Photonic quantum technology requires precise, time-resolved identification of photodetection events. In distributed quantum networks with spatially separated and drifting time references, achieving high precision is particularly challenging. Here we build on recent advances of using single-photons for time transfer and employ and quantify a fast postprocessing scheme designed to pulsed single-photon sources. We achieve an average root mean square synchronization jitter of 3.0 ps. The stability is comparable to systems with Rb vapor cell clocks with 19 ps at 1 s integration time, in terms of Allan time deviation. Remarkably, our stability is even better than classical high-precision time transfer, like the White Rabbit protocol, although we use significantly less signal (single-photon level). Our algorithms allow local processing of the data and do not affect the secure key rate. It compensates substantial clock imperfections from crystal oscillators and we foresee great potential for low signal scenarios. The findings are naturally suited to quantum communication networks and provide simultaneous time transfer without adding hardware or modifying the single-photon sources.

中文翻译：

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与脉冲单光子源的时钟同步


光子量子技术需要对光电探测事件进行精确的、时间分辨的识别。在具有空间分离和漂移时间参考的分布式量子网络中，实现高精度尤其具有挑战性。在这里，我们基于使用单光子进行时间传递的最新进展，并采用和量化了专为脉冲单光子源设计的快速后处理方案。我们实现了 3.0 ps 的平均均方根同步抖动。就艾伦时间偏差而言，其稳定性与具有 19 ps、1 s 积分时间的铷蒸汽电池时钟的系统相当。值得注意的是，我们的稳定性甚至比经典的高精度时间传输（如白兔协议）更好，尽管我们使用的信号明显较少（单光子水平）。我们的算法允许对数据进行本地处理，并且不会影响安全密钥速率。它补偿了晶体振荡器的大量时钟缺陷，我们预见到低信号场景的巨大潜力。这些发现自然适合量子通信网络，并且无需添加硬件或修改单光子源即可提供同步时间传输。