Liu Xiao, Hu Xiao-Min, Zhu Tian-Xiang, Zhang Chao, Xiao Yi-Xin, Miao Jia-Le, Ou Zhong-Wen, Li Pei-Yun, Liu Bi-Heng, Zhou Zong-Quan, Li Chuan-Feng, Guo Guang-Can
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, 230026, China.
CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, 230026, China.
Nat Commun. 2024 Oct 2;15(1):8529. doi: 10.1038/s41467-024-52912-3.
Quantum networks provide a prospective paradigm to connect separated quantum nodes, which relies on the distribution of long-distance entanglement and active feedforward control of qubits between remote nodes. Such approaches can be utilized to construct nonlocal quantum gates, forming building blocks for distributed quantum computing and other novel quantum applications. However, these gates have only been realized within single nodes or between nodes separated by a few tens of meters, limiting the ability to harness computing resources in large-scale quantum networks. Here, we demonstrate nonlocal photonic quantum gates between two nodes spatially separated by 7.0 km using stationary qubits based on multiplexed quantum memories, flying qubits at telecom wavelengths, and active feedforward control based on field-deployed fibers. Furthermore, we illustrate quantum parallelism by implementing the Deutsch-Jozsa algorithm and the quantum phase estimation algorithm between the two remote nodes. These results represent a proof-of-principle demonstration of quantum gates over metropolitan-scale distances and lay the foundation for the construction of large-scale distributed quantum networks relying on existing fiber channels.
量子网络提供了一种连接分离量子节点的前瞻性范式，它依赖于长距离纠缠的分布以及远程节点之间量子比特的主动前馈控制。这种方法可用于构建非局域量子门，形成分布式量子计算和其他新型量子应用的构建模块。然而，这些量子门仅在单个节点内或相隔几十米的节点之间实现，限制了在大规模量子网络中利用计算资源的能力。在此，我们利用基于复用量子存储器的静态量子比特、电信波长的飞行量子比特以及基于现场部署光纤的主动前馈控制，展示了在空间上相隔7.0公里的两个节点之间的非局域光子量子门。此外，我们通过在两个远程节点之间实现德伊奇-约扎算法和量子相位估计算法来说明量子并行性。这些结果代表了在城市规模距离上量子门的原理验证演示，并为依赖现有光纤通道构建大规模分布式量子网络奠定了基础。
