Satellites have shown free-space quantum-communication ability; however, they are orbit-limited from full-time all-location coverage. Meanwhile, practical quantum networks require satellite constellations, which are complicated and expensive, whereas the airborne mobile quantum communication may be a practical alternative to offering full-time all-location multi-weather coverage in a cost-effective way. Here, we demonstrate the first mobile entanglement distribution based on drones, realizing multi-weather operation including daytime and rainy nights, with a Clauser-Horne-Shimony-Holt S-parameter measured to be 2.41 ± 0.14 and 2.49 ± 0.06, respectively. Such a system shows unparalleled mobility, flexibility and reconfigurability compared to the existing satellite and fiber-based quantum communication, and reveals its potential to establish a multinode quantum network, with a scalable design using symmetrical lens diameter and single-mode-fiber coupling. All key technologies have been developed to pack quantum nodes into lightweight mobile platforms for local-area coverage, and arouse further technical improvements to establish wide-area quantum networks with high-altitude mobile communication.

中文翻译：

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基于无人机的移动量子网络纠缠分布

卫星已显示出自由空间量子通信能力；然而，它们在全时全位置覆盖范围内受到轨道限制。同时，实用的量子网络需要复杂且昂贵的卫星星座，而机载移动量子通信可能是一种以经济高效的方式提供全时全地点多天气覆盖的实用替代方案。在这里，我们展示了第一个基于无人机的移动纠缠分布，实现了包括白天和雨夜在内的多天气操作，测量的 Clauser-Horne-Shimony-Holt S 参数分别为 2.41 ± 0.14 和 2.49 ± 0.06。与现有的卫星和基于光纤的量子通信相比，这样的系统显示出无与伦比的移动性、灵活性和可重构性，并揭示了其建立多节点量子网络的潜力，该网络具有使用对称透镜直径和单模光纤耦合的可扩展设计。开发了所有关键技术，将量子节点打包成轻量级的移动平台进行局域覆盖，并激发进一步的技术改进，以建立具有高空移动通信的广域量子网络。