Current advancements in technology have focused the attention of the quantum computing community toward exploring the potential of near-term devices whose computing power surpasses that of classical computers in practical applications. An unresolved central question revolves around whether the inherent noise in these devices can be overcome or whether any potential quantum advantage would be limited. There is no doubt that crosstalk is one of the main sources of noise in noisy intermediate-scale quantum (NISQ) systems, and it poses a fundamental challenge to hardware designs. Crosstalk between parallel instructions can corrupt quantum states and cause incorrect program execution. In this study, we present a necessary analysis of the crosstalk error effect on NISQ devices. Our approach is extremely straightforward and practical to estimate the crosstalk error of various multi-qubit devices. In particular, we combine the randomized benchmarking (RB) and simultaneous randomized benchmarking (SRB) protocol to estimate the crosstalk error from the correlation controlled-NOT (CNOT) gate. We demonstrate this protocol experimentally on 5-, 7-, \& 16-qubit devices. Our results demonstrate the crosstalk error model of three different IBM quantum devices over the experimental week and compare the error variation against the machine, number of qubits, quantum volume, processor, and topology. We then confirm the improvement in the circuit fidelity on different benchmarks by up to 3.06x via inserting an instruction barrier, as compared with an IBM quantum noisy device which offers near-optimal crosstalk mitigation in practice. Finally, we discuss the current system limitation, its tradeoff on fidelity and depth, noise beyond the NISQ system, and mitigation opportunities to ensure that the quantum operation can perform its quantum magic undisturbed.

翻译：当前的技术进步已将量子计算领域的关注点转向探索近期设备的潜力，这些设备的计算能力在实际应用中超越了经典计算机。一个尚未解决的核心问题围绕着这些设备固有的噪声能否被克服，或者任何潜在的量子优势是否会受到限制。毫无疑问，串扰是噪声中等规模量子（NISQ）系统中的主要噪声源之一，并对硬件设计构成了根本性挑战。并行指令间的串扰可能破坏量子态并导致程序错误执行。在本研究中，我们对串扰误差在NISQ设备上的影响进行了必要的分析。我们的方法极为简洁实用，可用于评估各种多量子比特设备的串扰误差。具体而言，我们结合随机基准测试（RB）和同步随机基准测试（SRB）协议，从受控非（CNOT）门的相关性中估计串扰误差。我们在5、7和16量子比特设备上对该协议进行了实验验证。我们的结果展示了三种不同IBM量子设备在一周实验周期内的串扰误差模型，并将误差变化与机器型号、量子比特数量、量子体积、处理器及拓扑结构进行了比较。随后，我们通过插入指令屏障，在不同基准测试中验证了电路保真度最高可提升3.06倍，相较于实际中提供近乎最优串扰缓解的IBM量子噪声设备。最后，我们讨论了当前系统的局限性、其在保真度与电路深度间的权衡、超越NISQ系统的噪声问题，以及确保量子操作能够不受干扰地展现其量子魔力的缓解机遇。