中国物理B ›› 2013, Vol. 22 ›› Issue (7): 70302-070302.doi: 10.1088/1674-1056/22/7/070302

• GENERAL • 上一篇    下一篇

Non-Markovian decoherent quantum walks

薛鹏a, 张永生b   

  1. a Department of Physics, Southeast University, Nanjing 211189, China;
    b Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:2012-12-11 修回日期:2013-02-28 出版日期:2013-06-01 发布日期:2013-06-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10974192, 11004029, and 11174052), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK2010422), the Ph.D. Program of the Ministry of Education of China, the Excellent Young Teachers Program of Southeast University, China, and the National Basic Research Development Program of China (Grant No. 2011CB921203).

Non-Markovian decoherent quantum walks

Xue Peng (薛鹏)a, Zhang Yong-Sheng (张永生)b   

  1. a Department of Physics, Southeast University, Nanjing 211189, China;
    b Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
  • Received:2012-12-11 Revised:2013-02-28 Online:2013-06-01 Published:2013-06-01
  • Contact: Xue Peng E-mail:gnep.eux@gmail.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10974192, 11004029, and 11174052), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK2010422), the Ph.D. Program of the Ministry of Education of China, the Excellent Young Teachers Program of Southeast University, China, and the National Basic Research Development Program of China (Grant No. 2011CB921203).

摘要: Quantum walk acts obviously different from its classical counterpart, but the decoherence will lessen and close the gap between them. To understand this process, it is necessary to investigate the evolution of the quantum walk under different situations of decoherence. In this article, we study a non-Markovian decoherent quantum walk on a line. In the short time regime, the behavior of the walk deviates from both idea quantum walks and classical random walks. The position variance as a measure of the quantum-walk collapses and revivals for a short time and tends to have a linear relation with time, that is the walker's behavior shows a diffusive spread in the long time limit, which is caused by the non-Markovian dephasing affecting on quantum correlations between the quantum walker and his coin. We also study both quantum discord and measurement-induced disturbance as measures of quantum correlations and observe that both collapse and revival in the short time regime and tend to be zero in the long time limit. Therefore, the quantum walk with a non-Markovian decoherence tends to diffusive spreading behavior in the long time limit, while in the short time regime, it oscillates between a ballistic and diffusive spreading behavior, and the quantum correlation collapses and revivals due to the memory effect.

关键词: non-Markovian decohernece, quantum walks, quantum correlations

Abstract: Quantum walk acts obviously different from its classical counterpart, but the decoherence will lessen and close the gap between them. To understand this process, it is necessary to investigate the evolution of the quantum walk under different situations of decoherence. In this article, we study a non-Markovian decoherent quantum walk on a line. In the short time regime, the behavior of the walk deviates from both idea quantum walks and classical random walks. The position variance as a measure of the quantum-walk collapses and revivals for a short time and tends to have a linear relation with time, that is the walker's behavior shows a diffusive spread in the long time limit, which is caused by the non-Markovian dephasing affecting on quantum correlations between the quantum walker and his coin. We also study both quantum discord and measurement-induced disturbance as measures of quantum correlations and observe that both collapse and revival in the short time regime and tend to be zero in the long time limit. Therefore, the quantum walk with a non-Markovian decoherence tends to diffusive spreading behavior in the long time limit, while in the short time regime, it oscillates between a ballistic and diffusive spreading behavior, and the quantum correlation collapses and revivals due to the memory effect.

Key words: non-Markovian decohernece, quantum walks, quantum correlations

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

  • 03.67.Mn
03.65.Ta (Foundations of quantum mechanics; measurement theory) 05.40.Fb (Random walks and Levy flights) 03.67.Ac (Quantum algorithms, protocols, and simulations)