中国物理B ›› 2019, Vol. 28 ›› Issue (6): 60303-060303.doi: 10.1088/1674-1056/28/6/060303

• GENERAL • 上一篇    下一篇

Steady-state entanglement and heat current of two coupled qubits in two baths without rotating wave approximation

Mei-Jiao Wang(王美姣), Yun-Jie Xia(夏云杰)   

  1. 1 College of Physics and Engineering, Qufu Normal University, Qufu 273165, China;
    2 Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Qufu Normal University, Qufu 273165, China
  • 收稿日期:2019-01-21 修回日期:2019-03-11 出版日期:2019-06-05 发布日期:2019-06-05
  • 通讯作者: Yun-Jie Xia E-mail:yjxia@qfnu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 61675115 and 11704221).

Steady-state entanglement and heat current of two coupled qubits in two baths without rotating wave approximation

Mei-Jiao Wang(王美姣)1,2, Yun-Jie Xia(夏云杰)1,2   

  1. 1 College of Physics and Engineering, Qufu Normal University, Qufu 273165, China;
    2 Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Qufu Normal University, Qufu 273165, China
  • Received:2019-01-21 Revised:2019-03-11 Online:2019-06-05 Published:2019-06-05
  • Contact: Yun-Jie Xia E-mail:yjxia@qfnu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 61675115 and 11704221).

摘要: We study the steady-state entanglement and heat current of two coupled qubits, in which two qubits are connected with two independent heat baths (IHBs) or two common heat baths (CHBs). We construct the master equation in the eigenstate representation of two coupled qubits to describe the dynamics of the total system and derive the solutions in the steady-state with stronger coupling regime between two qubits than qubit-baths. We do not make the rotating wave approximation (RWA) for the qubit-qubit interaction, and so we are able to investigate the behaviors of the system in both the strong coupling regime and the weak coupling regime, respectively. In an equilibrium bath, we find that the entanglement decreases with the bath temperature and energy detuning increasing under the strong coupling regime. In the weak coupling regime, the entanglement increases with coupling strength increasing and decreases with the bath temperature and energy detuning increasing. In a nonequilibrium bath, the entanglement without RWA is useful for entanglement at lower temperatures. We also study the heat currents of the two coupled qubits and their variations with the energy detuning, coupling strength and low temperature. In the strong (weak) coupling regime, the heat current increases (decreases) with coupling strength increasing when the temperature of one bath is lower (higher) than the other, and the energy detuning leads to a positive (negative) effect when the temperature is low (high). In the weak coupling regime, the variation trend of heat current is opposite to that of coupling strength for the IHB case and the CHB case.

关键词: steady-state entanglement, equilibrium and nonequilibrium baths, heat current, rotating wave approximation

Abstract: We study the steady-state entanglement and heat current of two coupled qubits, in which two qubits are connected with two independent heat baths (IHBs) or two common heat baths (CHBs). We construct the master equation in the eigenstate representation of two coupled qubits to describe the dynamics of the total system and derive the solutions in the steady-state with stronger coupling regime between two qubits than qubit-baths. We do not make the rotating wave approximation (RWA) for the qubit-qubit interaction, and so we are able to investigate the behaviors of the system in both the strong coupling regime and the weak coupling regime, respectively. In an equilibrium bath, we find that the entanglement decreases with the bath temperature and energy detuning increasing under the strong coupling regime. In the weak coupling regime, the entanglement increases with coupling strength increasing and decreases with the bath temperature and energy detuning increasing. In a nonequilibrium bath, the entanglement without RWA is useful for entanglement at lower temperatures. We also study the heat currents of the two coupled qubits and their variations with the energy detuning, coupling strength and low temperature. In the strong (weak) coupling regime, the heat current increases (decreases) with coupling strength increasing when the temperature of one bath is lower (higher) than the other, and the energy detuning leads to a positive (negative) effect when the temperature is low (high). In the weak coupling regime, the variation trend of heat current is opposite to that of coupling strength for the IHB case and the CHB case.

Key words: steady-state entanglement, equilibrium and nonequilibrium baths, heat current, rotating wave approximation

中图分类号:  (Decoherence; open systems; quantum statistical methods)

  • 03.65.Yz
05.30.-d (Quantum statistical mechanics) 05.70.Ln (Nonequilibrium and irreversible thermodynamics)