We show that for an open quantum system which is classically chaotic (a quartic double well with harmonic driving coupled to a sea of harmonic oscillators) the rate of entropy production has, as a function of time, two relevant regimes: For short times it is proportional to the diffusion coefficient (fixed by the system-environment coupling strength). For longer times (but before equilibration) there is a regime where the entropy production rate is fixed by the Lyapunov exponent. The nature of the transition time between both regimes is investigated.
We analyze the quantum to classical transition of the order parameter in
second order phase transitions. We consider several toy models in non
relativistic quantum mechanics. We study the dynamical evolution of a wave
packet initially peaked around a local maximum of the potential using
variational approximations and also exact numerical results. The influence of
the environment on the evolution of the density matrix and the Wigner function
is analyzed in great detail. We also discuss the relevance of our results to
the analysis of phase transitions in field theory. In particular, we argue that
previous results about classicality of the order parameter in O(N) models may
be consequences of the large $N$ approximation.Comment: RevTex file, 15 pages, 19 ps figures. Minor changes, to appear in
Physical Review
Abstran A formalism is developed for calculahg Beny phases for non-adiabatic timeperiodic quantum systems when a dynamical invariant is known. It is found that, when the invariant is periodic and has a non-degenerate spectrum, this method allows a convenient way to obtain generalired Beny phases and the pmper cyclic initial states. The method is applied to Lhe generalized harmonic oscillator and the two-level system, where the invariant operaton are explicilly constructed. Formulae for the mnventional Beny's phases are readily obtained by taking the adiabatic limit of the exact results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.