QUANTUM DISCORD AND CLASSICAL CORRELATIONS OF TWO BOSONIC MODES IN THE TWO-RESERVOIR MODEL

Within the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous variable quantum discord for a system consisting of two bosonic modes embedded in two independent thermal environments. We describe the evolution of discord in terms of the covariance matrix for Gaussian input states. In the case of an entangled initial squeezed thermal state, we analyze the evolution of the Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and show that quantum discord decays asymptotically in time under the effect of the thermal reservoirs. We describe also the evolution of classical correlations and show that they also decay asymptotically in time.