Simultaneous Operation of Clock and Gravimetry in a Wannier-Stark Optical Lattice Clock

The exquisite measurement precision of atomic clocks and matterwave interferometers independently offer exciting opportunities to probe fundamental physics and gravity. Here we present a trapped atom interferometer technique [1] implemented in a 87Sr Wannier-Stark Lattice clock. We perform clock spectroscopy at lattice depths less than ten photon recoils with the optical local oscillator detuned from the clock transition by +/- mg*a, where a is the lattice spacing, m the Sr mass, and g the gravity. This process prepares coherent superposition of both the internal clock states and the external Wannier-Stark states. Generally, this approach will lead to strong collisional shifts and decoherence due to s-wave collisions between atoms in distinct clock states on the same lattice site [2, 3]. To overcome this, we use an optical superlattice during state preparation to prepare atoms on strictly every other lattice site, eliminating this on-site collision channel. By leveraging simultaneous interrogation of clock and motional degrees of freedom, this technique enables simultaneous extraction of a clock signal and measurement of g.

 

[1] Balland et al., Phys. Rev. Lett. 133, 113403 (2024)

[2] Aeppli et al., Science Advances 8 (41), eadc9242 (2022).

[3] Kim et al., Phys. Rev. Lett. 135, 103601 (2025).