We show that the maximum transmission distance of continuous-variable quantum key distribution in presence of a Gaussian noisy lossy channel can be arbitrarily increased using a linear noiseless amplifier. We explicitly consider a protocol using amplitude and phase modulated coherent states with reverse reconciliation. We find that a noiseless amplifier with amplitude gain g can increase the maximum admissible losses by a factor 1/g^2.
@article{arxiv.1205.0959,
title = {Improving the maximum transmission distance of continuous-variable quantum key distribution using a noiseless amplifier},
author = {Rémi Blandino and Anthony Leverrier and Marco Barbieri and Jean Etesse and Philippe Grangier and Rosa Tualle-Brouri},
journal= {arXiv preprint arXiv:1205.0959},
year = {2012}
}