publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2003-11-06 | Perturbation-induced radiation by the Ablowitz-Ladik soliton | An efficient formalism is elaborated to analytically describe dynamics of the
Ablowitz-Ladik soliton in the presence of perturbations. This formalism is
based on using the Riemann-Hilbert problem and provides the means of
calculating evolution of the discrete soliton parameters, as well as shape
distortion and perturba... | 0311010v1 |
2004-04-26 | Nonlinear stability of oscillatory wave fronts in chains of coupled oscillators | We present a stability theory for kink propagation in chains of coupled
oscillators and a new algorithm for the numerical study of kink dynamics. The
numerical solutions are computed using an equivalent integral equation instead
of a system of differential equations. This avoids uncertainty about the impact
of artifici... | 0404044v1 |
2004-10-15 | Comment on "Soliton ratchets induced by excitation of internal modes" | Very recently Willis et al. [Phys. Rev. E {\bf 69}, 056612 (2004)] have used
a collective variable theory to explain the appearance of a nonzero energy
current in an ac driven, damped sine-Gordon equation. In this comment, we prove
rigorously that the time-averaged energy current in an ac driven nonlinear
Klein-Gordon ... | 0410021v1 |
2005-02-25 | A kinetic approach to Bose-Einstein condensates: self-phase modulation and Bogoliubov oscillations | A kinetic approach to the Bose-Einstein condensates (BECs) is proposed, based
on the Wigner-Moyal equation (WME). In the quasi-classical limit, the WME
reduces to the particle number conservation equation. Two examples of
application are: i) a self-phase modulation of a BE condensate beam where we
show that part of the... | 0502059v1 |
2006-01-14 | Chaotic Vibration of a Quarter-Car Model Excited by the Road Surface Profile | The Melnikov criterion is used to examine a global homoclinic bifurcation and
transition to chaos in the case of a quarter car model excited kinematically by
the road surface profile. By analyzing the potential an analytic expression is
found for the homoclinic orbit. By introducing an harmonic excitation term and
damp... | 0601030v1 |
2006-01-14 | Transition to Chaos in the Self-Excited System with a Cubic Double Well Potential and Parametric Forcing | We examine the Melnikov criterion for a global homoclinic bifurcation and a
possible transition to chaos in case of a single degree of freedom nonlinear
oscillator with a symmetric double well nonlinear potential. The system was
subjected simultaneously to parametric periodic forcing and self excitation via
negative da... | 0601032v1 |
2006-07-19 | Energy flux fluctuations in a finite volume of turbulent flow | The flux of turbulent kinetic energy from large to small spatial scales is
measured in a small domain B of varying size R. The probability distribution
function of the flux is obtained using a time-local version of Kolmogorov's
four-fifths law. The measurements, made at a moderate Reynolds number, show
frequent events ... | 0607044v1 |
2006-08-09 | Statistical properties of the continuum Salerno model | The statistical properties of the Salerno model is investigated.
In particular, a comparison between the coherent and partially coherent wave
modes is made for the case of a random phased wave packet. It is found that the
random phased induced spectral broadening gives rise to damping of
instabilities, but also a bro... | 0608016v1 |
2006-10-18 | Whitham method for Benjamin-Ono-Burgers equation and dispersive shocks in internal waves in deep fluid | The Whitham modulation equations for the parameters of a periodic solution
are derived using the generalized Lagrangian approach for the case of damped
Benjamin-Ono equation. The structure of the dispersive shock in internal wave
in deep water is considered by this method. | 0610039v1 |
2007-03-28 | Quasi-Patterns in a Model of Multi-Resonantly Forced Chemical Oscillations | Multi-frequency forcing of systems undergoing a Hopf bifurcation to spatially
homogeneous oscillations is investigated using a complex Ginzburg-Landau
equation that systematically captures weak forcing functions that
simultaneously hit the 1:1-, the 1:2-, and the 1:3-resonance. Weakly nonlinear
analysis shows that gene... | 0703059v1 |
2001-06-09 | Conditions for Isoscaling in Nuclear Reactions | Isoscaling, where ratios of isotopes emitted from two reactions exhibit an
exponential dependence on the neutron and proton number of the isotope, has
been observed over a variety of reactions including evaporation, strongly
damped binary collision, and multifragmentation. The conditions for isoscaling
to occur as well... | 0106009v1 |
1992-12-25 | Chaotic Behavior in Warm Deformed Nuclei Induced by Residual Two-Body Interactions | Band mixing calculations in rapidly rotating well-deformed nuclei are
presented, investigating the properties of energy levels and rotational
transitions as a function of excitation energy. Substantial fragmentation of E2
transitions is found for $E_x \gsim$ 800 keV above yrast, which represents the
onset of rotational... | 9212015v1 |
1993-07-07 | Color Diffusion and Conductivity in a Quark-Gluon Plasma | Color diffusion is shown to be an important dissipative property of
quark-gluon plasmas that rapidly damps collective color modes. We derive the
characteristic color relaxation time scale, $t_c\approx (3\alpha_s T
\log(m_E/m_M ))^{-1}$, showing its sensitivity to the ratio of the static color
electric and magnetic scre... | 9307007v1 |
1994-04-18 | Vibrations versus collisions and the iterative structure of two-body dynamics | We adopt a truncated version of two-body dynamics by neglecting three-body
correlations, as is supported by microscopic numerical calculations.
