Device-independent quantum key distribution over 100 km with single atoms
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.
Authors
- J. L. Shi (ORCID: https://orcid.org/0009-0000-6832-523X)
- Chao-Wei Yang
- Zhen‐Gang Wang (ORCID: https://orcid.org/0000-0002-3361-6114)
- Xiao‐Hui Bao (ORCID: https://orcid.org/0000-0002-6721-3807)
- Jianyu Pan (ORCID: https://orcid.org/0000-0002-8777-0002)
- Q. J. Zhang
- Run-Qi Wang
- Y. Y. Ji (ORCID: https://orcid.org/0000-0003-1169-5250)
- Ernest Y.-Z. Tan (ORCID: https://orcid.org/0000-0003-4872-158X)
- Yi-Zheng Zhen (ORCID: https://orcid.org/0000-0002-7125-6922)
- Xiu-Ping Xie
- Bo-Wei Lu
- Ming-Yang Zheng (ORCID: https://orcid.org/0009-0005-9061-8852)
- Boyang Gao
- Thomas Hahn
- Feihu Xu
- Zhong-Qi Ren
- Jun Zhang
Institutions
- University of Science and Technology of China (CN)
- University of Waterloo (CA)
- National University of Singapore (SG)
- Hefei National Center for Physical Sciences at Nanoscale (CN)
- Jinan Institute of Quantum Technology (CN)
- Weizmann Institute of Science (IL)
Publication Details
- Journal
- Science
- Published
- 2026-02-05
- DOI
- https://doi.org/10.1126/science.aec6243
- Citations
- 1
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 52.10
Funders
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- China Postdoctoral Science Foundation
- Natural Science Foundation of Shandong Province
- National Science and Technology Major Project
- Natural Science Foundation of Anhui Province
- Fundamental Research Funds for the Central Universities