Atom-Photon Entanglement
  We report the observation of entanglement between a single trapped atom and a single photon at a wavelength suitable for low-loss communication over large distances, thereby achieving a crucial step towards long range quantum networks. To verify the entanglement we introduce a single atom state analysis. This technique is used for full state tomography of the atom-photon qubit-pair. The detection efficiency and the entanglement fidelity are high enough to allow in a next step the generation of entangled atoms at large distances, ready for a final loophole-free Bell experiment. 
Juergen Volz, Markus Weber, Daniel Schlenk, Wenjamin Rosenfeld,   Johannes Vrana, Karen Saucke, Christian Kurtsiefer, and Ha...