Spin Squeezing of Itinerant Dipoles in an Erbium Quantum Gas Microscope*

Long-range interactions promise new developments in the field of quantum enhanced sensing. The past two decades have seen significant interest in the creation of scalable spin squeezing and exploring squeezing generation with alternatives to the paradigmatic one-axis-twisting model. Here we experimentally demonstrate metrological squeezing using novel microwave clock transitions in the ground hyperfine manifold of 167Er that harbor appreciable XY interactions. Typically spin squeezing has been achieved with all-to-all interactions, which in the context of trapped atom experiments requires complex state and interaction engineering. Neutral atoms in a sufficiently tight-spacing lattice offer a different pathway to achieving spin-squeezing via the intrinsic magnetic dipole-dipole interaction. We find that by taking advantage of the hyperfine coupling between J and I every neutral atom can find a magnetically insensitive transition with appreciable dipolar exchange. These transitions enable coherent many body spin physics on the second timescale. Following recent theory work, we use one of these transitions to generate spin squeezing in a site-resolved optical lattice quantum simulator. Our lattice experiment enables tunneling allowing us to investigate the question of how itinerant particles impact spin-squeezing. This demonstration establishes a novel method for preparing a metrologically useful coherent spin-squeezed state in a variety of cold atom experimental platforms.