Zero-dynamics principle for perfect quantum memory in linear networks

Naoki Yamamoto, Matthew R. James

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


In this paper, we study a general linear networked system that contains a tunable memory subsystem; that is, it is decoupled from an optical field for state transportation during the storage process, while it couples to the field during the writing or reading process. The input is given by a single photon state or a coherent state in a pulsed light field. We then completely and explicitly characterize the condition required on the pulse shape achieving the perfect state transfer from the light field to the memory subsystem. The key idea to obtain this result is the use of zero-dynamics principle, which in our case means that, for perfect state transfer, the output field during the writing process must be a vacuum. A useful interpretation of the result in terms of the transfer function is also given. Moreover, a four-node network composed of atomic ensembles is studied as an example, demonstrating how the input field state is transferred to the memory subsystem and what the input pulse shape to be engineered for perfect memory looks like.

Original languageEnglish
Article number073032
JournalNew Journal of Physics
Publication statusPublished - 2014 Jul


  • atomic ensemble
  • control theory
  • decoherence-free subsystem
  • linear networks
  • quantum memory
  • quantum stochastic differential equation

ASJC Scopus subject areas

  • General Physics and Astronomy


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