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arXiv · 2404.18777

Quantum key distribution with displaced thermal states

Adam Walton·Anne Ghesquière·Benjamin Varcoe
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Abstract

Secret key exchange relies on the creation of correlated signals, serving as the raw resource for secure communication. Thermal states, exhibit Hanbury Brown and Twiss correlations, which offer a promising avenue for generating such signals. In this paper, we present an experimental implementation of a central broadcast thermal state quantum key distribution (QKD) protocol in the microwave region. Our objective is to showcase a straightforward method of QKD utilizing readily available broadcasting equipment. Unlike conventional approaches to thermal state QKD, we leverage displaced thermal states. These states enable us to share the output of a thermal source among Alice, Bob, and Eve via both waveguide channels and free space. Through measurement and conversion into bit strings, our protocol produces key-ready bit strings without the need for specialized equipment. By harnessing the inherent noise in thermal broadcasts, our setup facilitates the recovery of distinct bit strings by all parties involved.

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Adam Walton, Anne Ghesquière, Benjamin Varcoe. 2024-04-29. Quantum key distribution with displaced thermal states. https://doi.org/10.3390/e26060488

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