Introducing orthogonal channel correlations for the pp- and the ph-channel and
integrating the latter in terms of vibrational RPA-states we derive a retarded
two-body equation.... | 9404020v1 |
1994-07-01 | Friedel Oscillations in Relativistic Nuclear Matter | We calculate the low-momentum N-N effective potential obtained in the OBE
approximation, inside a nuclear plasma at finite temperature, as described by
the relativistic $ \sigma $-$ \omega $ model. We analyze the screening effects
on the attractive part of the potential in the intermediate range as density or
temperatu... | 9407002v1 |
1995-12-19 | Macroscopic Features of Light Heavy-Ion Fission Reactions | Global macroscopic features observed in the fully-damped binary processes in
light di-nuclear systems, such as limiting angular momenta, mean total kinetic
energies and energy thresholds for fusion-fission processes (''fission
thresholds") are presented. Their deduced systematics are consistent with that
obtained for h... | 9512025v1 |
1995-12-28 | Classical and Quantal Irregular Scatterings with Complex Target | One-dimensional scattering by a target with two internal degrees of freedom
is investigated. The damping of resonance peaks and the associated appearance
of the fluctuating background in the quantum inelastic scattering amplitudes
are found. Examination of the analog classical system reveals a disorderly
reaction funct... | 9512038v1 |
1996-03-21 | Time development of a density perturbation in the unstable nuclear matter | We present the solution of the time development of an unstable initial
density perturbation in the linearized Vlasov equation, completing the previous
analysis in the literature. The additional contributions found are usually
damped and can be neglected at large times in the unstable region. The work
clarifies also the... | 9603029v2 |
1997-02-12 | A self-consistent treatment of the dynamics of 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... | 9702029v1 |
1998-07-27 | Isovector Vibrations in Nuclear Matter at Finite Temperature | We consider the propagation and damping of isovector excitations in heated
nuclear matter within the Landau Fermi-liquid theory. Results obtained for
nuclear matter are applied to calculate the Giant Dipole Resonance (GDR) at
finite temperature in heavy spherical nuclei within Steinwedel and Jensen
model.
The centroi... | 9807070v1 |
1998-09-03 | Relaxation of fast collective motion in heated nuclei | The damping of the collective vibrations in hot nuclei is studied within the
semiclassical Vlasov-Landau kinetic theory. The extention of the method of
independent sources of dissipation is used to allow for irreversible energy
transfer by chaos weighted wall formula. The expressions for the intrinsic
width of the gian... | 9809010v1 |
1998-09-04 | An investigation of interplay between dissipation mechanisms in heated Fermi systems by means of radiative strength functions | A simple analytical expression for the gamma-decay strength function is
derived with microcanonical ensemble for initial excited states. The approach
leads to both a non-zero limit of the strength function for vanishing gamma-ray
energy and a partial breakdown of Brink hypothesis. It is shown that the low
energy behavi... | 9809012v1 |
1998-09-11 | Damping of giant resonances in asymmetric nuclear matter | The giant collective modes in asymmetric nuclear matter are investigated
within a dynamic relaxation time approximation. We derive a coupled dispersion
relation and show that two sources of coupling appear: (i) a coupling of
isoscalar and isovector modes due to different mean-fields acting and (ii) an
explicit new coup... | 9809035v1 |
1998-10-01 | Giant Octupole Resonance Simulation | Using a pseudo-particle technique we simulate large-amplitude isoscalar giant
octupole excitations in a finite nuclear system. Dependent on the initial
conditions we observe either clear octupole modes or over-damped octupole modes
which decay immediately into quadrupole ones. This shows clearly a behavior
beyond linea... | 9810005v3 |
1998-10-14 | Finite Temperature Nuclear Response in Extended Random-Phase Approximation | The nuclear collective response at finite temperature is investigated for the
first time in the quantum framework of the small amplitude limit of the
extended TDHF approach, including a non-Markovian collision term. It is shown
that the collision width satisfies a secular equation. By employing a Skyrme
force, the isos... | 9810042v1 |
1999-05-07 | Influence of damping on the excitation of the double giant resonance | We study the effect of the spreading widths on the excitation probabilities
of the double giant dipole resonance. We solve the coupled-channels equations
for the excitation of the giant dipole resonance and the double giant dipole
resonance. Taking Pb+Pb collisions as example, we study the resulting effect on
the excit... | 9905018v2 |
2000-03-15 | Double giant dipole resonances in time-dependent density-matrix theory | The strength functions of the DGDRs in 16O and 40Ca are calculated using an
