QUANTUM MEMORY WITH A SINGLE-PHOTON IN A CAVITY

The quantum information carried by a two-level atom was transferred to a high-e cavity and, after a delay, to another atom. We realized in t his way a quantum memory made of a field in a superposition of 0 and 1 photon Fock states. We measured the ''holding time'' of this memory c orresponding to the decay of the field intensity or amplitude at the s ingle photon level. This experiment implements a step essential for qu antum information processing operations.