Quantum feedback networks and control: A brief survey

Guofeng Zhang, Matthew R. James

Research output: Journal article publicationReview articleAcademic researchpeer-review

68 Citations (Scopus)


The purpose of this paper is to provide a brief review of some recent developments in quantum feedback networks and control. A quantum feedback network (QFN) is an interconnected system consisting of open quantum systems linked by free fields and/or direct physical couplings. Basic network constructs, including series connections as well as feedback loops, are discussed. The quantum feedback network theory provides a natural framework for analysis and design. Basic properties such as dissipation, stability, passivity and gain of open quantum systems are discussed. Control system design is also discussed, primarily in the context of open linear quantum stochastic systems. The issue of physical realizability is discussed, and explicit criteria for stability, positive real lemma, and bounded real lemma are presented. Finally for linear quantum systems, coherent H∞and LQG control are described.
Original languageEnglish
Pages (from-to)2200-2214
Number of pages15
JournalChinese Science Bulletin
Issue number18
Publication statusPublished - 1 Jun 2012


  • H control ∞
  • LQG control
  • open quantum systems
  • physical realizability
  • quantum feedback networks

ASJC Scopus subject areas

  • General


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