Quantum Memory with a Single Photon in a Cavity
Xavier Maı̂tre, E. W. Hagley, Gilles Nogues, C. Wunderlich, P. Goy, M. Brune, J. M. Raimond, S. Haroche · Physical Review Letters · 1997
The quantum information carried by a two-level atom was transferred to a high- $Q$ cavity and, after a delay, to another atom. We realized in this 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 corresponding to the decay of the field intensity or amplitude at the single photon level. This experiment implements a step essential for quantum information processing operations.