中国物理B ›› 2007, Vol. 16 ›› Issue (1): 111-117.doi: 10.1088/1009-1963/16/1/020

• CLASSICAL AREAS OF PHENOMENOLOGY • 上一篇    下一篇

Entropy as a measure of the noise extent in a two-level quantum feedback controlled system

王涛波, 方卯发, 胡要花   

  1. College of Physics and Information Science, Hunan Normal University, Changsha 410081, China
  • 收稿日期:2006-05-27 修回日期:2006-07-05 出版日期:2007-02-01 发布日期:2007-02-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10374025).

Entropy as a measure of the noise extent in a two-level quantum feedback controlled system

Wang Tao-Bo(王涛波), Fang Mao-Fa(方卯发)†, and Hu Yao-Hua(胡要花)   

  1. College of Physics and Information Science, Hunan Normal University, Changsha 410081, China
  • Received:2006-05-27 Revised:2006-07-05 Online:2007-02-01 Published:2007-02-01
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10374025).

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摘要： By introducing the von Neumann entropy as a measure of the extent of noise, this paper discusses the entropy evolution in a two-level quantum feedback controlled system. The results show that the feedback control can induce the reduction of the degree of noise, and different control schemes exhibit different noise controlling ability, the extent of the reduction also related with the position of the target state on the Bloch sphere. It is shown that the evolution of entropy can provide a real time noise observation and a systematic guideline to make reasonable choice of control strategy.

Abstract: By introducing the von Neumann entropy as a measure of the extent of noise, this paper discusses the entropy evolution in a two-level quantum feedback controlled system. The results show that the feedback control can induce the reduction of the degree of noise, and different control schemes exhibit different noise controlling ability, the extent of the reduction also related with the position of the target state on the Bloch sphere. It is shown that the evolution of entropy can provide a real time noise observation and a systematic guideline to make reasonable choice of control strategy.

Key words: quantum entropy, quantum feedback

中图分类号:  (Thermodynamic functions and equations of state)

  • 05.70.Ce
03.65.Fd (Algebraic methods) 42.50.Lc (Quantum fluctuations, quantum noise, and quantum jumps)