发表机构
Faculty of Sciences, Universidad Autónoma del Estado de México（墨西哥州立自治大学理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文证明Bell-CHSH测量数据可同时用于非局域性见证和延迟量传感，通过CHSH关联推导Fisher信息下界，并阐明Bell违背与计量有用性为不同资源。
AI 中文摘要
利用偏振纠缠光子的Bell-CHSH测量通常用作非局域性见证。本文表明，相同的符合计数数据也能为光学延迟量传感提供定量的计量认证。对于编码在单个光子上的局部双折射相位，我们直接从实验可获取的CHSH关联推导出经典Fisher信息，并获得以测量关联和CHSH参数相位导数表示的下界。在无偏边际两量子比特体系中，标准CHSH分析仪设置被证明同时是Bell最优和Fisher最优的，在理想情况下饱和了延迟量估计的量子Fisher信息。我们进一步分析了可见度降低、相位噪声、分析仪失准和有限符合计数，并构建了无需量子态层析即可评估的保守下置信界。结果还阐明Bell违背和计量有用性是不同资源：非零Fisher信息可在CHSH违背阈值以下持续存在。因此，该协议使标准Bell测试数据集既能提供非局域性基准，又能为量子偏振测量提供统计控制的灵敏度认证。
英文摘要
Bell-CHSH measurements with polarization-entangled photons are commonly used as nonlocality witnesses. Here we show that the same coincidence data can also provide a quantitative metrological certificate for optical retardance sensing. For a local birefringent phase encoded on one photon, we derive the classical Fisher information directly from experimentally accessible CHSH correlators and obtain a lower bound expressed in terms of the measured correlations and the phase derivative of the CHSH parameter. In the unbiased-marginal two-qubit regime, the canonical CHSH analyzer settings are shown to be simultaneously Bell-optimal and Fisher-optimal, saturating the quantum Fisher information for retardance estimation in the ideal case. We further analyze reduced visibility, phase noise, analyzer misalignment, and finite coincidence counts, and construct conservative lower confidence bounds that can be evaluated without quantum-state tomography. The results also clarify that Bell violation and metrological usefulness are distinct resources: nonzero Fisher information can persist below the CHSH-violation threshold. The protocol therefore enables a standard Bell-test data set to provide both a nonlocality benchmark and a statistically controlled sensitivity certificate for quantum polarimetry.
