Complete elimination of information leakage in continuous-variable quantum communication channels

TL;DR

This paper introduces a quantum communication protocol that completely prevents information leakage in lossy channels by encoding into a restricted Gaussian alphabet of squeezed states, with both theoretical and experimental validation.

Contribution

It demonstrates a method to eliminate information leakage in lossy quantum channels using a specific encoding scheme, advancing secure quantum communication.

Findings

Holevo information between eavesdropper and receiver is zero in lossy channels

Protocol is validated both theoretically and experimentally

Potential to extend secure quantum key distribution distances

Abstract

In all lossy communication channels realized to date, information is inevitably leaked to a potential eavesdropper. Here we present a communication protocol that does not allow for any information leakage to a potential eavesdropper in a purely lossy channel. By encoding information into a restricted Gaussian alphabet of squeezed states we show, both theoretically and experimentally, that the Holevo information between the eavesdropper and the intended recipient can be exactly zero in a purely lossy channel while minimized in a noisy channel. This result is of fundamental interest, but might also have practical implications in extending the distance of secure quantum key distribution.