Circuit Quantum Electrodynamics: Coherent Coupling of a Single Photon to   a Cooper Pair Box
  Under appropriate conditions, superconducting electronic circuits behave quantum mechanically, with properties that can be designed and controlled at will. We have realized an experiment in which a superconducting two-level system, playing the role of an artificial atom, is strongly coupled to a single photon stored in an on-chip cavity. We show that the atom-photon coupling in this circuit can be made strong enough for coherent effects to dominate over dissipation, even in a solid state environment. This new regime of matter light interaction in a circuit can be exploited for quantum information processing and quantum communication. It may also lead to new approaches for single photon generation and detection. 
A. Wallraff, D. I. Schuster, A. Blais, L. Frunzio, R.-S. Huang, J.   Majer, S. Kumar, S. M. Girvin, and R. J. Schoelkopf