# Engineering Quantum States of Matter for Atomic Clocks in Shallow Optical Lattices

## TL;DR

This paper analyzes how photon scattering in optical lattice clocks limits coherence times and proposes using shallow, state-independent lattices with larger lattice constants to approach the natural lifetime of the clock transition.

## Contribution

It introduces a novel approach of using shallow, state-independent optical lattices with larger lattice constants to reduce scattering and dephasing, enhancing atomic clock coherence times.

## Key findings

- Photon scattering limits coherence to less than 12 seconds.
- Shallow lattices can potentially extend coherence times to the natural lifetime.
- Proposed scheme is compatible with high-density Fermi gases.

## Abstract

We investigate the effects of stimulated scattering of optical lattice photons on atomic coherence times in a state-of-the art ${}^{87}\mathrm{Sr}$ optical lattice clock. Such scattering processes are found to limit the achievable coherence times to less than 12 s (corresponding to a quality factor of $1 \times 10^{16}$), significantly shorter than the predicted 145(40) s lifetime of ${}^{87}\mathrm{Sr}$'s excited clock state. We suggest that shallow, state-independent optical lattices with increased lattice constants can give rise to sufficiently small lattice photon scattering and motional dephasing rates as to enable coherence times on the order of the clock transition's natural lifetime. Not only should this scheme be compatible with the relatively high atomic density associated with Fermi-degenerate gases in three-dimensional optical lattices, but we anticipate that certain properties of various quantum states of matter can be used to suppress dephasing due to tunneling.