Non-Markovian disentanglement dynamics of two-qubit system in common environment

The disentanglement of a pair of identical qubits, sharing a dissipative environment, is investigated. We proposed a new non-Markovian analytical method to study the model, which takes into account the counter-rotating term in the qubit-environment interaction. It is shown that when the qubits sufficiently separate from each other, the model is equivalent to each subsystem interacts independently with its local environment. The effects of the dissipative environment and the interqubit distance on the time evolution of the concurrence for four bell states are examined in detail. And point out some new features appearing in the case of the two qubits close together.