美国加州理工学院A. Faraon团队发现了多发射器量子网络节点的多重纠缠。相关论文于2025年2月26日发表在《自然》杂志上。

在远程节点之间分布纠缠的量子网络将解锁量子计算、通信和传感领域的转型技术。然而，最先进的网络每个节点只使用一个光学寻址的量子比特；这限制了量子通信带宽和内存资源，极大地阻碍了可扩展性。固态平台为多路复用量子网络提供了宝贵的资源，在这种网络中，多个光谱可区分的量子比特可置于纳米级体积中。

研究组通过实现一个由几个稀土离子耦合到纳米光子腔组成的双节点网络来利用这一资源。这是通过一种协议实现的，该协议通过频率擦除光子检测结合实时量子前馈来纠缠可区分的¹⁷¹Yb离子。这种方法对在比单次纠缠尝试更长的时间尺度上发生的缓慢光学频率波动具有鲁棒性：这是固态发射器面临的普遍挑战。研究组通过两种方式展示了这些多发射极节点的增强功能。

首先，通过两个远程离子对的多重纠缠来缓解纠缠分布率的瓶颈。其次，制备了由三个可区分离子组成的多部分W态，作为高级量子网络协议的资源。这些结果为基于稀土离子的可扩展量子网络奠定了基础。

附：英文原文

Title: Multiplexed entanglement of multi-emitter quantum network nodes

Author: Ruskuc, A., Wu, C.-J., Green, E., Hermans, S. L. N., Pajak, W., Choi, J., Faraon, A.

Issue&Volume: 2025-02-26

Abstract: Quantum networks that distribute entanglement among remote nodes will unlock transformational technologies in quantum computing, communication and sensing1,2,3,4. However, state-of-the-art networks5,6,7,8,9,10,11,12,13,14 use only a single optically addressed qubit per node; this constrains both the quantum communication bandwidth and memory resources, greatly impeding scalability. Solid-state platforms15,16,17,18,19,20,21,22,23,24 provide a valuable resource for multiplexed quantum networking in which multiple spectrally distinguishable qubits can be hosted in nano-scale volumes. Here we harness this resource by implementing a two-node network consisting of several rare-earth ions coupled to nanophotonic cavities25,26,27,28,29,30,31. This is accomplished with a protocol that entangles distinguishable 171Yb ions through frequency-erasing photon detection combined with real-time quantum feedforward. This method is robust to slow optical frequency fluctuations occurring on timescales longer than a single entanglement attempt: a universal challenge amongst solid-state emitters. We demonstrate the enhanced functionality of these multi-emitter nodes in two ways. First, we mitigate the bottlenecks to the entanglement distribution rate through multiplexed entanglement of two remote ion pairs32,33. Second, we prepare multipartite W-states comprising three distinguishable ions as a resource for advanced quantum networking protocols34,35. These results lay the groundwork for scalable quantum networking based on rare-earth ions.

DOI: 10.1038/s41586-024-08537-z

Source: https://www.nature.com/articles/s41586-024-08537-z