We analyze optical binary communication assisted by entanglement and show that: i) ideal entangled channels have smaller error probability than ideal single-mode coherent channels if the photon number of the channel is larger than one; ii) realistic entangled channels with heterodyne receivers have smaller error probability than ideal single-mode coherent channels if the photon number of the channel is larger than a threshold of about five photons.
@article{arxiv.quant-ph/0210014,
title = {Binary communication in entangled channels},
author = {Matteo G A Paris},
journal= {arXiv preprint arXiv:quant-ph/0210014},
year = {2007}
}