Dynamics of decoherence without dissipation in a squeezed thermal bath
Abstract
We study a generic open quantum system where the coupling between the system and its environment is of an energypreserving quantum nondemolition (QND) type. We obtain the general master equation for the evolution of such a system under the influence of a squeezed thermal bath of harmonic oscillators. From the master equation it can be seen explicitly that the process involves decoherence or dephasing without any dissipation of energy. We work out the decoherencecausing term in the high and zerotemperature limits and check that they match with known results for the case of a thermal bath. The decay of the coherence is quantified as well by the dynamics of the linear entropy of the system under various environmental conditions. We make a comparison of the quantum statistical properties between QND and dissipative types of evolution using a twolevel atomic system and a harmonic oscillator.
 Publication:

Journal of Physics A Mathematical General
 Pub Date:
 November 2007
 DOI:
 10.1088/17518113/40/45/014
 Bibcode:
 2007JPhA...4013735B