Photons are central to quantum technologies, with photonic qubits offering a promising platform for quantum communication. Semiconductor quantum dots stand out for their ability to generate single photons on demand, a key capability for enabling long-distance quantum networks. In this work, we utilize high-purity single-photon sources based on self-assembled InAs(Ga)As quantum dots as quantum information carriers. We demonstrate that such on-demand single photons can generate quantum contextuality. This capability enables a novel protocol for semi-device-independent quantum key distribution over free-space channels. Crucially, our method does not require ideal or perfectly projective measurements, opening a new pathway for robust and practical quantum communication.
@article{arxiv.2510.12761,
title = {Contextuality-based quantum key distribution with deterministic single-photon sources},
author = {Yu Meng and Debashis Saha and Mikkel Thorbjørn Mikkelsen and Clara Henke and Ying Wang and Nikolai Bart and Arne Ludwig and Peter Lodahl and Adán Cabello and Leonardo Midolo},
journal= {arXiv preprint arXiv:2510.12761},
year = {2025}
}