标题： 一个千米级的光子链路连接两个稀释冰箱中的超导电路 显示英文标题

标题： A kilometer photonic link connecting superconducting circuits in two dilution refrigerators

摘要： 超导量子处理器是实现实用量子计算算法的主要平台。 尽管已经展示了具有数百个量子位的超导量子处理器，但其进一步扩展受到稀释冰箱的物理尺寸和冷却能力的限制。 通过构建量子网络将不同冰箱中的量子位连接起来，可以克服这一限制，这需要微波到光学转换器以实现长距离的低损耗信号传输。 尽管各种设计和演示已经实现了高效且低附加噪声的转换器，但尚未实现分离冰箱之间的相干光子链路。 在本工作中，我们实验上展示了由一对频率匹配的氮化铝电光转换器通过1公里电信光纤连接的两个分别置于不同稀释冰箱中的超导电路之间的相干信号传输。 每个节点的转换器达到>0.1%的效率，相比商用电光调制器，转换效率可提高80分贝，为完全量子化的链路铺平了道路。 本工作为通过光子链路互连的可扩展超导量子网络提供了关键的设计指南。 显示英文摘要

摘要： Superconducting quantum processors are a leading platform for implementing practical quantum computation algorithms. Although superconducting quantum processors with hundreds of qubits have been demonstrated, their further scaling up is constrained by the physical size and cooling power of dilution refrigerators. This constraint can be overcome by constructing a quantum network to interconnect qubits hosted in different refrigerators, which requires microwave-to-optical transducers to enable low-loss signal transmission over long distances. Despite that various designs and demonstrations have achieved high-efficiency and low-added-noise transducers, a coherent photonic link between separate refrigerators has not yet been realized. In this work, we experimentally demonstrate coherent signal transfer between two superconducting circuits housed in separate dilution refrigerators, enabled by a pair of frequency-matched aluminum nitride electro-optic transducers connected via a 1-km telecom optical fiber. With transducers at each node achieving >0.1% efficiency, an overall 80 dB improvement in transduction efficiency over commercial electro-optic modulators is attainable, paving the way towards a fully quantum-enabled link. This work provides critical design guidelines towards scalable superconducting quantum networks interconnected by photonic links.