A future quantum network will consist of quantum processors that are connected by quantum channels, just like conventional computers are wired up to form the Internet. In contrast to classical devices, however, the entanglement and nonlocal correlations available in a quantum-controlled system facilitate novel fundamental tests of quantum theory. In addition, they enable numerous applications in distributed quantum information processing, quantum communication, and precision measurement. While pioneering experiments have demonstrated the entanglement of two quantum nodes separated by up to 1.3 km, and three nodes in the same laboratory, accessing the full potential of quantum networks requires scaling of these prototypes to many more nodes and global distances. This is an outstanding challenge, posing high demands on qubit control fidelity, qubit coherence time, and coupling efficiency between stationary and flying qubits. This Colloquium describes how optical resonators facilitate quantum network nodes that achieve the aforementioned prerequisites in different physical systems (trapped atoms, defect centers in wide-band-gap semiconductors, and rare-earth dopants) by enabling high-fidelity qubit initialization and readout, efficient generation of qubit-photon and remote qubit-qubit entanglement, and quantum gates between stationary and flying qubits. These advances open a realistic perspective toward the implementation of global-scale quantum networks in the near future.

中文翻译：

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研讨会：腔增强量子网络节点

未来的量子网络将由通过量子通道连接的量子处理器组成，就像传统计算机连接起来形成互联网一样。然而，与经典设备相比，量子控制系统中可用的纠缠和非局域相关性促进了量子理论的新颖基础测试。此外，它们还支持分布式量子信息处理、量子通信和精密测量等领域的众多应用。虽然开创性的实验已经证明了两个相距 1.3 公里的量子节点以及同一实验室中的三个节点的纠缠，但要充分发挥量子网络的潜力，需要将这些原型扩展到更多的节点和全球距离。这是一项艰巨的挑战，对量子位控制保真度、量子位相干时间以及静止量子位和飞行量子位之间的耦合效率提出了很高的要求。本次研讨会描述了光学谐振器如何通过实现高保真量子位初始化和读出、高效地实现量子网络节点在不同物理系统（俘获原子、宽带隙半导体中的缺陷中心和稀土掺杂剂）中实现上述先决条件。量子位-光子和远程量子位-量子位纠缠的生成，以及静止量子位和飞行量子位之间的量子门。这些进展为在不久的将来实施全球规模的量子网络开辟了现实的前景。