Dynamics of quantum and classical correlations of a two-atom system in thermal reservoirs

The dynamical behavior of quantum and classical correlations between two atoms coupled with thermal reservoirs is investigated. Intuitively, one believes that measures of quantum discord can never be less than those of entanglement. However, our results show that quantum discord and classical correlation may be smaller or larger than entanglement as measure with concurrence, and classical correlation is always less than quantum discord in thermal environments. In addition, we find that the quantifier of the correlations, quantum discord and geometric quantum discord, generally exhibits a dynamical behavior to be different from each other, but it tends to be consistent as mean photon number increases.