Quantum entanglement via optical control of atom-atom interactions

Two-photon optical transitions combined with long-range dipole-dipole interactions can be used for the coherent manipulation of multiatom collective states. We show that it is possible to induce optical resonances accompanied by the generation of entangled superpositions of such atomic states. Resonances of this kind can be used to implement quantum logic gates using optically excited single atoms (impurities) in the condensed phase.