A major challenge in developing quantum computing technologies is to accomplish high precision tasks by utilizing multiplex optimization approaches, on both the physical system and algorithm levels. Loss functions assessing the overall performance of quantum circuits can provide the foundation for many optimization techniques. In this Letter, we use the quadratic error loss and the final-state fidelity loss to characterize quantum circuits. We find that the distribution of computation error is approximately Gaussian, which in turn justifies the quadratic error loss. It is shown that these loss functions can be efficiently evaluated in a scalable way by sampling from Clifford-dominated circuits. We demonstrate the results by numerically simulating 10-qubit noisy quantum circuits with various error models as well as executing 4-qubit circuits with up to ten layers of 2-qubit gates on a superconducting quantum processor. Our results pave the way toward the optimization-based quantum device and algorithm design in the intermediate-scale quantum regime.

中文翻译：

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使用Clifford采样的量子电路误差损失的可扩展评估

开发量子计算技术的主要挑战是在物理系统和算法级别上利用多重优化方法来完成高精度任务。评估量子电路整体性能的损失函数可以为许多优化技术提供基础。在这封信中，我们使用二次误差损失和最终状态保真度损失来表征量子电路。我们发现计算误差的分布近似为高斯分布，这反过来证明了二次误差的损失。结果表明，通过从Clifford支配的电路中进行采样，可以以可扩展的方式有效地评估这些损耗函数。我们通过对具有各种误差模型的10量子位噪声量子电路进行数值模拟，并在超导量子处理器上执行多达十层2量子位门的4量子位电路，来证明结果。我们的研究结果为在中等规模量子机制中基于优化的量子设备和算法设计铺平了道路。