Entanglement Dynamics of a Dissipative Two-qubit System Under the Influence of a Global Environment

摘要

In this paper we propose a two-qubit system exposed to a common thermal reservoir as the source of dissipation. Starting from the master equation, specially its dissipator part, we find its explicit solution through which we investigate the time evolution of entanglement between the two qubits via concurrence measure by considering different initial entangled states. Our results show that the system can be found in Markovian and non-Markovian regimes depending on the involved parameters. In the Markovian regime, the amount of entanglement permanently deceases and therefore the two-qubit system is finally found in a separable state. In the other hand, in non-Markovian regime, the two-qubit system exchanges its entanglement with environment in such a way that it can recover its entanglement loss as time passes. In this case, the system undergoes a death of entanglement at some intervals of time, however, then restores its entanglement and gradually reaches to a maximally stable entangled state. Restoring of entanglement is a remarkable outcome of global environment in comparison with its local counterpart. Also, the amount of entanglement can be adjusted by choosing appropriate parameters involved in the proposed model such as thermal excitation number as well as the initial condition of the two-qubit state of system.