Eur. Phys. J. D 64, 565-571 (2011)
https://doi.org/10.1140/epjd/e2011-20195-y

Regular Article

Dynamics of quantum discord for two correlated qubits in two independent reservoirs at finite temperature

¹ Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Department of Physics, Hunan Normal University, Changsha 410081, P.R. China
² Department of Mathematics and Science, Hunan First Normal University, Changsha 410205, P.R. China

^a e-mail: lmkuang@hunnu.edu.cn

Received: 3 April 2011
Received in final form: 7 June 2011
Published online: 4 October 2011

Abstract

We investigate dynamics of quantum discord (QD) for two initially-correlated qubits in two independent Ohmic reservoirs at finite temperature. It is indicated that the QD changes from a constant regime to a decaying regime when the two qubits are initially prepared in X-type quantum states. In the QD constant regime, the initial QD can be preserved despite decoherence in the system. It is found that temperature difference between two reservoirs significantly affects the preservation duration (PD) of the initial QD. We show that it is possible to enhance the preservation duration by properly choosing system parameters of the two qubits and reservoir parameters. Physically, it is found that the PD of the QD can reflect the temperature inhomogeneity of the non-equilibrium system which consists of the two qubits and their reservoirs.