发表机构
Technical University of Munich; BMW Group; Munich Center for Quantum Science and Technology (MCQST)（慕尼黑工业大学; 宝马集团; 慕尼黑量子科学与技术中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出利用直接保真度估计测试概率误差消除中的参数误校准，并诊断参数高估或低估方向，同时通过纯度测量和双副本程序进一步确定误校准方向及与理想态的距离。
AI 中文摘要
概率误差消除（PEC）是量子计算中缓解噪声的标准技术，但其无偏性依赖于对底层噪声参数的准确了解。在实践中，这些参数是从实验数据中推断出来的，可能不准确。我们提出了一种协议，通过将直接保真度估计（DFE）应用于有效的缓解态，在硬件上测试PEC参数的一致性。所得的DFE重叠不仅作为参数误校准的见证，而且在适当条件下还揭示PEC参数是被高估还是被低估。我们在全局去极化噪声下对任意电路，以及在一般泡利随机噪声下对克利福德电路建立了这一行为。对于受泡利随机噪声影响的任意电路，低估结果普遍成立，而相应的高估结果则在额外的非简并条件下，对足够小的一致误校准以微扰方式建立。我们进一步表明，有效缓解算符的纯度提供了更一般的诊断，允许在任意电路和任意参数偏差下识别误校准方向。最后，我们描述了一种用于测量该量的双副本PEC程序，并表明它与DFE重叠一起，确定了与理想态的希尔伯特-施密特距离。我们协议产生的采样开销与PEC相同，并讨论了改进策略。
英文摘要
Probabilistic Error Cancellation (PEC) is a standard technique for mitigating noise in quantum computations, but its unbiasedness relies on accurate knowledge of the underlying noise parameters. In practice, these parameters are inferred from experimental data and may be inaccurate. We introduce a protocol that tests PEC parameter consistency on hardware by applying Direct Fidelity Estimation (DFE) to the effective mitigated state. The resulting DFE overlap serves not only as a witness of parameter miscalibration but, under appropriate conditions, also reveals whether the PEC parameters have been overestimated or underestimated. We establish this behavior for arbitrary circuits under global depolarizing noise and for Clifford circuits under general Pauli-stochastic noise. For arbitrary circuits subject to Pauli-stochastic noise, the underestimation result holds generally, while the corresponding overestimation result is established perturbatively for sufficiently small consistent miscalibrations under an additional nondegeneracy condition. We further show that the purity of the effective mitigated operator provides a more general diagnostic, allowing the miscalibration direction to be identified for arbitrary circuits and arbitrary parameter deviations. Finally, we describe a two-copy PEC procedure for measuring this quantity and show that, together with the DFE overlap, it determines the Hilbert-Schmidt distance from the ideal state. The sampling overhead incurred by our protocol is the same as that of PEC, and we discuss strategies to improve it.
Comments29 pages, 8 figures
