Deterministic multi-qubit entanglement in a quantum network
Deterministic multi-qubit entanglement in a quantum network
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DOI：
10.1038/s41586-021-03288-7
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发表时间：
2020-11
期刊：
影响因子：
64.8
通讯作者：
Y. Zhong;Hung-Shen Chang;A. Bienfait;É. Dumur;M. Chou;C. Conner;J. Grebel;R. Povey;Haoxiong Yan
中科院分区：
文献类型：
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作者：
Y. Zhong;Hung-Shen Chang;A. Bienfait;É. Dumur;M. Chou;C. Conner;J. Grebel;R. Povey;Haoxiong Yan
对于大规模量子通信和计算网络来说，高保真分布式多量子位纠缠的生成是一项具有挑战性的任务，，-。最近，两个远程量子位的确定性纠缠已通过光子、 、 、 、 - 和声子得到证明。然而，多量子位纠缠的确定性生成和传输尚未得到证明，这主要是由于状态转移保真度有限。在这里，我们报告了一个量子网络，包括两个通过一米长的超导同轴电缆连接的超导量子节点，其中每个节点包括三个互连的量子位。通过将电缆直接连接到每个节点中的一个量子位，我们可以以 0.911 ± 0.008 的过程保真度在节点之间传输量子态。我们还在一个节点中准备了一个三量子位 Greenberger-Horne-Zeilinger (GHZ) 状态，并确定性地将该状态转移到另一个节点，转移状态保真度为 0.656 ± 0.014。我们进一步使用该系统确定性地生成一个全局分布的两节点、六量子位 GHZ 状态，状态保真度为 0.722 ± 0.021。 GHZ 状态保真度明显高于真正多部分纠缠的 1/2 阈值，表明该架构可用于将多个超导量子处理器连贯地链接在一起，为构建大规模量子计算机提供模块化方法。
The generation of high-fidelity distributed multi-qubit entanglement is a challenging task for large-scale quantum communication and computational networks, , –. The deterministic entanglement of two remote qubits has recently been demonstrated with both photons, , , , –and phonons. However, the deterministic generation and transmission of multi-qubit entanglement has not been demonstrated, primarily owing to limited state-transfer fidelities. Here we report a quantum network comprising two superconducting quantum nodes connected by a one-metre-long superconducting coaxial cable, where each node includes three interconnected qubits. By directly connecting the cable to one qubit in each node, we transfer quantum states between the nodes with a process fidelity of 0.911 ± 0.008. We also prepare a three-qubit Greenberger–Horne–Zeilinger (GHZ) state, –in one node and deterministically transfer this state to the other node, with a transferred-state fidelity of 0.656 ± 0.014. We further use this system to deterministically generate a globally distributed two-node, six-qubit GHZ state with a state fidelity of 0.722 ± 0.021. The GHZ state fidelities are clearly above the threshold of 1/2 for genuine multipartite entanglement, showing that this architecture can be used to coherently link together multiple superconducting quantum processors, providing a modular approach for building large-scale quantum computers,.