都市网络中超过8000个模式的纠缠分发与量子存储
Entanglement distribution and quantum storage of more than 8000 modes over a metropolitan network
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中文总结 AI 辅助
该研究开发了含特定多模量子存储器的量子中继器节点，通过施密特分解定量测量时间模式容量，在都市光纤网络中实现了超8000个模式的纠缠分发与存储，为实用量子通信提供了支持。
中文摘要 AI 辅助
电信光子与物质之间的纠缠产生是基于光纤的量子中继器的核心，实现实用的通信速率需要复用，多模量子存储器可提供该功能。稀土离子系综可通过利用其吸收光谱内的大量光谱通道，实现大时间多模存储。本文报道了一个量子中继器节点，由$^{171}$Yb$^{3+}$:Y$_2$SiO$_5$多模量子存储器（具有250 MHz带宽和76.6 μs寿命）以及带宽匹配的纠缠光子对源组成。我们引入并通过施密特分解验证了有效时间模式容量的定量测量方法。利用该平台，我们展示了在25.3 km光纤卷中传播的电信光子与存储125 μs、对应16340个时间模式的979 nm光子之间的纠缠。最后，我们报告了现场部署结果：通过日内瓦都市光纤网络在5.66 km上分发纠缠，同时存储8235个模式，存储时长为63 μs。
英文摘要
Entanglement generation between telecommunication photons and matter is central to fibre-based quantum repeaters. Achieving practical communication rates requires multiplexing, which multimode quantum memories can provide. Rare-earth-ion ensembles offer large temporal multimode storage by exploiting the numerous spectral channels within their absorption spectrum. Here, we report on a quantum repeater node comprised of a $^{171}$Yb$^{3+}$:Y$_2$SiO$_5$ multimode quantum memory, featuring a 250 MHz bandwidth and a $76.6~μ\mathrm{s}$ lifetime, and a bandwidth-matched entangled photon-pair source. We introduce and validate a quantitative measure of the effective temporal mode capacity using a Schmidt decomposition. With this platform, we demonstrate entanglement between a telecom photon propagating through a 25.3 km fiber spool and a 979 nm photon stored for $125~μ\mathrm{s}$ across 16340 temporal modes. Finally, we report a field deployment distributing entanglement over 5.66 km through the Geneva metropolitan fibre network while storing 8235 modes for $63~μ\mathrm{s}$.
