Dynamics of entangled states in a correlated reservoir

Abstract

Dynamics of entangled states of two independent single-mode cavities in a correlated (squeezed) reservoir are investigated in the context of matching the correlations contained in the entangled states to those contained in the reservoir. We illustrate our considerations by examining the time evolution of entanglement of initial single and double excitation NOON and EPR states, and a comparison is made of when each cavity is coupled to its own reservoir or both cavities are coupled to a common reservoir. It is shown that the evolution of the initial entanglement and transfer of entanglement from the squeezed reservoir to the cavity modes depend crucially on the matching of the initial correlations to those contained in the squeezed reservoir. In particular, it is found that initially entangled modes with correlations different from the reservoir correlations prevent the transfer of the correlations from the squeezed field to the modes. In addition, we find that the transient entanglement exhibits several features unique to the quantum nature of squeezing. In particular, we show that in the case of separate squeezed reservoirs the initial entanglement disappears at a finite time, which for the so-called classically squeezed field remains almost the same as in the case of a thermal field. In the case of a common reservoir a recurrence of entanglement occurs and we find that this feature also results from the reservoir correlations unique to quantum correlations. There is no revival of the entanglement when the modes interact with a classically correlated field.