One Atom in an Optical Cavity: Entanglement and Applications to Quantum Computation

We propose a scheme to implement two-bit quantum phase gates and one-bit unitary gates by using the two-mode two-photon Jaynes--Cummings model. The entanglement between the atom and cavity is also investigated in the presence of phase decoherence. It is found that there is stationary entanglement that is sensitive with the detuning.