Quantum Discord of Coupling Qubits in Decoherence-Free Subspace and Squeezed Vacuum Reservoir

Abstract

We investigate the dynamical behavior of quantum discord for the coupling qubits that placed in squeezed vacuum reservoir and initially in decoherence-free subspace (DFS). The results show that the DFS for resisting the effects from environmental decoherence and disentanglement is not the DFS of quantum discord. We also find that under certain conditions, the quantum discord and entanglement perform completely inversely versus the squeezed parameters. The quantum discord is controlled by the squeezed parameters, especially in the initial stage of the evolution, the bigger the parameter is, and the longer the time of initial death will be.