The moving preferred basis in open systems

SEBASTIAN FORTIN; MARIO CASTAGNINO

Dresden

Workshop; International Workshop: Quantum Physics with Non-Hermitian Operators; 2011

Max Planck Institute of Physics

There are many formalisms to describe quantum decoherence. However, many of them give non general and ad hoc definition of "pointer basis" or "moving preferred basis", and this fact is a problem for the decoherence program. In our contribution, using the well known Environment Induced Decoherence formalism, we will consider quantum systems under a general theoretical framework for decoherence and present a tentative very general definition of the moving preferred basis and the relaxation and decoherence times. The formalism is based on finding the poles of the Hamiltonian and from them all the possible decaying modes of the non-unitary evolution of the open quantum system. Then, with all the possible decaying modes, we can construct a Non-Hermitian Hamiltonian describing the behavior of the open system unit. Since the catalogue of the poles contains the whole information about the decoherence process, one should be able to define the decoherence time and the preferred basis from this catalogue. This preferred basis is implemented, and the characteristic times are computed, in a well known open system model with a Hamiltonian of an oscillator in a bath of oscillators and a rotating wave interaction. The obtained decoherence and the relaxation times coincide with those of a similar model of Omnès.