extended version of TDHF known as the time-dependent density-matrix theory
(TDDM). The calculations are done in a self-consistent manner, in which the
same Skyrme force as that used for the mean-field potential is used as the
residual interacti... | 0003034v2 |
2001-06-28 | Description of Double Giant Dipole Resonance within the Phonon Damping Model | In a recent Letter [1] an overall agreement with the experimental data for
the excitation of the single and double giant dipole resonances in relativistic
heavy ion collision in 136Xe and 208Pb nuclei has been reported. We point out
that this agreement is achieved by a wrong calculation of the DGDR excitation
mechanism... | 0106065v1 |
2001-11-08 | Note on the Deformed Boson Scheme in Time-Dependent Variational Method | The Holstein-Primakoff representation for the su(2)-algebra is derived in the
deformed boson scheme. The following two points are discussed : (i) connection
between a simple Hamiltonian and the Hamiltonian obeying the su(2)-algebra such
as Lipkin model and (ii) derivation of the Hamiltonian for describing the
damped an... | 0111029v1 |
2002-10-15 | Non-Markovian Collision Integral in Fermi-systems | The non-Markovian collision integral is obtained on the base of the
Kadanoff-Baym equations for Green functions in a form with allowance for small
retardation effects. The collisional relaxation times and damping width of the
giant isovector dipole resonances in nuclear matter are calculated. For an
infinite Fermi liqu... | 0210046v1 |
2003-04-07 | Mean first passage time for fission potentials having structure | A schematic model of over-damped motion is presented which permits one to
calculate the mean first passage time for nuclear fission. Its asymptotic value
may exceed considerably the lifetime suggested by Kramers rate formula, which
applies only to very special, favorable potentials and temperatures. The
additional time... | 0304022v1 |
2003-09-05 | Pairing effect on the giant dipole resonance width at low temperature | The width of the giant dipole resonance (GDR) at finite temperature T in
Sn-120 is calculated within the Phonon Damping Model including the neutron
thermal pairing gap determined from the modified BCS theory. It is shown that
the effect of thermal pairing causes a smaller GDR width at T below 2 MeV as
compared to the o... | 0309010v1 |
2003-12-19 | Response in the continuum for light deformed neutron-rich nuclei | The time-dependent Hartree-Fock calculation with a full Skyrme energy
functional has been carried out on the three-dimensional Cartesian lattice
space to study E1 giant dipole resonances (GDR) in light nuclei. The outgoing
boundary condition for the continuum states is treated by the absorbing complex
potential. The ca... | 0312089v1 |
2004-11-18 | Nuclear giant resonances | This talk presents the recent status of theoretical and experimental studies
of giant resonances in nuclei with the emphasis on: (1) charge-exchange
Gamow-Teller resonance, (2) multiple-phonon resoanances, (3) giant dipole
resonances in highly excited nuclei, and (4) pygmy dipole resonances in neutron
rich nuclei. In p... | 0411073v1 |
1996-06-04 | Direct Hopf Bifurcation in Parametric Resonance of Hybridized Waves | We study parametric resonance of interacting waves having the same wave
vector and frequency. In addition to the well-known period-doubling instability
we show that under certain conditions the instability is caused by a Hopf
bifurcation leading to quasiperiodic traveling waves. It occurs, for example,
if the group vel... | 9605006v1 |
1999-05-27 | Impurity-induced stabilization of solitons in arrays of parametrically driven nonlinear oscillators | Chains of parametrically driven, damped pendula are known to support
soliton-like clusters of in-phase motion which become unstable and seed
spatiotemporal chaos for sufficiently large driving amplitudes. We show that
the pinning of the soliton on a "long" impurity (a longer pendulum) expands
dramatically its stability... | 9905009v1 |
1999-11-19 | Origin of Multikinks in Dispersive Nonlinear Systems | We develop {\em the first analytical theory of multikinks} for strongly {\em
dispersive nonlinear systems}, considering the examples of the weakly discrete
sine-Gordon model and the generalized Frenkel-Kontorova model with a piecewise
parabolic potential. We reveal that there are no $2\pi$-kinks for this model,
but the... | 9911006v1 |
1998-02-04 | The steady state of a pumped and damped atom laser | This paper has been withdrawn, as further work has shown that an atom laser
as described by the model herein does not have a steady state, so it doesn't
matter much what it would look like. | 9802008v2 |
1998-02-20 | Phase Dynamics of Bose-Einstein Condensates: Losses versus Revivals | In the absence of losses the phase of a Bose-Einstein condensate undergoes
collapses and revivals in time due to elastic atomic interactions. As
experiments necessarily involve inelastic collisions, we develop a model to
