Manipulating and probing microwave fields in a cavity by quantum non-demolition photon counting

S. Haroche, I. Dotsenko, S. Deleglise, C. Sayrin, X. Zhou, S. Gleyzes, C. Guerlin, S. Kuhr, M. Brune, J-M Raimond

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We perform quantum non-demolition (QND) photon counting on a microwave field trapped in a very high Q superconducting cavity, employing circular Rydberg atoms as non-absorbing light probes. Beyond realizing fundamental tests of quantum measurement theory, we use this QND method to prepare non-classical Fock and Schrodinger cat states of the field and to reconstruct their Wigner functions. Monitoring the evolution of these functions provides a direct observation of the decoherence process. Quantum feedback procedures will enable us to steer the field towards target states and to protect them against decoherence.
Original languageEnglish
Article number014014
Number of pages7
JournalPhysica Scripta
Issue numberT137
Publication statusPublished - 1 Dec 2009


  • quantum mechanics
  • optics
  • molecular physics
  • microwave fileds
  • cavity
  • quantum optics
  • lasers

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