Gravity measurement at the sub-millimeter scale with optical lattice clock.

This article proposes a novel scheme for measuring gravity at the sub-millimeter scale using a vertical optical lattice clock (OLC) with periodic driving, leveraging Super-Bloch oscillations (SBOs) of atoms detected via the Rabi spectrum. The method, demonstrated under realistic experimental parameters for the ^87Sr OLC, achieves a sensitivity of 5 μGal/√Hz in the quantum projection noise limit, which is 50 times better than previous approaches based on amplitude modulation and CCD imaging in optical lattices. Key advantages include insensitivity to lattice laser noise—previously a major source of uncertainty—and the use of momentum-space observation through spectroscopy rather than real-space imaging. The authors detail the state preparation, evolution, and measurement processes, and optimize experimental parameters using Fisher information to maximize detection accuracy. This work suggests that OLC-based gravimetry can significantly advance precision gravity measurements at small spatial scales.