Virtual noiseless amplification and Gaussian post-selection in continuous-variable quantum key distribution

TL;DR

This paper demonstrates that virtual noiseless amplification and attenuation, simulated via Gaussian post-selection in data processing, can enhance the performance and security range of continuous-variable quantum key distribution without physical implementation.

Contribution

It introduces a method to simulate noiseless quantum operations through data post-processing, improving QKD performance without additional physical hardware.

Findings

Enhances secure range of QKD systems.

Increases tolerable excess noise levels.

Maintains Gaussian security proof benefits.

Abstract

The noiseless amplification or attenuation are two heralded filtering operations that enable respectively to increase or decrease the mean field of any quantum state of light with no added noise, at the cost of a small success probability. We show that inserting such noiseless operations in a transmission line improves the performance of continuous-variable quantum key distribution over this line. Remarkably, these noiseless operations do not need to be physically implemented but can simply be simulated in the data post-processing stage. Hence, virtual noiseless amplification or attenuation amounts to perform a Gaussian post-selection, which enhances the secure range or tolerable excess noise while keeping the benefits of Gaussian security proofs.