Comparison and control of the robustness between quantum entanglement and quantum correlation in an open quantum system  

作　　者：嵇英华 胡菊菊 胡燕 

机构地区：[1]Department of Physics,Jiangxi Normal University [2]Key Laboratory of Photoelectronics and Telecommunication of Jiangxi Province

出　　处：《Chinese Physics B》2012年第11期79-84,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant No. 11164009)

摘　　要：revised manuscript received 30 April 2012） We investigate the influence of environmental decoherence on the dynamics of a coupled qubit system and quantum correlation. We analyse the relationship between concurrence and the degree of initial entanglement or the purity of initial quantum state, and also their relationship with quantum discord. The results show that the decrease of the purity of an initial quantum state can induce the attenuation of concurrence or quantum discord, but the attenuation of quantum discord is obviously slower than the concurrence＇s, correspondingly the survival time of quantum discord is longer. Further investigation reveals that the robustness of quantum discord and concurrence relies on the entanglement degree of the initial quantum state. The higher the degree of entanglement, the more robust the quantum discord is than concurrence. And the reverse is equally true. Birth and death happen to quantum discord periodically and a newborn quantum discord comes into being under a certain condition, so does the concurrence.revised manuscript received 30 April 2012） We investigate the influence of environmental decoherence on the dynamics of a coupled qubit system and quantum correlation. We analyse the relationship between concurrence and the degree of initial entanglement or the purity of initial quantum state, and also their relationship with quantum discord. The results show that the decrease of the purity of an initial quantum state can induce the attenuation of concurrence or quantum discord, but the attenuation of quantum discord is obviously slower than the concurrence＇s, correspondingly the survival time of quantum discord is longer. Further investigation reveals that the robustness of quantum discord and concurrence relies on the entanglement degree of the initial quantum state. The higher the degree of entanglement, the more robust the quantum discord is than concurrence. And the reverse is equally true. Birth and death happen to quantum discord periodically and a newborn quantum discord comes into being under a certain condition, so does the concurrence.

关 键 词：coupled qubits non-Markovian process ENTANGLEMENT quantum discord 

分 类 号：O431.2[机械工程—光学工程]