可重构${}^{171}$Yb原子阵列与可调谐电信波段纳米光纤腔的强耦合

中文摘要 AI 辅助

纳米光子腔在紧凑、直接光纤耦合的几何结构中提供强原子-光子耦合，而可重构的$^{171}$Yb原子阵列将高保真门操作与直接耦合到电信波段跃迁的亚稳态量子比特态相结合，使两者成为中性原子量子处理器与电信量子网络之间的天然接口。在此，我们在${}^{171}\mathrm{Yb}$的${}^{3}\mathrm{P}_0 \leftrightarrow {}^{3}\mathrm{D}_1$跃迁上实现了强原子-腔耦合，据我们所知，这是首个在电信波段原子跃迁上达到单原子强耦合区的中性原子腔量子电动力学（cavity-QED）系统。对单侧腔的反射光谱测量得到单原子内协同系数$C_{\mathrm{in}}=5.6(1.0)$，以及遵循$\sqrt{N}$标度、最高至$N=5$个原子的集体耦合，在沿纳米光纤约$200\\ \mathrm{\mu}$m的波腹处具有均匀耦合。光纤布拉格光栅的热调谐提供了对腔外耦合率的原位控制，可从欠耦合区到过耦合区跨越两个数量级，这与多种原子-腔协议相关。我们通过展示在距纳米光纤轴1 $\mathrm{\mu}$m处99.95(6)\\%的成像保真度和与自由空间阵列相当的陷阱寿命，确认了与可重构原子阵列的兼容性。此外，纳米光纤的直径工程化抗反射设计使得基于光镊的原子穿越纳米光纤的输运在纳米光纤上方4.5 $\mathrm{\mu}$m处无可测量损耗或加热，支持纳米光纤集成原子阵列的双层架构。基于所展示的原子-腔耦合、原子容量和腔模分布，我们预计时分复用的远程原子-原子纠缠生成速率可达40 kHz，并有望通过技术改进和信道复用进一步扩展。

英文摘要

Nanophotonic cavities provide strong atom-photon coupling in a compact, directly fiber-coupled geometry, while a reconfigurable array of $^{171}$Yb atoms combines high-fidelity gates with a metastable qubit state coupled directly to a telecom-band transition, making the two a natural interface between neutral-atom quantum processors and telecom quantum networks. Here, we realize strong atom-cavity coupling on the ${}^{3}\mathrm{P}_0 \leftrightarrow {}^{3}\mathrm{D}_1$ transition of ${}^{171}\mathrm{Yb}$, establishing, to our knowledge, the first neutral-atom cavity-QED system to reach the single-atom strong-coupling regime on a telecom-band atomic transition. Reflection spectroscopy of a single-sided cavity yields a single-atom internal cooperativity of $C_{\mathrm{in}}=5.6(1.0)$ and collective coupling following $\sqrt{N}$ scaling up to $N=5$ atoms, with homogeneous coupling at antinodes over $\sim$200 $\mathrmμ$m along the nanofiber. Thermal tuning of a fiber Bragg grating provides in situ control of the cavity outcoupling rate over two orders of magnitude from the undercoupled to the overcoupled regime, relevant for various atom-cavity protocols. We confirm compatibility with reconfigurable atom arrays by demonstrating 99.95(6)\% imaging fidelity and trap lifetimes comparable to free-space array, at 1 $\mathrmμ$m from the nanofiber axis. Moreover, the diameter-engineered antireflection design of the nanofiber enables tweezer-based atom transport across the nanofiber with no measurable loss or heating at 4.5 $\mathrmμ$m above the nanofiber, supporting a two-layer architecture for the nanofiber-integrated atom array. From the demonstrated atom-cavity coupling, atom capacity, and cavity mode profile, we project time-multiplexed remote atom-atom entanglement generation at 40 kHz, with prospects for further scaling through technical enhancements and channel multiplexing.

发表机构

• Nanofiber Quantum Technologies, Inc. (NanoQT)（纳米纤维量子技术有限公司）
• Department of Applied Physics, Waseda University（早稻田大学应用物理系）

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