We present here an all--optical scheme for the experimental realization of a quantum phase gate. It is based on the polarization degree of freedom of two travelling single photon wave-packets and exploits giant Kerr nonlinearities that can be attained in coherently driven ultracold atomic media.
@article{arxiv.quant-ph/0302070,
title = {Polarization qubit phase gate in driven atomic media},
author = {Carlo Ottaviani and David Vitali and Maurizio Artoni and Francesco Cataliotti and Paolo Tombesi},
journal= {arXiv preprint arXiv:quant-ph/0302070},
year = {2009}
}