  We propose a scheme to generate two-photon, two-atom, or atom-photon
entangledstates with a coupled system of two cavities. In our scheme, two
cavity photonsare exchanged by the direct inter-cavity coupling, while atoms in
the cavitiessimply play the role of generating and probing them. By virtue of
the highefficiency of atomic state measurement, this method enables the
realization ofefficient heralded entanglement generation robust against photon
loss, whichgreatly facilitates applications in quantum information processing.
