Quantum Secrecy in Thermal States

TL;DR

This paper demonstrates quantum key distribution using thermal states generated by low power sources, exploiting quantum correlations via the Hanbury Brown and Twiss effect, and shows it is feasible even in noisy environments.

Contribution

It introduces a new protocol for quantum secrecy using thermal states and experimentally compares laser and thermal regimes for key distribution.

Findings

Quantum secrecy is achievable with thermal states.

Experimental key rates are demonstrated in both laser and thermal regimes.

Quantum correlations enable secure communication in high noise conditions.

Abstract

We propose to perform quantum key distribution using quantum correlations occurring within thermal states produced by low power sources such as LED's. These correlations are exploited through the Hanbury Brown and Twiss effect. We build an optical central broadcast protocol using a superluminescent diode which allows switching between laser and thermal regimes, enabling us to provide experimental key rates in both regimes. We provide a theoretical analysis and show that quantum secrecy is possible, even in high noise situations.