AI 中文总结
该研究发现随机编译未破坏相干误差信息，其可通过保留的旋转标记恢复相干误差参数，在127量子比特IBM处理器上验证了标记估计器的高精度恢复效果。
AI 中文摘要
随机编译（RC）是将相干（系统性）门误差转化为随机噪声的标准技术。主流观点认为，该旋转操作会破坏相干误差信息。而精确的费舍尔信息守恒定律表明事实相反：RC从平均输出中移除的相干误差信息，完整保留在旋转标记中——即标准RC丢弃的逐次随机门选择。保留这些标记并构建标记-结果相关性，可在量子费舍尔信息极限下恢复相干误差参数，在所有标准非相干信道下无偏，且无额外电路成本。本文证明了两个定理，在12个电路族上以机器精度验证了守恒定律，并在127量子比特的IBM量子处理器（ibm_marrakesh）上确认了恢复效果。标记估计器在所有测试深度下，可将注入的相干相位恢复至真实值的0.0063弧度以内，而标准边际估计器在所有深度下均返回接近零的信号。
英文摘要
Randomized compiling converts a coherent gate error into a stochastic one by dressing each gate with a randomly chosen Pauli operator, and the standard view is that the coherent information is lost once outcomes are averaged over these random choices. This is incorrect: an exact Fisher-information identity shows that the averaged data and the correlation between the outcome and the random choice, the twirl label, together conserve the full information, and only the label is normally discarded. Retaining it turns an unmodified randomized-compiling run into an unbiased estimator for the coherent error, at no added circuit cost, valid under realistic decoherence and at any circuit depth. The same construction extends to coupling between qubits through two further mechanisms: a neighboring qubit prepared in a known, randomized state probes static coupling, and randomizing the pulse count used to prepare that state isolates a second, physically distinct leakage effect found unexpectedly on real hardware during this work. All three results are derived exactly, checked against closed-form oracles, and tested on a 127-qubit IBM processor. The single-qubit case is confirmed cleanly: an injected phase is recovered to 0.006~rad while the same data without labels shows no signal. The two-qubit extensions are validated at the level of the recovery circuit, with clean positive controls on hardware, though the coupling strengths themselves remain below the resolution of the shot budgets used here.
Comments8 pages, 3 figures, 3 tables
