AI 中文总结
本研究针对长离子链的运动加热问题，提出一种无需量子比特操作的双同位素协同冷却方案，可在室温下维持量子比特相干性，为降低长离子链门错误及模拟开放量子系统提供了关键支持。
AI 中文摘要
一维离子链因具备高可控性与高连通性，成为近期量子计算机极具吸引力的构建模块。然而，长离子链易受外部电场波动引发的运动加热影响。为实现深度计算，必须在不导致量子比特退相干或降低量子比特连通性的前提下抑制该噪声源。我们展示了对由量子比特（qubit）和冷却剂（coolant）离子组成的23离子链中所有与计算相关的运动模式进行稳态电路中段协同冷却的方案，且未使用任何量子比特操作。在室温系统中，我们的冷却方案使长波长轴向和径向模式的平均声子占据数保持在态制备后的数值附近，同时在长达56毫秒的电路期间，将用于实现纠缠门的模式维持在基态附近。至关重要的是，我们证明该冷却序列可保持量子比特相干性，并评估了其对单量子比特和两量子比特门操作的影响。此外，我们展示了一种利用不同种类间共享径向模式耦合的并行量子比特重置协议。我们的协同冷却方案是降低独立寻址长离子链中门错误的关键一步，并为开放量子系统模拟建立了通用平台。
英文摘要
Owing to their high controllability and connectivity, one-dimensional ion chains are attractive building blocks for near-term quantum computers. However, long ion chains are susceptible to motional heating caused by fluctuating external electric fields. To enable deep computations, this source of noise must be suppressed without inducing qubit decoherence or degrading qubit connectivity. We demonstrate steady-state mid-circuit sympathetic cooling of all computationally-relevant motional modes of a 23-ion chain consisting of \qubit qubit and \coolant coolant ions without using any qubit operations. In a room-temperature system, our cooling scheme preserves the mean phonon occupations of the long-wavelength axial and radial modes near their values following state preparation, while keeping the modes used to implement entangling gates near their ground states throughout a 56-ms circuit. Crucially, we show that our cooling sequence preserves qubit coherence, and evaluate its impact on single- and two-qubit gate operations. Additionally, we demonstrate a parallel qubit reset protocol leveraging the shared radial mode coupling between species. Our sympathetic cooling scheme represents a critical step toward reducing gate errors in individually-addressed long ion chains and establishes a versatile platform for simulating open quantum systems.
Comments33 pages, 36 figures
