Decoherence for classically chaotic quantum maps

We study the behavior of an open quantum system, with an N-dimensional space of states, whose density matrix evolves according to a nonunitary map defined in two steps: A unitary step, where the system evolves with an evolution operator obtained by quantizing a classically chaotic map (baker’s map a...

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Autores principales: Bianucci, P., Paz, J.P., Saraceno, M.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_1063651X_v65_n4_p12_Bianucci
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Sumario:We study the behavior of an open quantum system, with an N-dimensional space of states, whose density matrix evolves according to a nonunitary map defined in two steps: A unitary step, where the system evolves with an evolution operator obtained by quantizing a classically chaotic map (baker’s map and Harper’s map are the two examples we consider). A nonunitary step where the evolution operator for the density matrix mimics the effect of diffusion in the semiclassical (large [formula presented] limit. The process of decoherence and the transition from quantum to classical behavior are analyzed in detail by means of numerical and analytic tools. The existence of a regime where the entropy grows with a rate that is independent of the strength of the diffusion coefficient is demonstrated. The nature of the processes that determine the production of entropy is analyzed. © 2002 The American Physical Society.