System Identification for Passive Linear Quantum Systems

Madalin Guta, Naoki Yamamoto

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


System identification is a key enabling component for the implementation of quantum technologies, including quantum control. In this paper, we consider the class of passive linear input-output systems, and investigate several basic questions: 1) which parameters can be identified? 2) Given sufficient input-output data, how do we reconstruct the system parameters? 3) How can we optimize the estimation precision by preparing appropriate input states and performing measurements on the output? We show that minimal systems can be identified up to a unitary transformation on the modes, and systems satisfying a Hamiltonian connectivity condition called 'infecting' are completely identifiable. We propose a frequency domain design based on a Fisher information criterion, for optimizing the estimation precision for coherent input state. As a consequence of the unitarity of the transfer function, we show that the Heisenberg limit with respect to the input energy can be achieved using non-classical input states.

Original languageEnglish
Article number7130587
Pages (from-to)921-936
Number of pages16
JournalIEEE Transactions on Automatic Control
Issue number4
Publication statusPublished - 2016 Apr 1


  • Estimation
  • linear systems
  • quantum information and control
  • stochastic systems
  • system identification

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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