A Fermi-degenerate three-dimensional optical lattice clock

TLDR

Strontium optical lattice clocks can interrogate millions of atoms with a spectroscopic quality factor of 4 × 10⁻¹⁷, yet atomic interactions impose a trade‑off between stability and accuracy due to density‑dependent frequency shifts. The study demonstrates a scalable solution that uses the high, correlated density of a degenerate Fermi gas in a 3‑D optical lattice to suppress on‑site interaction shifts. The authors load a degenerate Fermi gas into a 3‑D lattice, leveraging its correlated density to mitigate interaction shifts. Contact interactions are resolved, reducing their contribution to clock shifts by orders of magnitude, and a synchronous comparison of two lattice regions achieves a 5 × 10⁻¹⁹ precision in one hour.

Abstract

Strontium optical lattice clocks have the potential to simultaneously interrogate millions of atoms with a high spectroscopic quality factor of $4 \times 10^{-17}$. Previously, atomic interactions have forced a compromise between clock stability, which benefits from a large atom number, and accuracy, which suffers from density-dependent frequency shifts. Here, we demonstrate a scalable solution which takes advantage of the high, correlated density of a degenerate Fermi gas in a three-dimensional optical lattice to guard against on-site interaction shifts. We show that contact interactions are resolved so that their contribution to clock shifts is orders of magnitude lower than in previous experiments. A synchronous clock comparison between two regions of the 3D lattice yields a $5 \times 10^{-19}$ measurement precision in 1 hour of averaging time.