Implementation of a two-qubit controlled-U gate based on unconventional   geometric phase with a constant gating time
  We propose an alternative scheme to implement a two-qubits Controlled-U gate in the hybrid system atom-$CCA$ (coupled cavities array). Our scheme results in a constant gating time and, with an adjustable qubit-bus coupling (atom-resonator), one can specify a particular transformation $U$ on the target qubit. We believe that this proposal may open promising perspectives for networking quantum information processors and implementing distributed and scalable quantum computation. 
Bruno F. C. Yabu-uti and Jos\'e A. Roversi
quant-ph