We present a quantum sensing scheme achieving the ultimate quantum sensitivity in the estimation of the transverse displacement between two photons interfering at a balanced beam splitter, based on transverse-momentum sampling measurements at the output. This scheme can possibly lead to enhanced high-precision nanoscopic techniques, such as superresolved single-molecule localization microscopy with quantum dots, by circumventing the requirements in standard direct imaging of camera resolution at the diffraction limit, and of highly magnifying objectives. Interestingly, we show that our interferometric technique achieves the ultimate spatial precision in nature irrespectively of the overlap of the two displaced photonic wave packets, while its precision is only reduced of a constant factor for photons differing in any nonspatial degrees of freedom. This opens a new research paradigm based on the interface between spatially resolved quantum interference and quantum-enhanced spatial sensitivity.

中文翻译：

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通过双光子干涉采样测量以终极量子精度估计两个光子之间的横向位移

我们提出了一种量子传感方案，基于输出端的横向动量采样测量，在估计平衡分束器处干涉的两个光子之间的横向位移时实现了最终的量子灵敏度。该方案可能会带来增强的高精度纳米技术，例如采用量子点的超分辨率单分子定位显微镜，绕过衍射极限下相机分辨率的标准直接成像和高放大物镜的要求。有趣的是，我们表明，无论两个位移光子波包的重叠如何，我们的干涉技术实际上都能实现最终的空间精度，而对于任何非空间自由度不同的光子，其精度仅降低一个常数因子。这开辟了一种基于空间分辨量子干涉和量子增强空间灵敏度之间接口的新研究范式。