近日，英国牛津大学的D. Main及其研究团队取得一项新进展。经过不懈努力，他们实现跨光学网络链路的分布式量子计算。相关研究成果已于2025年2月5日在国际权威学术期刊《自然》上发表。

该研究团队实验演示了两个通过光子互连的离子阱模块之间的量子计算分布。这两个模块相距约两米，每个模块都包含专用的网络量子比特和电路量子比特。通过利用网络量子比特之间的预告式远程纠缠，研究人员在两个模块中的电路量子比特之间确定性地隐形传态了一个受控Z（CZ）门，实现了86%的保真度。

随后，研究人员执行了格罗弗搜索算法——据他们所知，这是首个包含多个非局部两量子比特门的分布式量子算法实现——并测得71%的成功率。此外，研究人员还实现了分布式iSWAP和SWAP电路，分别编译了两个和三个量子门隐形传态实例，展示了分布任意两量子比特操纵的能力。由于光子可以与多种系统接口，因此此处演示的通用分布式量子计算架构为一系列物理平台实现大规模量子计算提供了一条可行途径。

据悉，分布式量子计算（DQC）将多个网络连接的量子处理模块的计算能力结合起来，理想情况下能够在不牺牲性能或量子比特连接性的前提下，执行大型量子电路。光子网络作为DQC的互连层，具有高度的灵活性和可重构性；网络中物质量子比特之间共享的远程纠缠，通过量子门隐形传态（QGT）实现了全连接逻辑网络。对于可扩展的DQC架构而言，QGT的实现必须是确定性的且可重复的；迄今为止，尚未有演示满足这些要求。

附：英文原文

Title: Distributed quantum computing across an optical network link

Author: Main, D., Drmota, P., Nadlinger, D. P., Ainley, E. M., Agrawal, A., Nichol, B. C., Srinivas, R., Araneda, G., Lucas, D. M.

Issue&Volume: 2025-02-05

Abstract: Distributed quantum computing (DQC) combines the computing power of multiple networked quantum processing modules, ideally enabling the execution of large quantum circuits without compromising performance or qubit connectivity. Photonic networks are well suited as a versatile and reconfigurable interconnect layer for DQC; remote entanglement shared between matter qubits across the network enables all-to-all logical connectivity through quantum gate teleportation (QGT). For a scalable DQC architecture, the QGT implementation must be deterministic and repeatable; until now, no demonstration has satisfied these requirements. Here we experimentally demonstrate the distribution of quantum computations between two photonically interconnected trapped-ion modules. The modules, separated by about twometres, each contain dedicated network and circuit qubits. By using heralded remote entanglement between the network qubits, we deterministically teleport a controlled-Z (CZ) gate between two circuit qubits in separate modules, achieving 86% fidelity. We then execute Grover’s search algorithm—to our knowledge, the first implementation of a distributed quantum algorithm comprising several non-local two-qubit gates—and measure a 71% success rate. Furthermore, we implement distributed iSWAP and SWAP circuits, compiled with two and three instances of QGT, respectively, demonstrating the ability to distribute arbitrary two-qubit operations. As photons can be interfaced with a variety of systems, the versatile DQC architecture demonstrated here provides a viable pathway towards large-scale quantum computing for a range of physical platforms.

DOI: 10.1038/s41586-024-08404-x

Source: https://www.nature.com/articles/s41586-024-08404-x