describe the phase dynamics of the condensates in presence of collisional
losses. We find that a fe... | 9802040v1 |
1998-02-25 | Radiation Reaction fields for an accelerated dipole for scalar and electromagnetic radiation | The radiation reaction fields are calculated for an accelerated changing
dipole in scalar and electromagnetic radiation fields. The acceleration
reaction is shown to alter the damping of a time varying dipole in the EM case,
but not the scalar case. In the EM case, the dipole radiation reaction field
can exert a force ... | 9802047v1 |
1998-03-27 | Semiclassical spin damping: Superradiance revisited | A well known description of superradiance from pointlike collections of many
atoms involves the dissipative motion of a large spin. The pertinent
``superradiance master equation'' allows for a formally exact solution which we
subject to a semiclassical evaluation. The clue is a saddle-point approximation
for an inverse... | 9803041v1 |
1999-12-24 | Differential criterion of a bubble collapse in viscous liquids | The present work is devoted to a model of bubble collapse in a Newtonian
viscous liquid caused by an initial bubble wall motion. The obtained bubble
dynamics described by an analytic solution significantly depends on the liquid
and bubble parameters. The theory gives two types of bubble behavior: collapse
and viscous d... | 9912050v1 |
1999-12-27 | Rutherford Scattering with Retardation | Numerical solutions for Sommerfeld model in nonrelativistic case are
presented for the scattering of a spinless extended charged body in a static
Coulomb field of a fixed point charge. It is shown that differential cross
section for extended body preserves the form of the Rutherford result with
multiplier, not equal to... | 9912051v2 |
2000-08-04 | A Variational Approach in the Dissipative Nonlinear Schrödinger Equation | The properties of pulse propagation in a nonlinear fiber including linear
damped term added in the usual nonlinear Schr\"odinger equation is analyzed
analytically. We apply variational modified approach based on the lagrangian
that describe the dynamic of system and with a trial function we obtain a
solution which is m... | 0008011v1 |
2000-12-21 | Intrabeam Scattering Analysis of ATF Beam Data Taken in April 2000 | In April 2000 the single bunch energy spread, bunch length, horizontal
emittance, and vertical emittance were measured as functions of current in
KEK's ATF damping ring. In this report the measurement results are analyzed in
light of intrabeam scattering theory. The measurements are found to be
relatively consistent wi... | 0012055v1 |
2001-03-09 | Trapping oscillations, discrete particle effects and kinetic theory of collisionless plasma | Effects induced by the finite number $N$ of particles on the evolution of a
monochromatic electrostatic perturbation in a collisionless plasma are
investigated. For growth as well as damping of a single wave, discrete particle
numerical simulations show a $N$-dependent long time behavior which differs
from the numerica... | 0103025v1 |
2001-05-30 | Impedance Analysis of Bunch Length Measurements at the ATF Damping Ring | We present energy spread and bunch length measurements at the Accelerator
Test Facility (ATF) at KEK, as functions of current, for different ring rf
voltages, and with the beam both on and off the coupling resonance. We fit the
on-coupling bunch shapes to those of an impedance model consisting of a
resistor and an indu... | 0105102v1 |
2001-12-14 | Active Vibration Suppression R&D for the NLC | The nanometer scale beam sizes at the interaction point in linear colliders
limit the allowable motion of the final focus magnets. We have constructed a
prototype system to investigate the use of active vibration damping to control
magnet motion. Inertial sensors are used to measure the position of a test
mass, and a D... | 0112042v1 |
2002-04-15 | Laser-Generated Ultrashort Multi-Megagauss Magnetic Pulses in Plasmas | We demonstrate ultrashort (6 ps), multi-Megagauss (27 MG) magnetic pulses
generated upon interaction of an intense laser pulse (10^{16} Wcm^-2, 100 fs)
with a solid target. The temporal evolution of these giant fields generated
near the high density critical layer is obtained with the highest resolution
reported so far... | 0204039v1 |
2002-04-29 | Neutral Plasma Oscillations at Zero Temperature | We use cold plasma theory to calculate the response of an ultracold neutral
plasma to an applied rf field. The free oscillation of the system has a
continuous spectrum and an associated damped quasimode. We show that this
quasimode dominates the driven response. We use this model to simulate plasma
oscillations in an e... | 0204084v1 |
2002-09-04 | Vortex Ring Reconnections | We investigate numerically the Navier-Stokes dynamics of reconnecting vortex
rings at small $Re$ number. We find that reconnections are dissipative due to
the smoothing of vorticity gradients at reconnection kinks and to the formation
