Quantum state discrimination

Stephen M. Barnett, Sarah Croke

Research output: Contribution to journalArticlepeer-review

200 Citations (Scopus)


It is a fundamental consequence of the superposition principle for quantum states that there must exist nonorthogonal states, that is, states that, although different, have a nonzero overlap. This finite overlap means that there is no way of determining with certainty in which of two such states a given physical system has been prepared. We review the various strategies that have been devised to discriminate optimally between nonorthogonal states and some of the optical experiments that have been performed to realize these.
Original languageEnglish
Pages (from-to)238-278
Number of pages41
JournalAdvances in Optics and Photonics
Issue number2
Publication statusPublished - 1 Apr 2009


  • quantum communications
  • quantum information
  • quantum processing

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