Continuous variable quantum key distribution in non-Markovian channels

TL;DR

This paper explores how non-Markovian properties in lossy channels can be exploited to improve security and eavesdropper detection in continuous variable quantum key distribution, especially at low transmission efficiencies.

Contribution

It introduces a coherent states QKD protocol leveraging non-Markovian features, achieving security against individual attacks even with very low transmission.

Findings

Non-Markovian channels can enhance QKD security.

The proposed protocol detects eavesdroppers along the transmission.

Security is maintained at arbitrarily low transmission levels.

Abstract

We address continuous variable quantum key distribution (QKD) in non-Markovian lossy channels and show how the non-Markovian features may be exploited to enhance security and/or to detect the presence and the position of an eavesdropper along the transmission line. In particular, we suggest a coherent states QKD protocol which is secure against individual attacks for arbitrarily low values of the overall transmission line. Our scheme relies on specific non-Markovian properties, and cannot be implemented in ordinary Markovian channels characterized by uniform losses.