Sensitivity Analysis of Cascaded Quantum Feedback Amplifier

Yu Yokotera, Naoki Yamamoto

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Quantum amplifier is an essential device in quantum information processing. As in the classical (non-quantum) case, its characteristic uncertainty needs to be suppressed by feedback, and in fact such a control theory for a single quantum amplifier has recently been developed. This letter extends this result to the case of cascaded quantum amplifier. In particular, we consider two types of structures: the case where controlled amplifiers are connected in series, and the case where a single feedback control is applied to the cascaded amplifier. Then, we prove that the latter is better in the sense of sensitivity to the uncertainty. A detailed numerical simulation is given to show actual performance of these two feedback schemes.

Original languageEnglish
Article number8424461
Pages (from-to)156-161
Number of pages6
JournalIEEE Control Systems Letters
Issue number1
Publication statusPublished - 2019 Jan


  • Quantum information and control
  • robust control
  • stability of linear systems

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Control and Optimization


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