Performance analysis of continuous-variable quantum key distribution using non-Gaussian states

TL;DR

This paper investigates the performance of a continuous-variable quantum key distribution protocol using non-Gaussian states, specifically photon-added and photon-subtracted coherent states, demonstrating improved security and robustness in noisy environments.

Contribution

It introduces a discrete modulation protocol with non-Gaussian states and shows it outperforms Gaussian protocols under various environmental conditions.

Findings

PASCS always outperform coherent states under same conditions

Noisier channels improve PASCS protocol performance

Protocol is advantageous in non-ideal, noisy environments

Abstract

In this study, we analyze the efficiency of a protocol with discrete modulation of continuous variable non-Gaussian states, the coherent states having one photon added and then one photon subtracted (PASCS). We calculate the secure key generation rate against collective attacks using the fact that Eve's information can be bounded based on the protocol with Gaussian modulation, which in turn is unconditionally secure. Our results for a four-state protocol show that the PASCS always outperforms the equivalent coherent states protocol under the same environmental conditions. Interestingly, we find that for the protocol using discrete-modulated PASCS, the noisier the line, the better will be its performance compared to the protocol using coherent states. Thus, our proposal proves to be advantageous for performing quantum key distribution in non-ideal situations.