Distributed quantum sensing can provide quantum-enhanced sensitivity beyond the shot-noise limit (SNL) for sensing spatially distributed parameters. To date, distributed quantum sensing experiments have mostly been accomplished in laboratory environments without a real space separation for the sensors. In addition, the post-selection is normally assumed to demonstrate the sensitivity advantage over the SNL. Here, we demonstrate distributed quantum sensing with discrete variables in field and show the unconditional violation (without post-selection) of SNL up to 0.916 dB for the field distance of 240 m. The achievement is based on a loophole-free Bell test setup with entangled photon pairs at the averaged heralding efficiency of 73.88%. Moreover, to test quantum sensing in real life, we demonstrate the experiment for long distances (with 10-km fiber), together with the sensing of a completely random parameter. The results represent an important step towards a practical quantum sensing network for widespread applications.

中文翻译：

---

无后选择的分布式量子传感现场演示

分布式量子传感可以提供超出散粒噪声极限 (SNL) 的量子增强灵敏度，用于传感空间分布参数。迄今为止，分布式量子传感实验大多是在实验室环境中完成的，传感器没有真正的空间分离。此外，通常假设后选择展示了相对于 SNL 的灵敏度优势。在这里，我们展示了在场中具有离散变量的分布式量子传感，并在 240 m 的场距下显示了高达 0.916 dB 的 SNL 无条件违反（无后选择）。该成就基于具有纠缠光子对的无漏洞贝尔测试设置，平均预示效率为 73.88%。此外，为了在现实生活中测试量子传感，我们演示了长距离实验（使用 10 公里光纤），以及完全随机参数的感测。结果代表了朝着广泛应用的实用量子传感网络迈出的重要一步。