amplitude. The small noise is either complex and of additive
type or real and of multiplicative type. It is white in time and colored in
space. Zero is an asymptotically stable equilibrium point of the deterministic
equations. We ... | 0602350v1 |
2006-04-07 | Quasi-periodic attractors, Borel summability and the Bryuno condition for strongly dissipative systems | We consider a class of ordinary differential equations describing
one-dimensional analytic systems with a quasi-periodic forcing term and in the
presence of damping. In the limit of large damping, under some generic
non-degeneracy condition on the force, there are quasi-periodic solutions which
have the same frequency ... | 0604162v1 |
2006-06-30 | Uniform attractors for non-autonomous wave equations with nonlinear damping | We consider dynamical behavior of non-autonomous wave-type evolutionary
equations with nonlinear damping, critical nonlinearity, and time-dependent
external forcing which is translation bounded but not translation compact
(i.e., external forcing is not necessarily time-periodic, quasi-periodic or
almost periodic). A su... | 0606776v1 |
2001-04-17 | Scattering and radiation damping in gyroscopic Lorentz electrodynamic | Relativistic massive Lorentz electrodynamics (LED) is studied in a
``gyroscopic setup'' where the electromagnetic fields and the particle spin are
the only dynamical degrees of freedom.
A rigorous proof of the global existence and uniqueness of the dynamics is
given for essentially the whole range of field strengths ... | 0104023v2 |
2002-06-18 | Hamiltonian and Linear-Space Structure for Damped Oscillators: I. General Theory | The phase space of $N$ damped linear oscillators is endowed with a bilinear
map under which the evolution operator is symmetric. This analog of
self-adjointness allows properties familiar from conservative systems to be
recovered, e.g., eigenvectors are "orthogonal" under the bilinear map and obey
sum rules, initial-va... | 0206026v2 |
2002-06-17 | Hamiltonian and Linear-Space Structure for Damped Oscillators: II. Critical Points | The eigenvector expansion developed in the preceding paper for a system of
damped linear oscillators is extended to critical points, where eigenvectors
merge and the time-evolution operator $H$ assumes a Jordan-block structure. The
representation of the bilinear map is obtained in this basis. Perturbations
$\epsilon\De... | 0206027v2 |
2002-06-22 | Yank and Hooke's constant group theoretically | We study the second central extension of the (1+1) Aristotle Lie.We find that
the first central extension admit four orbits on the dual of second central
extension of the (1+1) Aristotle Lie group.The generic orbit is characterised
by a Hooke's constant k and a yank y.If the physics of the orbit is studied
with respect... | 0206038v1 |
2004-02-24 | Classical harmonic oscillator with Dirac-like parameters and possible applications | We obtain a class of parametric oscillation modes that we call K-modes with
damping and absorption that are connected to the classical harmonic oscillator
modes through the "supersymmetric" one-dimensional matrix procedure similar to
relationships of the same type between Dirac and Schroedinger equations in
particle ph... | 0402065v2 |
2000-02-22 | Front motion for phase transitions in systems with memory | We consider the Allen-Cahn equations with memory (a partial
integro-differential convolution equation). The prototype kernels are
exponentially decreasing functions of time and they reduce the
integrodifferential equation to a hyperbolic one, the damped Klein-Gordon
equation. By means of a formal asymptotic analysis we... | 0002039v1 |
2002-03-01 | Excitation of travelling multibreathers in anharmonic chains | We study the dynamics of the "externally" forced and damped Fermi-Pasta-Ulam
(FPU) 1D lattice. The forcing has the spatial symmetry of the Fourier mode with
wavenumber p and oscillates sinusoidally in time with the frequency omega. When
omega is in the phonon band, the p-mode becomes modulationally unstable above a
cri... | 0203002v1 |
2003-01-15 | Resonant triad dynamics in weakly damped Faraday waves with two-frequency forcing | Many of the interesting patterns seen in recent multi-frequency Faraday
experiments can be understood on the basis of three-wave interactions (resonant
triads). In this paper we consider two-frequency forcing and focus on a
resonant triad that occurs near the bicritical point where two pattern-forming
modes with distin... | 0301015v1 |
2003-03-21 | Global well-posedness and multi-tone solutions of a class of nonlinear nonlocal cochlear models in hearing | We study a class of nonlinear nonlocal cochlear models of the transmission
