A scheme for entangling distant atoms is realized, as proposed in the seminal paper by Cabrillo et al. [Phys. Rev. A 59, 1025 (1999)]. The protocol is based on quantum interference and detection of a single photon scattered from two effectively one meter distant laser-cooled and trapped atomic ions. The detection of a single photon heralds entanglement of two internal states of the trapped ions with high rate and with a fidelity limited mostly by atomic motion. Control of the entangled state phase is demonstrated by changing the path length of the single-photon interferometer.
@article{arxiv.1207.5468,
title = {Atom-atom entanglement by single-photon detection},
author = {L. Slodička and G. Hétet and N. Röck and P. Schindler and M. Hennrich and R. Blatt},
journal= {arXiv preprint arXiv:1207.5468},
year = {2015}
}