title: Photon-photon entanglement with a single trapped atom.
abstract: An experiment is performed where a single rubidium atom trapped within a high-finesse optical cavity emits two independently triggered entangled photons. The entanglement is mediated by the atom and is characterized both by a Bell inequality violation of S=2.5, as well as full quantum-state tomography, resulting in a fidelity exceeding F=90%. The combination of cavity-QED and trapped atom techniques makes our protocol inherently deterministic--an essential step for the generation of scalable entanglement between the nodes of a distributed quantum network.
authors.affiliation: Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Weber
authors.forename: H P
authors.initials: HP
authors.lastname: Specht
authors.forename: T
authors.initials: T
authors.lastname: Müller
authors.forename: J
authors.initials: J
authors.lastname: Bochmann
authors.forename: M
authors.initials: M
authors.lastname: Mücke
authors.forename: D L
authors.initials: DL
authors.lastname: Moehring
authors.forename: G
authors.initials: G
authors.lastname: Rempe