Experimental Asynchronous Measurement-Device-Independent Quantum Cryptographic Conferencing

Abstract:The quantum cryptographic conferencing (QCC) protocol, which distributes identical secure keys to user groups, is a crucial component of the quantum network. Previous experimental works have implemented the measurement-device-independent (MDI) QCC, of which the key rate in an N-user network scales as $R\sim O(\eta^N)$. Building on the MDI QCC protocol, the asynchronous MDI QCC protocol theoretically integrates the mode-pairing scheme into QCC, significantly boosting the key rate to $R\sim O(\eta)$ in the ideal case, which is independent of the number of users, thus demonstrating greater application potential. Experimentally, in this Letter, we implement the three-user asynchronous MDI QCC network without phase locking by adopting the fast Fourier transform-based frequency difference estimation and the phase drift compensation technique. Finally, we achieve a key rate of about $4.470\times 10^{-9}$ bits per pulse under a maximum overall loss of about 59.6 dB. This Letter provides a scalable solution for the development of large-scale quantum communication networks in the future.

Quantum Physics (quant-ph); Optics (physics.optics)

arXiv:2602.20927 [quant-ph]

(or arXiv:2602.20927v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2602.20927 Focus to learn more arXiv-issued DOI via DataCite

Phys. Rev. Lett. 137, 120802 (2026)

https://doi.org/10.1103/k9k1-6281 Focus to learn more DOI(s) linking to related resources

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