Heralded generation of entanglement with coupled cavities

We propose a scheme to generate two-photon, two-atom, or atom-photon entangled states with a coupled system of two cavities. In our scheme, two cavity photons are exchanged by the direct intercavity coupling, while atoms in the cavities simply generate and probe them. By virtue of the high efficiency of atomic state measurement, this method enables the realization of efficient heralded entanglement generation which is robust against photon loss, which greatly facilitates applications in quantum-information processing.