2026-02-06 中国科学院(CAS)
＜関連情報＞
- https://english.cas.cn/newsroom/cas_media/202602/t20260206_1149921.shtml
- https://www.science.org/doi/10.1126/science.aec6243
- https://www.nature.com/articles/s41586-026-10177-4
単一原子を用いた100 kmを超えるデバイス非依存の量子鍵配送 Device-independent quantum key distribution over 100 km with single atoms
Bo-Wei Lu, Chao-Wei Yang, Run-Qi Wang, Bo-Feng Gao, […] , and Jian-Wei Pan
Science Published:5 Feb 2026
DOI:https://doi.org/10.1126/science.aec6243
Editor’s summary
A robust and secure quantum internet will be reliant on device-independent quantum key distribution between parties over long distances. Such protocols have so far been limited to small-scale proof-of-principle demonstrations. Lu et al. used a pair of trapped single Rydberg atoms separated by up to 100 kilometers of optic fiber. Manipulating the state of the trapped atoms and using a single-photon interference protocol resulted in heralded entanglement between the two nodes and the ability to distribute quantum keys at metropolitan distances. This approach closes the gap between proof-of-principle quantum network experiments and real-world applications in quantum communication. —Ian S. Osborne
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.
スケーラブルな量子中継器のための長寿命遠隔イオン-イオンエンタングルメント Long-lived remote ion-ion entanglement for scalable quantum repeaters
Wen-Zhao Liu,Ya-Bin Zhou,Jiu-Peng Chen,Bin Wang,Ao Teng,Xiao-Wen Han,Guang-Cheng Liu,Zhi-Jiong Zhang,Yi Yang,Feng-Guang Liu,Chao-Hui Xue,Bo-Wen Yang,Jin Yang,Chao Zeng,Du-Ruo Pan,Ming-Yang Zheng,Xingjian Zhang,Shen Cao,Yi-Zheng Zhen,You Xiao,Hao Li,Lixing You,Xiongfeng Ma,Qi Zhao,… Jian-Wei Pan
Nature Published:02 February 2026
DOI:https://doi.org/10.1038/s41586-026-10177-4 An unedited version of this manuscript
Abstract
Quantum networks, integrating quantum communication, quantum metrology, and distributed quantum computing, could provide secure and efficient information transfer, high-resolution sensing, and an exponential speed-up in information processing1. Deterministic entanglement distribution over long distances is a prerequisite for scalable quantum networks2–5. However, the exponential photon loss in optical fibres prohibits efficient and deterministic entanglement distribution. Quantum repeaters6, incorporating entanglement swapping4,7,8 and entanglement purification9–11 with quantum memories, offer the most promising means to overcome this limitation in fibre-based quantum networks. Despite numerous pioneering efforts12–25, a critical bottleneck remains, as remote memory-memory entanglement suffers from decoherence more rapidly than it can be established and purified over long distances. Here, we demonstrate memory-memory entanglement between two nodes connected by 10 km of spooled fibre surviving beyond the average entanglement establishment time. This is enabled by the development of long-lived trapped-ion memories, an efficient telecom interface, and a high-visibility single-photon entanglement protocol26,27. As an application, we report a proof-of-principle device-independent quantum key distributio (DI-QKD) demonstration with finite-size analysis over 10 km and a positive key rate over 101 km in the asymptotic limit, with both distances exceeding previous work by more than two orders of magnitude28–30. Our work provides a critical building block for quantum repeaters and marks an important step toward scalable quantum networks.
