Improving the maximum transmission distance of continuous-variable quantum key distribution using a noiseless amplifier

TL;DR

This paper demonstrates that a linear noiseless amplifier can significantly extend the maximum transmission distance of continuous-variable quantum key distribution over noisy channels, by increasing tolerable losses.

Contribution

The study introduces a method to arbitrarily increase transmission distance in CV-QKD using a noiseless amplifier with specific gain settings.

Findings

Noiseless amplifier with gain g increases maximum tolerable losses by 1/g^2.

The protocol uses amplitude and phase modulated coherent states with reverse reconciliation.

Maximum transmission distance can be arbitrarily extended with this approach.

Abstract

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.