Device-independent quantum key distribution over 100 km with single atoms

Science 2026 Open access

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Authors: Bo-Wei Lu, Chao-Wei Yang, Run-Qi Wang, Boyang Gao, Yi-Zheng Zhen, Zhen‐Gang Wang, Jia-Kai Shi, Zhong-Qi Ren, Thomas Hahn, Ernest Y.-Z. Tan, Xiu-Ping Xie, Ming-Yang Zheng
+6 more Xiao Jiang, Jun Zhang, Feihu Xu, Q. J. Zhang, Xiao‐Hui Bao, Jian-Wei Pan
DOI: 10.1126/science.aec6243
Cited by: 13
References: 56

Abstract

Device-independent quantum key distribution (DI-QKD) is a key application of the quantum internet. We report the realization of DI-QKD between two single-atom nodes linked by 100-kilometer (km) fibers. To improve the entangling rate, single-photon interference is leveraged for entanglement heralding, and quantum frequency conversion is used to reduce fiber loss. A tailored Rydberg-based emission scheme suppresses the photon recoil effect on the atom without introducing noise. We achieved high-fidelity atom-atom entanglement and positive asymptotic key rates for fiber lengths up to 100 km. At 11 km, 1.2 million heralded Bell pairs were prepared over 624 hours, yielding an estimated extractable finite-size secure key rate of 0.112 bits per event against general attacks. Our results close the gap between proof-of-principle quantum network experiments and real-world applications.

Fields of Study & Subjects

Quantum Information and Cryptography Quantum Mechanics and Applications Cold Atom Physics and Bose-Einstein Condensates

Publication details

Journal / source
Science
Publisher
American Association for the Advancement of Science (AAAS)
Volume
391
Issue
6785
Pages
592–597
Publication date
5 February 2026
Language
EN