标题： 在城域网络中经过纠缠验证的时间分配 显示英文标题

标题： Entanglement-verified time distribution in a metropolitan network

摘要： 远程时钟的精确同步是广泛应用于许多领域的一项基本要求。 在这里，我们通过利用由量子点在电信波长下产生的纠缠和关联光子对，实验性地展示了一种新的量子时钟同步方法。 通过在斯德哥尔摩地区的城域光纤网络中分发这些纠缠光子，并测量远程关联，我们利用纠缠光子之间紧密的时间相关性实现了几十皮秒的同步精度。 我们通过执行远程量子态层析成像来验证纠缠光子的来源，从而证明我们的同步方案能够抵御伪装攻击。 我们测得的最大分布式纠缠保真度为$0.817 \pm 0.040$，接近于$|\Phi^+\rangle$的贝尔态，纠缠度为$0.660 \pm 0.086$。 这些结果突显了由量子点生成的纠缠对作为共享资源，在现实世界量子网络中用于安全时间同步和量子密钥分发的潜力。 显示英文摘要

摘要： The precise synchronization of distant clocks is a fundamental requirement for a wide range of applications. Here, we experimentally demonstrate a novel approach of quantum clock synchronization utilizing entangled and correlated photon pairs generated by a quantum dot at telecom wavelength. By distributing these entangled photons through a metropolitan fiber network in the Stockholm area and measuring the remote correlations, we achieve a synchronization accuracy of tens of picoseconds by leveraging the tight time correlation between the entangled photons. We show that our synchronization scheme is secure against spoofing attacks by performing a remote quantum state tomography to verify the origin of the entangled photons. We measured a distributed maximum entanglement fidelity of $0.817 \pm 0.040$ to the $|\Phi^+\rangle$ Bell state and a concurrence of $0.660 \pm 0.086$. These results highlight the potential of quantum dot-generated entangled pairs as a shared resource for secure time synchronization and quantum key distribution in real-world quantum networks.