中国物理B ›› 2011, Vol. 20 ›› Issue (8): 80302-080302.doi: 10.1088/1674-1056/20/8/080302

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Entanglement dynamics of two qubits coupled by Heisenberg XY interaction under a nonuniform magnetic field in a spin bath

祁义红1, 周凤雪2, 张理达2, 钮月萍2, 张敬涛2, 龚尚庆3   

  1. (1)Department of Physics, East China University of Science and Technology, Shanghai 200237, China; (2)State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; (3)State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; Department of Physics, East China University of Science and Technology, Shanghai 200237, China
  • 收稿日期:2011-02-24 修回日期:2011-03-16 出版日期:2011-08-15 发布日期:2011-08-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10874194, 60978013, and 60921004) and the International Cooperation Program from Science and Technology Commission of Shanghai Municipality (Grant No. 10530704800).

Entanglement dynamics of two qubits coupled by Heisenberg XY interaction under a nonuniform magnetic field in a spin bath

Zhou Feng-Xue(周凤雪)a), Zhang Li-Da(张理达) a), Qi Yi-Hong(祁义红)b), Niu Yue-Ping(钮月萍)a)†, Zhang Jing-Tao(张敬涛)a), and Gong Shang-Qing(龚尚庆) a)b)‡   

  1. a State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; b Department of Physics, East China University of Science and Technology, Shanghai 200237, China
  • Received:2011-02-24 Revised:2011-03-16 Online:2011-08-15 Published:2011-08-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10874194, 60978013, and 60921004) and the International Cooperation Program from Science and Technology Commission of Shanghai Municipality (Grant No. 10530704800).

摘要: This paper investigates the entanglement dynamics of a Heisenberg XY model for a two-spin system in the presence of a nonuniform magnetic field. The master equations and the concurrence evolution equations for the initial α state are derived and analysed. It is shown that for the symmetric initial α state, only the nonuniform field can play a role in entanglement dynamics while the uniform field and the bath will not play such a role. For the asymmetric α state, the nonuniform field leads to the beat pattern oscillation of the concurrence evolution. The inhomogeneity of the field can enhance the entanglement by suppressing the decoherence effects of both the spin—orbit interaction and the spin bath.

关键词: quantum entanglement, decoherence, qubits, Heisenberg model

Abstract: This paper investigates the entanglement dynamics of a Heisenberg XY model for a two-spin system in the presence of a nonuniform magnetic field. The master equations and the concurrence evolution equations for the initial α state are derived and analysed. It is shown that for the symmetric initial α state, only the nonuniform field can play a role in entanglement dynamics while the uniform field and the bath will not play such a role. For the asymmetric α state, the nonuniform field leads to the beat pattern oscillation of the concurrence evolution. The inhomogeneity of the field can enhance the entanglement by suppressing the decoherence effects of both the spin—orbit interaction and the spin bath.

Key words: quantum entanglement, decoherence, qubits, Heisenberg model

中图分类号:  (Entanglement and quantum nonlocality)

  • 03.65.Ud
03.67.Mn (Entanglement measures, witnesses, and other characterizations) 42.50.Dv (Quantum state engineering and measurements)