随机量子电路的计量基准测试
Metrological Benchmarking of Random Quantum Circuits
查看机构详情
- Korea Advanced Institute of Science and Technology（韩国科学技术院）
机构由 AI 辅助整理，请以论文原文为准。
浏览论文内容
中文总结 AI 辅助
提出基于量子Fisher信息的计量基准，通过受控扰动和蝴蝶协议表征随机量子电路，无需计算理想概率即可评估噪声实现，并区分Haar与Clifford系综。
中文摘要 AI 辅助
随机电路采样是展示量子计算优势的主要方法，但通过线性交叉熵对噪声实现进行基准测试需要计算理想输出概率，成本高昂。我们提出了一种基于受控扰动响应的计量基准，以量子Fisher信息（QFI）为特征。QFI与时间外序关联子之间的关系使得协议能够采用局部或全局控制。对于Haar随机电路，在局部协议下平均QFI接近其最大值，并在集体控制下随量子比特数线性增长。相比之下，Clifford电路尽管算子广泛传播，QFI却为零，这表明响应探测的是超越单纯传播的动力学性质。一种蝴蝶协议进一步利用系统尺寸增强灵敏度，在单量子比特读出下产生与量子比特数成正比的平均逆灵敏度。其涨落区分了Haar和Clifford系综，尽管它们的平均响应相同。对于噪声实现，我们在全局白噪声模型内推导了噪声QFI与理想QFI之间的精确关系，为基准的退化提供了定量参考。这些协议无需计算理想输出概率即可对噪声随机量子电路进行计量基准测试。
英文摘要
Random circuit sampling is a leading approach to demonstrating quantum computational advantage, but benchmarking noisy implementations through linear cross-entropy requires costly calculations of ideal output probabilities. We propose a metrological benchmark based on the response to controlled perturbations, characterized by quantum Fisher information (QFI). A relation between QFI and out-of-time-order correlators enables protocols with local or global control. For Haar-random circuits, the average QFI approaches its maximal value in the local protocol and grows linearly with the number of qubits under collective control. In contrast, Clifford circuits yield zero QFI despite extensive operator spreading, showing that the response probes dynamical properties beyond spreading alone. A butterfly protocol further uses system size to enhance sensitivity, yielding a mean inverse sensitivity proportional to the number of qubits with single-qubit readout. Its fluctuations distinguish the Haar and Clifford ensembles despite their identical mean responses. For noisy implementations, we derive an exact relation between the noisy and ideal QFI within a global white-noise model, providing a quantitative reference for the degradation of the benchmark. These protocols enable metrological benchmarking of noisy random quantum circuits without computing ideal output probabilities.
