Ion trap-integrated optical cavities for fast networked quantum computation

量子计算的QCS愿景使用分布式模块处理器(联网的‘节点’)依赖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182赫兹的NQIT结果[物理。莱特牧师。124,110501(2020年)]；任何进一步的性能提高都将是温和和来之不易的，因为通过折射光学实现的光子收集效率有限。与此同时，一个有用的联网处理器将需要更高的远程纠缠率。最重要的是，它还需要更简单、更可靠的节点，其设计适合大规模制造，只需最少的维护和校准。长期以来，人们已经认识到，光学腔提供了一种优雅的光子收集途径，其效率接近单位。这提供了以MHz速率进行高保真远程纠缠操作的可能性，可与最快的局部两量子比特离子门相媲美。然而，将离子陷阱和空穴结合在一起的实验历来面临着一系列技术挑战。这些问题包括保持镜面对准的困难，以及由于介质镜表面的接近而引起的俘获电势的扰动

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