Quantum Logic with Cavity Photons From Single Atoms

We demonstrate quantum logic using narrow linewidth photons that are produced with an a-priory non-probabilistic scheme from a single 87Rb atom strongly coupled to a high- nesse cavity. We use a controlled-NOT gate integrated into a photonic chip to entangle these photons, and we observe non-classical correlations between photon detection events separated by periods exceeding the travel time across the chip by three orders of magnitude. This enables quantum technology that will use the properties of both narrowband single photon sources and integrated quantum photonics.