line type, describing the motion of basilar membrane (BM) in the cochlea. They
are damped dispersive partial differential equations (PDEs) driven by time
dependent boundary forcing due to the input sounds. The global well-posedness
in time follo... | 0303048v1 |
2004-05-11 | Analytical approach to soliton ratchets in asymmetric potentials | We use soliton perturbation theory and collective coordinate ansatz to
investigate the mechanism of soliton ratchets in a driven and damped asymmetric
double sine-Gordon equation. We show that, at the second order of the
perturbation scheme, the soliton internal vibrations can couple {\it
effectively}, in presence of d... | 0405023v1 |
2005-02-16 | Controlling soliton explosions | We investigate the dynamics of solitons in generalized Klein-Gordon equations
in the presence of nonlinear damping and spatiotemporal perturbations. We will
present different mechanisms for soliton explosions. We show (both analytically
and numerically) that some space-dependent perturbations or nonlinear damping
can m... | 0502033v1 |
2005-07-22 | Global existence in infinite lattices of nonlinear oscillators: The Discrete Klein-Gordon equation | Pointing out the difference between the Discrete Nonlinear Schr\"odinger
equation with the classical power law nonlinearity-for which solutions exist
globally, independently of the sign and the degree of the nonlinearity, the
size of the initial data and the dimension of the lattice-we prove either
global existence or ... | 0507044v5 |
1992-12-14 | Poisson and Porter-Thomas Fluctuations in off-Yrast Rotational Transitions | Fluctuations associated with stretched E2 transitions from high spin levels
in nuclei around $^{168}$Yb are investigated by a cranked shell model extended
to include residual two-body interactions. It is found that the gamma-ray
energies behave like random variables and the energy spectra show the Poisson
fluctuation, ... | 9212006v1 |
1993-11-25 | Microscopic analysis of two-body correlations in light nuclei | Within a nonperturbative dynamical two-body approach - based on coupled
equations of motion for the one-body density matrix and the two-body
correlation function - we study the distribution of occupation numbers in a
correlated system close to the groundstate, the relaxation of single-particle
excitations and the dampi... | 9311031v1 |
1997-03-26 | A self-consistent treatment of damped motion for stable and unstable collective modes | We address the dynamics of damped collective modes in terms of first and
second moments. The modes are introduced in a self-consistent fashion with the
help of a suitable application of linear response theory. Quantum effects in
the fluctuations are governed by diffusion coefficients D_{\mu\nu}. The latter
are obtained... | 9703056v1 |
1997-04-24 | A Simple Mode on a Highly Excited Background: Collective Strength and Damping in the Continuum | Simple states, such as isobaric analog states or giant resonances, embedded
into continuum are typical for mesoscopic many-body quantum systems. Due to the
coupling to compound states in the same energy range, a simple mode acquires a
damping width ("internal" dynamics). When studied experimentally with the aid
of vari... | 9704055v1 |
1998-02-27 | New collective mode due to collisional coupling | Starting from a nonmarkovian conserving relaxation time approximation for
collisions we derive coupled dispersion relations for asymmetric nuclear
matter. The isovector and isoscalar modes are coupled due to asymmetric nuclear
meanfield acting on neutrons and protons differently. A further coupling is
observed by colli... | 9802083v1 |
1998-10-12 | Response function beyond mean field of neutron-rich nuclei | The damping of single-particle and collective motion in exotic isotopes is a
new topic and its study may shed light on basic problems of nuclear dynamics.
For instance, it is known that nuclear structure calculations are not able, as
a rule, to account completely for the empirical single-particle damping. In
this contr... | 9810033v1 |
1999-04-14 | Scaling Analysis of Fluctuating Strength Function | We propose a new method to analyze fluctuations in the strength function
phenomena in highly excited nuclei. Extending the method of multifractal
analysis to the cases where the strength fluctuations do not obey power scaling
laws, we introduce a new measure of fluctuation, called the local scaling
dimension, which cha... | 9904037v1 |
1999-07-07 | Pair creation: back-reactions and damping | We solve the quantum Vlasov equation for fermions and bosons, incorporating
spontaneous pair creation in the presence of back-reactions and collisions.
