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Average quantum dynamics of closed systems over stochastic Hamiltonians
Li Yu1,2, Daniel F V James3
1Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON, M5S 1A7, Canada. li.yu.phys@hotmail.com.
Abstract:
We develop a formally exact master equation to describe the evolution of the average density matrix of a closed quantum system driven by a stochastic Hamiltonian. The average over stochastic processes generally results in decoherence effects in closed system dynamics, in addition to the unitary evolution. We then show that, for an important class of problems in which the Hamiltonian is proportional to a Gaussian random process, the 2nd-order master equation yields exact dynamics. The general formalism is applied to study the examples of a two-level system, two atoms in a stochastic magnetic field and the heating of a trapped ion, where we find phenomena such as decoherence-induced disentanglement.
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