A proposal for an optical implementation of a universal quantum phase gate

Large optical nonlinearities occurring in a coherently prepared atomic system are shown to produce phase shifts of order pi. Such an effect may be observed in ultracold rubidium atoms where it could be feasibly exploited toward the realization of a polarization phase gate

Scheme for a quantum phase gate based on electromagnetic induced transparency

We present a scheme for the experimental realization of a quantum phase gate acting on the polarization degree of freedom of traveling single photon wave-packets. The scheme exploits the giant Kerr nonlinearities that can be achieved in dense atomic media showing electromagnetically induced transparency, and it may be useful in a variety of quantum communication schemes