of secondary structures of stretched anti-parallel vorticity which transfer
kinetic e... | 0209014v1 |
2002-11-05 | Analise Termodinamica da aceleracao de uma massa | We analyse the acceleration of a mass with a simple structure taking into
account Thermodynamics. Two situations are analysed. The first one for the
application of a localized force to a point of the mass. The second one for the
application of a force to the entire mass. The two situations are not
equivalent. For the f... | 0211021v1 |
2003-05-30 | A Sum Rule for Nonlinear Optical Susceptibilities | It is explicitly shown, for optical processes arbitrarily comprising two-,
three- or four-photon interactions, that the sum over all matter states of any
optical susceptibility is exactly zero. The result remains true even in
frequency regions where damping is prominent. Using a quantum electrodynamical
framework to re... | 0305131v1 |
2003-10-16 | Ionization of clusters in intense laser pulses through collective electron dynamics | The motion of electrons and ions in medium-sized rare gas clusters (1000
atoms) exposed to intense laser pulses is studied microscopically by means of
classical molecular dynamics using a hierarchical tree code. Pulse parameters
for optimum ionization are found to be wavelength dependent. This resonant
behavior is trac... | 0310073v1 |
2003-11-14 | Transverse modulational instability of partially incoherent soliton stripes | Based on the Wigner distribution approach, an analysis of the effect of
partial incoherence on the transverse instability of soliton structures in
nonlinear Kerr media is presented. It is explicitly shown, that for a
Lorentzian incoherence spectrum the partial incoherence gives rise to a damping
which counteracts, and ... | 0311068v1 |
2004-02-13 | Ion energy balance during fast wave heating in TORE SUPRA | Direct coupling of the fast magnetosonic wave to the electrons has been
studied on the tokamak TORE SUPRA. Preliminary experiments were dedicated to
optimise the scenario for Fast Wave Electron Heating (FWEH) and Current Drive
(FWCD). In a first part, thermal kinetic and diamagnetic energy are compared
when fast wave i... | 0402067v1 |
2004-04-14 | Earthquakes temporal occurrence: a statistical study | The distribution of inter-occurrence time between seismic events is a
quantity of great interest in seismic risk assessment. We evaluate this
distribution for different models of earthquakes occurrence and follow two
distinct approaches: The non homogeneous Poissonian and the non Poissonian one.
In all cases we obtain ... | 0404068v1 |
2004-07-14 | Exponential versus linear amplitude decay in damped oscillators | We comment of the widespread belief among some undergraduate students that
the amplitude of any harmonic oscillator in the presence of any type of
friction, decays exponentially in time. To dispel that notion, we compare the
amplitude decay for a harmonic oscillator in the presence of (i) viscous
friction and (ii) dry ... | 0407080v1 |
2004-10-21 | Kinetic effects in strong Langmuir turbulence | Kinetic effects with regard to a one dimensional Langmuir soliton-like pulse
are investigated. Though thus far mainly transit-time accelerations have been
investigated regarding strong Langmuir turbulence, it is found that
ponderomotive reflections (generalized nonlinear Landau damping) may play
important roles also. T... | 0410179v2 |
2005-01-07 | Velocity-Space Diffusion in a Perpendicularly Propagating Electrostatic Wave | The motion of ions in the fields B = B_0 zhat and E = E_0 yhat cos(k_perp y -
omega t) is considered. When omega >> Omega_i and v_perp > omega/k_perp, the
equations of motion may be reduced to a set of difference equations. These
equations exhibit stochastic behavior when E_0 exceeds a threshold. The
diffusion coeffici... | 0501035v1 |
2005-02-02 | Swinging of two-dimensional solitons in harmonic and Bessel optical lattices | We consider parametric amplification of two-dimensional spatial soliton
swinging in longitudinally modulated harmonic and Bessel lattices in Kerr-type
saturable medium. We show that soliton center oscillations along different axes
in two-dimensional lattices are coupled, which give rise to a number of
interesting propa... | 0502009v1 |
2005-09-13 | A Landau fluid model for warm collisionless plasmas | A Landau fluid model for a collisionless electron-proton magnetized plasma,
that accurately reproduces the dispersion relation and the Landau damping rate
of all the magnetohydrodynamic waves, is presented. It is obtained by an
accurate closure of the hydrodynamic hierarchy at the level of the fourth order
moments, bas... | 0509091v1 |
2005-10-13 | An illustrative experiment on electromagnetic oscillations | It is the purpose of this manuscript to place an illustrative demonstration
on the measurement of damped electromagnetic oscillations for a RLC circuit
that it is easy to set in any physics laboratory equipped with PASCO
technologies and USB Electrical PASPort sensors together with standard
