Entanglement experiments with single atoms and photons in a cavity

Tatjana Wilk

A single atom strongly coupled to a high-finesse optical-cavity is a versatile tool for quantum information processing. Utilized as a single-photon source, it allows one to generate single photons very efficiently in a well defined spatio-temporal mode. In a first experiment, polarization-control over the photons is shown. A time-resolved two-photon interference experiment proves the indistinguishability of these photons - required in various quantum information processing schemes. Moreover, in a second experiment, entanglement between the polarization of the emitted photon and the population of the atomic Zeeman levels is created. Subsequent state mapping of the atomic state onto another photon results in a pair of polarization-entangled photons emitted one after the other from the cavity. Although these schemes are in principle possible in free space, the cavity boosts the efficiency by several orders of magnitude.

S. Haroche

S. Haroche

S. Haroche, Alexia Auffèves, Tristan Meunier +5 more

Cavity QED experiments involving single- and multi-photon microwave fields and displaying atom-radiation entanglement will be described. These experiments reveal in a striking way the quantum nature of the field and its graininess.

Gerhard Rempe, M. Hijlkema, Axel Kuhn +4 more

We review recent experiments with single atoms strongly coupled to high-finesse optical cavities, highlighting deterministic schemes for the production of polarized single photons, the generation of an entanglement between a stationary atom and a flying photon, the mapping of a quantum state from an atom onto a photon, the emission of an entangled photon pair, and the generation of an up-to-half-a-minute long stream of single photons from one-and-the-same atom.

Joerg Bochmann, B. Weber, Holger Specht +6 more