Implementation of a quantum $\sqrt{\rm_{swap}}$ gate for two distant atoms trapped in separate cavities

We present a scheme to implement a quantum [Formula: see text] gate for two-atom trapped in distant cavities connected via an optical fiber. In the whole process, the atomic system, the cavity modes and the fiber are not excited ensuring that the operation is insensitive to atomic spontaneous emission, cavity decay and the fiber loss. This scheme is significant for distributed and scalable quantum computation.

Unconventional geometric phase gates for two distant atoms trapped in spatially separate cavities

In this paper, we propose a scheme for implementing an unconventional two-qubit geometric phase gate for two distant atoms trapped in cavities connected by an optical fiber. During the gate operation, the atoms are still in the ground states, while the cavity modes and fiber mode are displaced along a circle in the phase space. In this way, the system can acquire different geometric phases conditional upon the atomic states. We find that the operation of the geometric phase gate can be speeded up as the detuning between the cavity field and light fields decreases. Moreover, it is observed that the fidelity for the geometric phase gate is remarkably insensitive to the fluctuation of the detuning parameter. The effects of cavity decay and fiber loss on the gate have also been checked.