中国物理B ›› 2012, Vol. 21 ›› Issue (10): 100310-100310.doi: 10.1088/1674-1056/21/10/100310

• GENERAL • 上一篇    下一篇

Control of purity and entanglement for two spatially two-separated qubits via phase damping

A. S. F. Obadaa, H. A. Hessianb c, A. B. A. Mohamedb d, M. Hashemb   

  1. a Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt;
    b Faculty of Science, Assiut University, Assiut, Egypt;
    c Faculty of Science, Al-Baha University, Al-Baha, Saudi Arabia;
    d Al-Aflaj Community College, Salman Bin Abdulaziz University Al-Aflaj, Saudi Arabia
  • 收稿日期:2011-12-11 修回日期:2012-05-18 出版日期:2012-09-01 发布日期:2012-09-01

Control of purity and entanglement for two spatially two-separated qubits via phase damping

A. S. F. Obadaa, H. A. Hessianb c, A. B. A. Mohamedb d, M. Hashemb   

  1. a Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt;
    b Faculty of Science, Assiut University, Assiut, Egypt;
    c Faculty of Science, Al-Baha University, Al-Baha, Saudi Arabia;
    d Al-Aflaj Community College, Salman Bin Abdulaziz University Al-Aflaj, Saudi Arabia
  • Received:2011-12-11 Revised:2012-05-18 Online:2012-09-01 Published:2012-09-01
  • Contact: M. Hashem E-mail:mostafa_qbit@yahoo.com

摘要: Control of purity and entanglement of two two-qubits dispersively coupled to a field with a reservoir are investigated. Initially the qubits are entangled, while the field is either in a coherent state or a statistical mixture of two coherent states. For an alternative entanglement measure we calculate the negativity of the eigenvalues of the partially transposed density matrix. A measure related to the mutual entropy, namely the index of entropy, is employed to measure the entanglement. Its results agree well with the negativity. It is found that the entanglement and purity have strong sensitivity to phase damping. The asymptotic behaviour of the states of the field, the two two-qubits, and the total system fall into mixed states.

关键词: entanglement, phase damping, purity, separated qubits

Abstract: Control of purity and entanglement of two two-qubits dispersively coupled to a field with a reservoir are investigated. Initially the qubits are entangled, while the field is either in a coherent state or a statistical mixture of two coherent states. For an alternative entanglement measure we calculate the negativity of the eigenvalues of the partially transposed density matrix. A measure related to the mutual entropy, namely the index of entropy, is employed to measure the entanglement. Its results agree well with the negativity. It is found that the entanglement and purity have strong sensitivity to phase damping. The asymptotic behaviour of the states of the field, the two two-qubits, and the total system fall into mixed states.

Key words: entanglement, phase damping, purity, separated qubits

中图分类号:  (Entanglement measures, witnesses, and other characterizations)

  • 03.67.Mn
03.65.Vf (Phases: geometric; dynamic or topological) 03.65.Yz (Decoherence; open systems; quantum statistical methods)