标题： 在并行操作两个仅交换的量子比特 显示英文标题

标题： Operating two exchange-only qubits in parallel

摘要： 半导体是实现大规模量子计算机最具前景的平台之一，因为先进的制造技术允许制造大型量子点阵列。 可以在这些量子点阵列上使用各种量子比特编码来存储和操作量子信息。 无论采用哪种量子比特编码，精确控制阵列中受限于量子点的电子之间的交换相互作用都是关键。 此外，需要同时执行高保真度的量子操作，以充分利用单个量子比特的有限相干性。 在这里，我们展示了两个仅交换量子比特的并行操作，该量子比特由线性排列的六个量子点组成。 使用随机基准测试技术，我们表明在五个屏障门上发出脉冲以最大程度地并行调制交换相互作用，相对于顺序操作保持了量子比特控制的质量。 用于执行并行交换脉冲的技术可以轻松适应其他基于量子点的编码。 此外，我们展示了iSWAP门和电荷锁定泡利自旋阻塞读出方法的首次实验演示。 结果通过交叉熵基准测试进行验证，这是一种对更大规模量子计算系统性能进行表征的技术；在此首次应用于基于半导体技术的量子系统。 显示英文摘要

摘要： Semiconductors are among the most promising platforms to implement large-scale quantum computers, as advanced manufacturing techniques allow fabrication of large quantum dot arrays. Various qubit encodings can be used to store and manipulate quantum information on these quantum dot arrays. Regardless of qubit encoding, precise control over the exchange interaction between electrons confined in quantum dots in the array is critical. Furthermore, it is necessary to execute high-fidelity quantum operations concurrently to make full use of the limited coherence of individual qubits. Here, we demonstrate the parallel operation of two exchange-only qubits, consisting of six quantum dots in a linear arrangement. Using randomized benchmarking techniques, we show that issuing pulses on the five barrier gates to modulate exchange interactions in a maximally parallel way maintains the quality of qubit control relative to sequential operation. The techniques developed to perform parallel exchange pulses can be readily adapted to other quantum-dot based encodings. Moreover, we show the first experimental demonstrations of an iSWAP gate and of a charge-locking Pauli spin blockade readout method. The results are validated using cross-entropy benchmarking, a technique useful for performance characterization of larger quantum computing systems; here it is used for the first time on a quantum system based on semiconductor technology.