Sudden death and robustness of quantum correlations in the weak- or strong-coupling regime

Abstract

We study the dynamics of quantum discord and entanglement of two entangled two-level atoms within two isolated and dissipative cavities in the weak- or strong-coupling regime. The quantum entanglement are measured by concurrence and relative entropy. The quantum discord of two atoms based on quantum mutual information and relative entropy are also calculated. In the weak-coupling regime, the sudden death of quantum discord and entanglement of two atoms can occur simultaneously within a short interaction time. When the interaction time is long, quantum discord and entanglement of two atoms could be partially preserved due to the long-lived nature of quantum discord and entanglement. However, in the strong-coupling regime, there is no sudden death of quantum discord though the entanglement sudden death phenomenon occurs. In addition, we observe that entanglement and discord will be destroyed eventually when the atom-field interactions are strong. We also address the issue of experimental realization briefly.