217 research outputs found
Energy diffusion in strongly driven quantum chaotic systems
The energy evolution of a quantum chaotic system under the perturbation that
harmonically depends on time is studied for the case of large perturbation, in
which the rate of transition calculated from the Fermi golden rule exceeds the
frequency of perturbation. It is shown that the energy evolution retains its
diffusive character, with the diffusion coefficient that is asymptotically
proportional to the magnitude of perturbation and to the square root of the
density of states. The results are supported by numerical calculation. They
imply the absence of the quantum-classical correspondence for the energy
diffusion and the energy absorption in the classical limit .Comment: 12 pages, 3 figures, RevTe
Gibbs attractor: a chaotic nearly Hamiltonian system, driven by external harmonic force
A chaotic autonomous Hamiltonian systems, perturbed by small damping and
small external force, harmonically dependent on time, can acquire a strange
attractor with properties similar to that of the canonical distribution - the
Gibbs attractor. The evolution of the energy in such systems can be described
as the energy diffusion. For the nonlinear Pullen - Edmonds oscillator with two
degrees of freedom the properties of the Gibbs attractor and their dependence
on parameters of the perturbation are studied both analytically and
numerically.Comment: 8 pages RevTeX, 3 figure
Polarized solitons in a cubic-quintic medium
The interaction of both scalar and counter-rotating polarized steady state
pulses (SSP) is studied numerically for a medium characterized by nonlinear
susceptibilities of the third and the fifth order (a cubic-quintic medium
with,). The collision of two plateau-shaped solitons
proved to be essentially inelastic, as a number of secondary elliptically
polarized solitary waves arise as a result of interaction of steady-state
pulses.Comment: 11 pages, 9 figures, PDF onl
On the influence of noise on chaos in nearly Hamiltonian systems
The simultaneous influence of small damping and white noise on Hamiltonian
systems with chaotic motion is studied on the model of periodically kicked
rotor. In the region of parameters where damping alone turns the motion into
regular, the level of noise that can restore the chaos is studied. This
restoration is created by two mechanisms: by fluctuation induced transfer of
the phase trajectory to domains of local instability, that can be described by
the averaging of the local instability index, and by destabilization of motion
within the islands of stability by fluctuation induced parametric modulation of
the stability matrix, that can be described by the methods developed in the
theory of Anderson localization in one-dimensional systems.Comment: 10 pages REVTEX, 9 figures EP
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