electrical components. The r... | 0510122v1 |
2005-12-20 | Coupled atomic-molecular condensates in a double-well potential: decaying molecular oscillations | We present a four-mode model that describes coherent photo-association (PA)
in a double-well Bose-Einstein condensate, focusing on the $average$ molecular
populations in certain parameters. Our numerical results predict an interesting
strong-damping effect of molecular oscillations by controlling the particle
tunnellin... | 0512184v2 |
2007-02-21 | Liquid-infiltrated photonic crystals: Ohmic dissipation and broadening of modes | The pronounced light-matter interactions in photonic crystals make them
interesting as opto-fludic "building blocks" for lab-on-a-chip applications. We
show how conducting electrolytes cause dissipation and smearing of the
density-of-states, thus altering decay dynamics of excited bio-molecules
dissolved in the electro... | 0702176v1 |
2004-04-08 | Mathematical Analysis and Simulations of the Neural Circuit for Locomotion in Lamprey | We analyze the dynamics of the neural circuit of the lamprey central pattern
generator (CPG). This analysis provides insights into how neural interactions
form oscillators and enable spontaneous oscillations in a network of damped
oscillators, which were not apparent in previous simulations or abstract phase
oscillator... | 0404012v1 |
2005-08-11 | Time Reversal of the Increasing Geometrical Progression of the Population of a Simple Biological Specie | In this work we consider time reversal of the increasing geometrical
progression of the population of a simple biological species without any
enemies (predators) in the appropriate environment with unlimited resources
(food, territory, etc.). It is shown that such time reversal corresponds to
appearance of the cannibal... | 0508011v1 |
1996-06-11 | Condensate fluctuations of a trapped, ideal Bose gas | For a non-self-interacting Bose gas with a fixed, large number of particles
confined to a trap, as the ground state occupation becomes macroscopic, the
condensate number fluctuations remain micrscopic. However, this is the only
significant aspect in which the grand canonical description differs from
canonical or microc... | 9606009v2 |
1996-11-27 | A precision test of decoherence | The motion of a charged particle over a conducting plate is damped by Ohmic
resistance to image currents. This interaction between the particle and the
plate must also produce decoherence, which can be detected by examining
interference patterns made by diffracted particle beams which have passed over
the plate. Becaus... | 9611049v2 |
1997-03-16 | Least-squares inversion for density-matrix reconstruction | We propose a method for reconstruction of the density matrix from measurable
time-dependent (probability) distributions of physical quantities. The
applicability of the method based on least-squares inversion is - compared with
other methods - very universal. It can be used to reconstruct quantum states of
various syst... | 9703026v1 |
1997-04-02 | Approximate quantum error correction can lead to better codes | We present relaxed criteria for quantum error correction which are useful
when the specific dominant noise process is known. These criteria have no
classical analogue. As an example, we provide a four-bit code which corrects
for a single amplitude damping error. This code violates the usual Hamming
bound calculated for... | 9704002v1 |
1997-04-08 | Measured Quantum Dynamics of a Trapped Ion | The measurement process is taken into account in the dynamics of trapped ions
prepared in nonclassical motional states. The induced decoherence is shown to
manifest itself both in the inhibition of the internal population dynamics and
in a damping of the vibrational motion without classical counterpart.
Quantitative co... | 9704016v1 |
1997-09-09 | Quantum gravity and the problem of measurement | We discuss some arguments in favour of the proposal that the quantum
correlations contained in the pure state-vector evolving according to
Schoedinger equation can be eliminated by the action of multiply connected
wormholes during measurement. We devise a procedure to obtain a proper master
equation which governes the ... | 9709018v1 |
1998-04-06 | Field Oscillations in a Micromaser with Injected Atomic Coherence | The electric field in a lossless, regularly-pumped micromaser with injected
atomic coherence can undergo a period 2 oscillations in the steady state. The
field changes its value after a single atom passes through the micromaser
cavity, but returns to its original value after a second atom travels through.
We give a sim... | 9804017v1 |
1998-09-14 | Macroscopically distinct quantum superposition states as a bosonic code for amplitude damping | We show how macroscopically distinct quantum superposition states
(Schroedinger cat states) may be used as logical qubit encodings for the
correction of spontaneous emission errors. Spontaneous emission causes a bit
flip error which is easily corrected by a standard error correction circuit.
