Dissipação, termalização e descoerencia via acoplamento caotico / Dissipation, thermalization and decoherence through chaotic coupling

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

We study here how and under which conditions a chaotic system with only two degrees of freedom can produce irreversible phenomena such as dissipation, thermalization and, from the quantum point of view, decoherence in a simple system coupled to it. In the classical formulation of the problem, we describe analytically the behavior of the energy ux in Linear Response regime and we point the main ingredient for a chaotic system to produce irreversible effects: correlations with exponential decay. We show that it is possible to describe the asymptotic equilibrium even with a temperature, which seems to be a counter intuitive result for systems with few degrees of freedom. We formulate the problem from the quantum point of view using In uence Functionals approach. We show the formalism is very adequate since the chaotic system in uence is described by quantum analogues of the same functions we obtain in the Linear Response approach to the classical problem. We calculate those functions semiclassically and we show the lowest order terms of the semiclassical approximation evolve as given by classical chaotic dynamics. The time scales of the classical analysis are shown to be very important for the resolution of the quantum problem as well as the semiclassical analysis of the correlation functions. We show that dissipative and decoherence effects, in the quantum regime, are possible due to the chaotic dynamics of the system

ASSUNTO(S)

irreversibility irreversibilidade descoerencia semiclassical methods movimentos brownianos mecanica estatistica de não-equilibrio chaotic systems non-equilibrium statistical mechanics thermalization sistemas caoticos termalização brownian movements metodos semiclassicos decoherence

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