Quantum measurements of atoms using cavity QED

Adetunmise C. Dada, Erika Andersson, Martin L. Jones, Vivien M. Kendon, Mark S. Everitt

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)
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Generalized quantum measurements are an important extension of projective or von Neumann measurements in that they can be used to describe any measurement that can be implemented on a quantum system. We describe how to realize two nonstandard quantum measurements using cavity QED. The first measurement optimally and unambiguously distinguishes between two nonorthogonal quantum states. The second example is a measurement that demonstrates superadditive quantum coding gain. The experimental tools used are single-atom unitary operations effected by Ramsey pulses and two-atom Tavis-Cummings interactions. We show how the superadditive quantum coding gain is affected by errors in the field-ionization detection of atoms and that even with rather high levels of experimental imperfections, a reasonable amount of superadditivity can still be seen. To date, these types of measurements have been realized only on photons. It would be of great interest to have realizations using other physical systems. This is for fundamental reasons but also since quantum coding gain in general increases with code word length, and a realization using atoms could be more easily scaled than existing realizations using photons.
Original languageEnglish
Article number042339
Number of pages10
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number4
Publication statusPublished - 29 Apr 2011


  • cavity QED
  • code-words
  • experimental imperfections
  • physical systems
  • quantum coding
  • quantum measurement
  • quantum state
  • quantum system
  • superadditivity
  • unitary operation
  • Von Neumann measurement
  • atoms
  • coding errors
  • photons
  • quantum electronics
  • quantum optics
  • measurements


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