The method works arbitraril... | 9809037v2 |
1998-09-27 | Quantum Dynamics of Topological Singularities: Feynman's Influence Functional Approach | Starting from the microscopic theory of Bardeen-Cooper-Schrieffer (BCS) for
the fermionic superfluids, we show that the vortex dynamics can be followed
naturally by extending Feynman's influence functional approach to incorporate
the transverse force.
There is a striking mutual independence of the transverse and long... | 9809080v1 |
1998-11-14 | Two-atom dark states in electromagnetic cavities | The center-of-mass motion of two two-level atoms coupled to a single damped
mode of an electromagnetic resonator is investigated. For the case of one atom
being initially excited and the cavity mode in the vacuum state it is shown
that the atomic time evolution is dominated by the appearance of dark states.
These state... | 9811035v1 |
1998-12-17 | Coherence properties of the stochastic oscillator | An oscillator with stochastic frequency is discussed as a model for
evaluating the quantum coherence properties of a physical system. It is found
that the choice of jump statistics has to be considered with care if unphysical
consequences are to be avoided. We investigate one such model, evaluate the
damping it causes,... | 9812045v1 |
1999-04-14 | Quantum Langevin theory of excess noise | In an earlier work [P. J. Bardroff and S. Stenholm], we have derived a fully
quantum mechanical description of excess noise in strongly damped lasers. This
theory is used here to derive the corresponding quantum Langevin equations.
Taking the semi-classical limit of these we are able to regain the starting
point of Sie... | 9904060v1 |
1999-05-04 | Post-Markov master equation for the dynamics of open quantum systems | A systematic first-order correction to the standard Markov master equation
for open quantum systems interacting with a bosonic bath is presented. It
extends the Markov Lindblad master equation to the more general case of
non-Markovian evolution. The meaning and applications of our `post'-Markov
master equation are illu... | 9905006v1 |
1999-06-18 | Zeno effect preventing Rabi transitions onto an unstable energy level | We consider a driven 2-level system with one level showing spontaneous decay
to an otherwise uncoupled third level. Rabi transitions to the unstable level
are strongly damped. This simple configuration can be used to demonstrate and
to explore the quantum Zeno effect leading to a freezing of the system to the
initial l... | 9906068v1 |
1999-06-29 | Non dissipative decoherence of Rabi oscillations | We present a simple theoretical description of two recent experiments where
damping of Rabi oscillations, which cannot be attributed to dissipative
decoherence, has been observed. This is obtained considering the evolution time
or the Hamiltonian as random variables and then averaging the usual unitary
evolution on a p... | 9906115v3 |
1999-07-30 | Quantum trajectories for Brownian motion | We present the stochastic Schroedinger equation for the dynamics of a quantum
particle coupled to a high temperature environment and apply it the dynamics of
a driven, damped, nonlinear quantum oscillator. Apart from an initial slip on
the environmental memory time scale, in the mean, our result recovers the
solution o... | 9907100v1 |
2000-03-30 | Stochastic dynamics of electronic wave packets in fluctuating laser fields | The dynamics of a laser-excited Rydberg electron under the influence of a
fluctuating laser field are investigated. Rate equations are developed which
describe these dynamics in the limit of large laser bandwidths for arbitrary
types of laser fluctuations. These equations apply whenever all coherent
effects have alread... | 0003139v1 |
2000-07-12 | Single photon generation by pulsed excitation of a single dipole | The fluorescence of a single dipole excited by an intense light pulse can
lead to the generation of another light pulse containing a single photon. The
influence of the duration and energy of the excitation pulse on the number of
photons in the fluorescence pulse is studied. The case of a two-level dipole
with strongly... | 0007037v1 |
2000-08-22 | Effective Hamiltonian Approach to the Master Equation | A method of exactly solving the master equation is presented in this letter.
The explicit form of the solution is determined by the time evolution of a
composite system including an auxiliary system and the open system in question.
The effective Hamiltonian governing the time evolution of the composed system
are derive... | 0008090v1 |
2001-01-01 | Quantum-Liouville and Langevin Equations for Gravitational Radiation Damping | From a forward--backward path integral, we derive a master equation for the
emission and absorption of gravitons by a massive quantum object in a heat bath
of gravitons. Such an equation could describe collapse phenomena of dense
stars. We also present a useful approximate Langevin equation for such a
system. | 0101006v1 |
2001-02-26 | Bateman's dual system revisited: I. Quantization, geometric phase and relation with the ground-state energy of the linear harmonic oscillator | By using the Feynman-Hibbs prescription for the evolution amplitude, we
quantize the system of a damped harmonic oscillator coupled to its
time-reversed image, known as Bateman's dual system.
