一种用于25公里设备无关量子密钥分发的不对称原子-光子架构
An asymmetric atom-photon architecture for device-independent quantum key distribution over 25 km
- Universität des Saarlandes（萨尔兰州立大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究提出一种不对称原子-光子架构，在25公里光纤上实现设备无关量子密钥分发，通过双量子频率转换和主动偏振稳定获得|S|=2.75，超过阈值，产生69个密钥比特，为异构量子网络DIQKD铺路。
AI中文摘要：
设备无关量子密钥分发（DIQKD）可以在不信任测量设备内部工作的情况下保证安全性，但将其扩展到光纤网络需要同时具备高质量纠缠、可靠的预示和忠实的单光子传输。在此，我们在25公里盘绕电信光纤上实现了一种事件就绪的不对称原子-光子架构，以满足这些要求。单个囚禁的40Ca+离子构成协议的一方，而远程站测量的单个传输光子构成另一方。双量子频率转换和主动偏振稳定在整个链路上保持了原子-光子量子关联。我们获得的Clauser-Horne-Shimony-Holt参数为|S|=2.75^{+0.16}_{-0.15}，超过了所用DIQKD模型下正渐近密钥率所需的阈值|S|=2.362。在相同的渐近模型下，这对应于在10908个检测到的贝尔态中保守估计的69个秘密密钥比特。所展示的架构为异构、支持中继器的量子网络中的DIQKD建立了一条路径。
英文摘要：
Device-independent quantum key distribution (DIQKD) can guarantee security without trusting the internal workings of the measurement devices, but extending it to fiber networks demands high-quality entanglement, reliable heralding, and faithful photon transmission simultaneously. Here, we address these requirements in an event-ready asymmetric atom-photon architecture implemented over $25\,\mathrm{km}$ of spooled telecom fiber. A single trapped $^{40}\mathrm{Ca}^{+}$ ion forms one party of the protocol while a single transmitted photon measured at the remote station forms the other. Double quantum frequency conversion and active polarization stabilization preserve the atom-photon quantum correlation across the full link. We obtain a Clauser-Horne-Shimony-Holt parameter of $|S|=2.75^{+0.16}_{-0.15}$, exceeding the threshold $|S|=2.362$ required for a positive asymptotic secret-key fraction under the DIQKD model used. Within the same asymptotic model, this corresponds to a conservative estimate of 69 secret-key bits out of 10908 detected Bell states. The demonstrated architecture establishes a route towards DIQKD in heterogeneous, repeater-compatible quantum networks.
