Branch-Resolved Characterization of Feed-Forward Error in Dynamic Teleportation via Classical Choi Shadows
分支解析的动态传送中馈前误差特征化
Mason Edwards, Prabhat Mishra
AI总结 本文提出一种框架,用于在不丢失分支间行为信息的情况下表征动态电路传送中的馈前误差,通过实验重建纠缠参考量子比特的分支Choi算子,并验证了物理应用和后处理Choi阴影估计器,揭示了不同布局下误差结构和缓解行为的差异。
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中电路测量和经典馈前是超导量子处理器上动态电路传送的关键原始操作。然而,当按单独测量分支评估时,与测量条件的纠正操作相关的误差仍缺乏深入理解。本文提出一种框架,用于在不丢失其在不同分支间行为相关信息的情况下表征动态电路传送中的馈前误差。我们分析了三种应用测量条件纠正的方法:(i) 物理应用,(ii) 后处理调整,以及(iii) 一种利用基于位翻转平均(BFA)的概率读取误差缓解(PROM)的缓解物理应用。我们通过纠缠参考量子比特重建分支Choi算子,并验证了物理应用和后处理Choi阴影估计器与分支Choi算子全体谱学的对比。我们在两种物理量子比特布局上进行了实验,这两种布局在中电路测量读取误差上有显著差异,并观察到后处理和PROM缓解策略在分支质量上的相对顺序反转。在一种具有较高测量读取误差的布局中,操作馈前惩罚相对较低(约为0.02-0.03),并且PROM对每个分支产生比后处理更高的分支质量。在另一种具有较低读取误差的布局中,操作馈前惩罚增加到大约0.07,并且后处理在所有分支质量上超过PROM。我们的表征框架可以揭示分支特定的误差结构和缓解行为,这些行为是当前最先进的结果平均分析所无法揭示的。
Mid-circuit measurement and classical feed-forward are essential primitives for dynamic-circuit teleportation on superconducting quantum processors. However, the error associated with measurement-conditioned corrective operations remains poorly understood when evaluated with respect to individual measurement branches. In this paper, we present a framework for characterizing feed-forward error in dynamic circuit teleportation without losing valuable information related to its behavior across separate branches. We analyze three approaches to applying measurement-conditioned corrections: (i) physical application, (ii) post-processing adjustments, and (iii) a mitigated physical application which utilizes Bit-Flip Averaging (BFA)-based Probabilistic Readout Error Mitigation (PROM). We experimentally reconstruct branch Choi operators via an entangled reference qubit, and validate our physical-application and post-processing Choi-shadow estimators against full tomography of the branch Choi operators. We perform experiments on two physical qubit layouts which differ greatly in mid-circuit measurement readout error, and observe a reversal in the relative order in branch qualities obtained from the post-processing and PROM mitigation strategies. In one physical layout with higher measurement readout error, the operational feed-forward penalty is relatively modest (approximately 0.02-0.03) and PROM produces higher branch qualities than post-processing for every branch. In a separate layout with lower readout error, the operational feed-forward penalty increases to roughly 0.07, and post-processing exceeds PROM for all branch qualities. Our characterization framework can reveal branch-specific error structure and mitigation behavior that state-of-the-art outcome-averaged analyses fail to expose.