发表机构
University of California Berkeley; Washington University; Quantum Machines（加州大学伯克利分校; 华盛顿大学; 量子机器公司）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出贝叶斯自适应阈值化复位协议，利用完整测量历史动态调整反馈阈值，实现超导量子比特快速高保真复位，单比特保真度99.44%，五比特同时复位保真度98.78%，提供确定性复位时长。
AI 中文摘要
快速、高保真度的量子比特初始化是可扩展量子信息处理的关键基础操作，但传统的复位协议要么需要较长的弛豫时间，要么丢弃连续测量记录中包含的信息。我们展示了一种用于超导量子比特的自适应基于测量的复位协议，该协议使用贝叶斯推理在每次读出后更新量子比特状态估计，并动态调整反馈阈值。与固定阈值或重复直至成功（RUS）协议不同，该方法利用完整的模拟测量历史，使得复位决策随着基态制备置信度的增加而逐渐变得更加保守。通过基于FPGA的实时反馈在色散读出的transmon量子比特上实现，该协议在少量复位轮次后实现了$99.44\pm0.04\\%$的基态初始化保真度。我们进一步在多量子比特实验中比较了自适应复位与RUS策略，并表明自适应阈值化提供了确定性的复位持续时间，同时保持了$98.78 \pm 0.19\\%$的五量子比特同时复位保真度。这些结果确立了贝叶斯自适应阈值化作为超导量子处理器中快速量子比特复位的实用且可扩展的途径。
英文摘要
Fast, high-fidelity qubit initialization is a key primitive for scalable quantum information processing, but conventional reset protocols either require long relaxation times or discard information contained in continuous measurement records. We demonstrate an adaptive measurement-based reset protocol for superconducting qubits that uses Bayesian inference to update the qubit-state estimate after each readout and dynamically adjust the feedback threshold. Unlike fixed-threshold or repeat-until-success (RUS) protocols, the method utilizes the full analog measurement history, enabling the reset decision to become progressively more conservative as confidence in ground-state preparation increases. Implemented with real-time FPGA-based feedback on a dispersively readout transmon qubit, the protocol achieves a ground-state initialization fidelity of $99.44\pm0.04\%$ after a small number of reset rounds. We further compare adaptive reset with RUS strategies in multi-qubit experiments and show that adaptive thresholding provides deterministic reset duration while maintaining a five-qubit simultaneous-reset fidelity of $98.78 \pm 0.19\%$. These results establish Bayesian adaptive thresholding as a practical and scalable route to fast qubit reset in superconducting quantum processors.
Comments16 pages, 9 figures
