用压缩微波恢复超导量子比特磁力测量中受读出限制的Fisher信息

中文摘要 AI 辅助

超导量子比特磁力计的性能不仅取决于Ramsey询问期间磁场编码，还取决于编码信息在读出期间被恢复的效率。在此，我们量化了压缩微波辅助色散读出如何恢复在量子比特态分配期间丢失的磁场信息。我们开发了一个有效的检测模框架，将投影正交噪声、态分配误差和从二进制读出结果可获得的经典Fisher信息联系起来。压缩正交与判别轴之间的有限失配通过压缩和反压缩波动之间的竞争产生一个最优压缩强度。对于代表性参数，压缩读出将受读出限制的磁场灵敏度界降低了27.3%。这一改进源于恢复在读出阶段丢失的信息，而非增加Ramsey询问期间编码的信息。这些结果可能为减轻超导量子传感中测量阶段的信息损失提供一条实用途径。

英文摘要

The performance of superconducting-qubit magnetometers depends not only on magnetic-field encoding during Ramsey interrogation, but also on how efficiently the encoded information is recovered during readout. Squeezed microwaves provide a promising route to improve information extraction by suppressing readout noise, yet how such readout enhancement translates into accessible information for magnetic-field estimation remains unclear. Here we develop an effective detected-mode framework linking projected quadrature noise, state-assignment error, and the classical Fisher information accessible from binary readout outcomes. A finite mismatch between the squeezed quadrature and the discrimination axis produces an optimal squeezing strength through the competition between squeezed and anti-squeezed fluctuations. We further show that squeezed readout improves the readout-limited magnetic-field sensitivity by recovering information otherwise lost during state assignment, with the enhancement remaining robust against quadrature mismatch, transmission loss, and added noise. These results establish a quantitative connection between squeezed-microwave readout and measurement-stage information recovery in superconducting quantum sensing.

发表机构

• Institute of Quantum Materials and Physics, Henan Academy of Sciences（河南省科学院量子材料与物理研究所）
• Department of Physics, Central China Normal University（华中师范大学物理学院）
• State Key Laboratory of Mathematical Engineering and Advanced Computing（数学工程与先进计算国家重点实验室）
• Quantum Information Institute, School of Physics and Laboratory of Zhongyuan Light, Zhengzhou University（郑州大学物理学院量子信息研究所与中原之光实验室）

机构由 AI 辅助整理，请以论文原文为准。