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

• 来源期刊: 中国物理（英文版）
• 关键词: quantum entropy quantum feedback
• 年，卷（期）: 2007,（1）
• 页码范围: 111-117
• 页数: 7页
• 语种: 英文

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.