Emaranhamento e caos em um sistema de dois spins

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

In this project we have studied a two spin system under an anisotropic Heisenberg interaction and external magnetic fields acting on each spin separately. We have been able to relate fast decoherence of a quantum subsystem with the presence of chaos in the corresponding classical system. Such an association has been done making use of the coherent state representation of the Hamiltonian operator in the semiclassical regime. Each point in the phase space can be connected to a coherent wave packet centered there. In order to observe the decoherence process, we have followed the temporal evolution of the idempotency defect. With this procedure, we have noted that the entanglement time for those packets centered at a point with chaotic vicinities is less than those with regular vicinities. Another aspect observed is that the idempotency defect reaches a plateau (at long times) that is higher in the chaotic cases as compared to the regular ones. Also, the time evolution of the reduced density matrix showed that the population of those packets located at the chaotic regions tends to become equally distributed, whereas those packets located at regular regions remains unequally distributed (the packets try to mantain the populations inside the region defined by the tori)

ASSUNTO(S)

caos quantico comportamento caotico nos sistemas

ACESSO AO ARTIGO

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