This experiment represents the first realization of conditional dynamics suitable for quantum logic with single photons.
Individual atoms serve as qubits with information encoded in the internal atomic state.
Computation proceeds by a series of one and two bit interactions between the atoms. Our investigation of optical systems is motivated in large measure by realistic prospects for the laboratory implementation of elementary quantum logic operations. Moreover, the systems that we propose to investigate should provide a powerful meeting ground for theory and experiment in terms of assessing the impact of dissipation, for testing various error correction protocols, and for implementing realistic simulations. A major advantage of our atom-cavity systems compared to other proposals for quantum logic is the ability to observe directly and efficiently the principal dissipative channel, namely the decay of the cavity field. To make the two qubits distinguishable, a small frequency offset between the two fields is introduced.