Photon-Photon Entanglement with a Single Trapped Atom
Physical Review Letters, 102 (3):
030501+ (2009)DOI: 10.1103/physrevlett.102.030501
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.