Toward scalable quantum computation with cavity QED systems
  We propose a scheme for quantum computing using high-Q cavities in which the qubits are represented by single cavity modes restricted in the space spanned by the two lowest Fock states. We show that single qubit operations and universal multiple qubit gates can be implemented using atoms sequentially crossing the cavities. 
V. Giovannetti, D. Vitali, P. Tombesi, and A. Ekert