Scalable spin squeezing in an optical lattice with dipolar finite-range XY interactions.

Quantum-enhanced metrology promises to significantly mitigate one of the fundamental limitations, quantum projection noise (QPN), in current metrological experiments. The past two decades have seen significant interest in the creation of scalable spin squeezing, which implies reduction of QPN. 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. Instead, most systems implement native finite-range interactions, such as the XXZ model that naturally arises from atomic dipole-dipole interactions. Here we demonstrate the existence of microwave clock transitions in the ground hyperfine manifold of ¹⁶⁷Er that exhibit XY interactions, due to erbium’s uniquely large nuclear magnetic moment. 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. This demonstration establishes a novel method for preparing a metrologically useful coherent spin-squeezed state in a variety of cold atom experimental platforms.