The time-dependent quantum states of such a system are constructed and
discussed entirely in the framework of the classical th... | 0102128v2 |
2001-03-14 | Decoherence effects of motion-induced radiation | The radiation pressure coupling with vacuum fluctuations gives rise to energy
damping and decoherence of an oscillating particle. Both effects result from
the emission of pairs of photons, a quantum effect related to the fluctuations
of the Casimir force. We discuss different alternative methods for the
computation of ... | 0103083v1 |
2001-04-27 | Time Evolution of tunneling and decoherence: soluble model | Decoherence effects associated to the damping of a tunneling two-level system
are shown to dominate the tunneling probability at short times in strong
coupling regimes in the context of a soluble model. A general decomposition of
tunneling rates in dissipative and unitary parts is implemented. Master
equation treatment... | 0104132v1 |
2001-08-01 | Heating and decoherence suppression using decoupling techniques | We study the application of decoupling techniques to the case of a damped
vibrational mode of a chain of trapped ions, which can be used as a quantum bus
in linear ion trap quantum computers. We show that vibrational heating could be
efficiently suppressed using appropriate ``parity kicks''. We also show that
vibration... | 0108007v3 |
2001-11-29 | Field quantization for chaotic resonators with overlapping modes | Feshbach's projector technique is employed to quantize the electromagnetic
field in optical resonators with an arbitray number of escape channels. We find
spectrally overlapping resonator modes coupled due to the damping and noise
inflicted by the external radiation field. For wave chaotic resonators the mode
dynamics ... | 0111156v2 |
2001-12-08 | Quantum oscillations without quantum coherence | We study numerically the damping of quantum oscillations and the increase of
entropy with time in model spin systems decohered by a spin bath. In some
experimentally relevant cases, the oscillations of considerable amplitude can
persist long after the entropy has saturated near its maximum, i.e. when the
system has bee... | 0112053v1 |
2001-12-10 | Temporal Oscillations of Nonlinear Faraday Rotation in Coherently Driven Media | New phenomenon of temporal oscillations of nonlinear Faraday rotation in a
driven four-level system is predicted. We show that in this system with one
upper level, under the conditions of electromagnetically induced transparency
created by a strong coupling field, the polarization rotation of weak probe
light exhibits ... | 0112058v1 |
2001-12-31 | Resonances and spectral properties of detuned OPO pumped by fluctuating sources | Twin beam fluctuations are analyzed for detuned and mismatched OPO
configurations. Resonances and frequency responses to the quantum noise sources
(quantum and pump amplitude/phase fluctuations) are examined as functions of
cavity decay rates, excitation parameter and detuning. The dependence of self-
and mutual correl... | 0112180v2 |
2002-03-04 | Stationary cantilever vibrations in the oscillating cantilever-driven adiabatic reversals -- magnetic resonance force microscopy technique | We consider theoretically the novel technique in magnetic resonance force
microscopy which is called ``oscillating cantilever-driven adiabatic
reversals''. We present analytical and numerical analysis for the stationary
cantilever vibrations in this technique. For reasonable values of parameters we
estimate the resonan... | 0203013v1 |
2002-05-17 | Embedding dissipation and decoherence in unitary evolution schemes | Dissipation and decoherence, and the evolution from pure to mixed states in
quantum physics are handled through master equations for the density matrix. By
embedding elements of this matrix in a higher-dimensional Liouville-Bloch
equation, the methods of unitary integration are adapted to solve for the
density matrix a... | 0205113v3 |
2002-05-31 | Invitation to quantum dynamical semigroups | The theory of quantum dynamical semigroups within the mathematically rigorous
framework of completely positive dynamical maps is reviewed. First, the
axiomatic approach which deals with phenomenological constructions and general
mathematical structures is discussed. Then basic derivation schemes of the
constructive app... | 0205188v1 |
2002-06-14 | An Inverse-Problem Approach to Designing Photonic Crystals for Cavity QED Experiments | Photonic band gap (PBG) materials are attractive for cavity QED experiments
because they provide extremely small mode volumes and are monolithic,
integratable structures. As such, PBG cavities are a promising alternative to
Fabry-Perot resonators. However, the cavity requirements imposed by QED
experiments, such as the... | 0206094v1 |
2002-06-17 | Damped Bloch oscillations of cold atoms in optical lattices | The paper studies Bloch oscillations of cold neutral atoms in the optical
lattice. The effect of spontaneous emission on the dynamics of the system is
analyzed both analytically and numerically. The spontaneous emission is shown
to cause (i) the decay of Bloch oscillations with the decrement given by the
rate of sponta... | 0206108v1 |
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