Multi-mode CV-QKD with Noiseless Attenuation and Amplification

TL;DR

This paper introduces an improved multi-mode CV-QKD protocol utilizing noiseless attenuation and amplification, enhancing transmission distance and noise tolerance in satellite-to-ground quantum communication.

Contribution

It proposes a novel multi-mode CV-QKD protocol with combined noiseless attenuation and amplification, extending capabilities beyond single-mode systems.

Findings

Noiseless amplification increases transmission distance.

Adding noiseless attenuation further enhances key rate.

Protocol improves noise tolerance in satellite channels.

Abstract

In this work we study the use of noiseless attenuation and noiseless amplification, in terms of multi-mode Continuous-Variable (CV) Quantum Key Distribution (QKD) over satellite-to-ground channels. We propose an improved multi-mode CV-QKD protocol where noiseless attenuation and noiseless amplification operations are applied at the transmitter and the receiver, respectively. Our results show that consistent with single-mode CV-QKD, the noiseless amplification operation, when applied at the receiver, can increase the transmission distance and the channel noise tolerance of multi-mode CV-QKD. Different from single-mode CV-QKD, in multi-mode CV-QKD the key rate improvement offered by noiseless amplification can be further enhanced by adding noiseless attenuation at the transmitter.