Site-resolved measurement of the spin-correlation function in the Fermi-Hubbard model

TLDR

Strong correlations in quantum many‑body systems can give rise to exotic phases, and quantum gas microscopy enables unprecedented study of these correlations. We observe site‑resolved antiferromagnetic correlations in a two‑dimensional Hubbard‑regime optical lattice, measure spin correlations over arbitrary distances, extract thermodynamic quantities, detect significant correlations up to three sites, reach temperatures near numerical limits, and show that single‑particle‑level access deepens insight into the interplay of motion and magnetism.

Abstract

Exotic phases of matter can emerge from strong correlations in quantum many-body systems. Quantum gas microscopy affords the opportunity to study these correlations with unprecedented detail. Here, we report site-resolved observations of antiferromagnetic correlations in a two-dimensional, Hubbard-regime optical lattice and demonstrate the ability to measure the spin-correlation function over any distance. We measure the in situ distributions of the particle density and magnetic correlations, extract thermodynamic quantities from comparisons to theory, and observe statistically significant correlations over three lattice sites. The temperatures that we reach approach the limits of available numerical simulations. The direct access to many-body physics at the single-particle level demonstrated by our results will further our understanding of how the interplay of motion and magnetism gives rise to new states of matter.