Pair creation is initiated by an external impulse field and the source term is
non-Markovian. A simultaneous solution of Maxwell's equation in the presence of
feedback ... | 9907027v1 |
2000-10-23 | Barrier penetration and rotational damping of thermally excited superdeformed nuclei | We construct a microscopic model of thermally excited superdeformed states
that describes both the barrier penetration mechanism, leading to the decay-out
transitions to normal deformed states, and the rotational damping causing
fragmentation of rotational E2 transitions. We describe the barrier penetration
by means of... | 0010074v1 |
1996-02-22 | Stability of Travelling Waves for a Damped Hyperbolic Equation | We consider a nonlinear damped hyperbolic equation in $\real^n$, $1 \le n \le
4$, depending on a positive parameter $\epsilon$. If we set $\epsilon=0$, this
equation reduces to the well-known Kolmogorov-Petrovski-Piskunov equation. We
remark that, after a change of variables, this hyperbolic equation has the same
famil... | 9602004v1 |
1998-09-18 | Stability of Propagating Fronts in Damped Hyperbolic Equations | We consider the damped hyperbolic equation in one space dimension $\epsilon
u_{tt} + u_t = u_{xx} + F(u)$, where $\epsilon$ is a positive, not necessarily
small parameter. We assume that $F(0)=F(1)=0$ and that $F$ is concave on the
interval $[0,1]$. Under these assumptions, our equation has a continuous family
of monot... | 9809007v1 |
1999-05-28 | Existence threshold for the ac-driven damped nonlinear Schrödinger solitons | It has been known for some time that solitons of the externally driven,
damped nonlinear Schr\"odinger equation can only exist if the driver's
strength, $h$, exceeds approximately $(2/ \pi) \gamma$, where $\gamma$ is the
dissipation coefficient. Although this perturbative result was expected to be
correct only to the l... | 9906001v1 |
1996-10-01 | Exact time evolution and master equations for the damped harmonic oscillator | Using the exact path integral solution for the damped harmonic oscillator it
is shown that in general there does not exist an exact dissipative Liouville
operator describing the dynamics of the oscillator for arbitrary initial bath
preparations. Exact non-stationary Liouville operators can be found only for
particular ... | 9610001v1 |
1999-01-09 | Cluster ionization via two-plasmon excitation | We calculate the two-photon ionization of clusters for photon energies near
the surface plasmon resonance. The results are expressed in terms of the
ionization rate of a double plasmon excitation, which is calculated
perturbatively. For the conditions of the experiment by Schlipper et al., we
find an ionization rate of... | 9901008v1 |
2000-08-01 | Rectangular Waveguide HOM Couplers for a TESLA Superstructure | Some modifications of a Rectangular Waveguide HOM couplers for TESLA
superstructure have been investigated. These RWG HOM couplers are to be
installed between the cavities of the superstructure and also at the both ends
of it. We investigated a RWG HOM coupler attached to the beam pipe through the
slots orientated alon... | 0008001v1 |
2000-08-14 | Design of a 3 GHz Accelerator Structure for the CLIC Test Facility (CTF 3) Drive Beam | For the CLIC two-beam scheme, a high-current, long-pulse drive beam is
required for RF power generation. Taking advantage of the 3 GHz klystrons
available at the LEP injector once LEP stops, a 180 MeV electron accelerator is
being constructed for a nominal beam current of 3.5 A and 1.5 microsecond pulse
length. The hig... | 0008052v1 |
2000-08-17 | Superconducting Superstructure for the TESLA Collider: New Results | A new cavity-chain layout has been proposed for the main linac of the TESLA
linear collider. This superstructure-layout is based upon four 7-cell
superconducting standing-wave cavities, coupled by short beam pipes. The main
advantages of the superstructure are an increase in the active accelerating
length in TESLA and ... | 0008104v1 |
2000-08-20 | An Investigation of Optimised Frequency Distributions for Damping Wakefields in X-Band Linacs for the NLC | In the NLC (Next Linear Collider) small misalignments in each of the
individual accelerator structures (or the accelerator cells) will give rise to
wakefields which kick the beam from its electrical axis. This wakefield can
cause BBU (Beam Break Up) or at the very least it will dilute the emittance of
the beam. Several... | 0008202v2 |
2001-04-14 | Parameters for a 30 GeV Undulator Test Facility in the FFTB/LCLS | The parameters for a 30 GeV test beam are outlined for use with an undulator
in the FFTB tunnel where the LCLS will eventually be housed. It is proposed to
use the SLAC linac and damping rings in their present mode of operation for PEP
II injection, where 30 GeV beams are also delivered at 10 Hz to the FFTB. High
peak ... | 0104045v1 |
2001-10-05 | Characterization of a Low Frequency Power Spectral Density f^(-gamma) in a Threshold Model | his study investigates the modifications of the thermal spectrum, at low
frequency, induced by an external damping on a system in heat contact with
internal fluctuating impurities. Those impurities can move among locations and
their oscillations are associated with a loss function depending on the model.
