Ion trap-integrated optical cavities for fast networked quantum computation

QCS使用分布式模块化处理器（联网的“节点”）进行量子计算的愿景取决于节点之间远程纠缠的快速产生。目前最先进的速率是我们的NQIT结果182 Hz [Phys. Rev. Lett. 124，110501（2020）];由于通过折射光学器件可实现的有限的光子收集效率，任何进一步的性能提高都将是适度的和来之不易的。同时，一个有用的网络处理器将需要更高的远程纠缠率。重要的是，它还需要更简单、更可靠的节点，设计适合大规模制造，需要最少的维护和校准。长期以来，人们一直认为，光学腔提供了一种接近单位效率的光子收集途径。这提供了以MHz速率进行高保真远程纠缠操作的可能性，可与最快的本地双量子位离子门相媲美。然而，结合离子阱和空腔的实验在历史上一直面临着一系列技术挑战。这些问题包括从保持镜对准的困难到由于介质镜表面的接近而引起的捕获电势的扰动

The QCS vision of quantum computing using distributed modular processors (networked 'nodes') depends upon the rapid production of remote entanglement between nodes. The current state-of-the-art rate is our NQIT result of 182 Hz [Phys. Rev. Lett. 124, 110501 (2020)]; any further performance increases will be modest and hard-won, due to the limited photon collection efficiency achievable via refractive optics. Meanwhile, a useful networked processor will require much higher remote entanglement rates. Critically, it will also need simpler and more reliable nodes, with a design amenable to large-scale fabrication and requiring minimal maintenance and calibration.It has long been recognised that optical cavities provide an elegant route to photon collection with near-unit efficiency. This presents the possibility of high-fidelity remote entangling operations at MHz rates, comparable to that of the fastest local two-qubit ion gates. However, experiments combining ion traps and cavities have historically struggled with a series of technical challenges. These have ranged from the difficulty of maintaining mirror alignment, to perturbations of the trapping potential due to the proximity of the dielectric mirror surfaces