Cavity QED, Entanglement and Mesoscopic Quantum Coherences

  • S. Haroche
  • J. M. Raimond
Conference paper


Cavity Quantum Electrodynamics1 studies the behaviour of an atom in a small “box” whose typical size is of the order of the characteristic atomic emission wavelength. In such a confined space, the field amplitude associated with vacuum fluctuations in a mode is large and the coupling of the atom with these fluctuations becomes very strong, leading to non-linear optical effects at a quite unusual scale. Manipulation of atom and field properties is then possible. Most strikingly, one can affect the field in the cavity by coupling it to a single atom which acts as a microscopic “index” altering the field phase or frequency1,2. A quantum control of the field becomes then feasible, since the single atom can be prepared in superposition of states corresponding to different index values. Among the fundamental experiments which are made possible by these novel field manipulation techniques, let us list Quantum Non Demolition detection of photons illustrating the measurement process1, 3, 4, demonstrations of quantum non-locality and the generation and study of mesoscopic coherences1, 4, 5, 6.


Photon Number Rydberg State Microwave Pulse Linear Superposition Rydberg Atom 
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Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • S. Haroche
    • 1
  • J. M. Raimond
    • 1
  1. 1.Département de Physique de l’Ecole Normale SuperieureLaboratoire Kastler BrosselParis CedexFrance

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