The fluctuatio... | 0110019v1 |
2002-05-13 | Damping of electromagnetic waves in low-collision electron-ion plasmas | Using previously developed method of two-dimensional Laplace transform we
obtain the characteristic equations k(\omega) for electromagnetic waves in
low-collision fully ionized plasma of a plane geometry. We apply here a new,
different from the one used in our previous paper, iteration procedure of
taking into account ... | 0205035v2 |
2002-06-01 | Intrabeam scattering analysis of measurements at KEK's ATF damping ring | We derive a simple relation for estimating the relative emittance growth in x
and y due to intrabeam scattering (IBS) in electron storage rings. We show that
IBS calculations for the ATF damping ring, when using the formalism of
Bjorken-Mtingwa, a modified formalism of Piwinski (where eta squared divided by
beta has be... | 0206003v1 |
2002-08-24 | Wakefield Band Partitioning In Linac Structures | In the NLC project multiple bunches of electrons and positrons will be
accelerated initially to a centre of mass of 500 GeV and later to 1 TeV or
more. In the process of accelerating 192 bunches within a pulse train,
wakefields are excited which kick the trailing bunches off axis and can cause
luminosity dilution and B... | 0208086v1 |
2003-01-30 | Calculation of the Coherent Synchrotron Radiation Impedance from a Wiggler | Most studies of Coherent Synchrotron Radiation (CSR) have only considered the
radiation from independent dipole magnets. However, in the damping rings of
future linear colliders, a large fraction of the radiation power will be
emitted in damping wigglers. In this paper, the longitudinal wakefield and
impedance due to C... | 0301073v1 |
2003-10-02 | Damping factors for the gap-tooth scheme | An important class of problems exhibits macroscopically smooth behaviour in
space and time, while only a microscopic evolution law is known. For such
time-dependent multi-scale problems, the gap-tooth scheme has recently been
proposed. The scheme approximates the evolution of an unavailable (in closed
form) macroscopic... | 0310014v1 |
2004-07-31 | Propagation of optical excitations by dipolar interactions in metal nanoparticle chains | Dispersion relations for dipolar modes propagating along a chain of metal
nanoparticles are calculated by solving the full Maxwell equations, including
radiation damping. The nanoparticles are treated as point dipoles, which means
the results are valid only for a/d <= 1/3, where a is the particle radius and d
the spaci... | 0408003v2 |
2004-08-22 | Tacoma Bridge Failure-- a Physical Model | The cause of the collapse of the Tacoma Narrows Bridge has been a topic of
much debate and confusion since the day it fell. Many mischaracterizations of
the observed phenomena have limited the widespread understanding of the
problem. Nevertheless, there has always been an abundance of evidence in favour
of a negative d... | 0408101v1 |
2004-08-30 | Short waves and cyclotron losses in the relativistic gyrokinetic theory | Radiation damping of the motion of charged particles in relativistic,
optically thin plasmas is described within the framework of the covariant
gyrokinetic theory. It involves description of the collisionless
single-particle dynamics as well as the Vlasov and Maxwell equations both
written in the covariant formulation.... | 0408128v1 |
2004-11-02 | Supersymmetric free-damped oscillators: Adaptive observer estimation of the Riccati parameter | A supersymmetric class of free damped oscillators with three parameters has
been obtained in 1998 by Rosu and Reyes through the factorization of the Newton
equation. The supplementary parameter is the integration constant of the
general Riccati solution. The estimation of the latter parameter is performed
here by emplo... | 0411019v2 |
2004-11-05 | Wave-kinetic description of nonlinear photons | The nonlinear interaction, due to quantum electrodynamical (QED) effects,
between photons is investigated using a wave-kinetic description. Starting from
a coherent wave description, we use the Wigner transform technique to obtain a
set of wave-kinetic equations, the so called Wigner-Moyal equations. These
equations ar... | 0411058v1 |
2004-12-17 | Optimal Determination of the Equilibrium Displacement of a Damped Harmonic Oscillator in the Presence of Thermal Noise | Using a matched filter technique, we derive the minimum variance, unbiased
estimator for the equilibrium displacement of a damped harmonic oscillator in
thermal equilibrium when interactions with the thermal bath are the leading
source of noise. We compare the variance in this optimal estimator with the
variance in oth... | 0412102v1 |
2006-01-13 | Atomic collider into dual-isotope magneto-optical trap | When two of three pairs of the Gaussian laser beams of a traditional MOT are
misaligned in the racetrack configuration the effective coordinate-dependent
vortex force do arise. Then an atom is accelerated by this vortex force until
its velocity not balanced by the damping force. This situation may produce a
stable ring... | 0601097v1 |
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