Record Precision in a 1D Optical Lattice Clock

We report on the experimental progress of the JILA strontium 1D optical lattice clock. Our gravity-titled shallow lattice allows us to precisely control the interactions of the atoms and the resulting frequency shift. By analyzing the image of the atomic cloud, we account for various spatial inhomogeneities of the system including the atomic density. By tuning atomic interactions, we obtain ‘magic’ lattice depth where the density shift of the fractional frequency is canceled down to 5E-21 per atom [1]. Furthermore, we compare two regions of the cloud self synchronously, resolving the frequency gradient from the gravitational redshift across a 1 mm scale atomic ensemble [2]. These results bode well for a systematic accuracy evaluation at the 19th digit. Toward that end, we will present recent work on and progress towards measuring the lattice light shift and black body radiation shifts in our system. 

[1] Aeppli, Alexander, et al. "Hamiltonian engineering of spin-orbit coupled fermions in a Wannier-Stark optical lattice clock." arXiv preprint arXiv:2201.05909 (2022).

[2] Bothwell, Tobias, et al. "Resolving the gravitational redshift within a millimeter atomic sample." arXiv preprint arXiv:2109.12238 (2021); Nature, in press (2022).