Special AMO Seminar

The behavior of the doped Hubbard model at low temperatures is a central problem in correlated electron physics, with relevance to cuprate superconductors. Despite extensive computational studies, many open questions remain on its low-temperature phase diagram, motivating its study through quantum simulation with ultracold fermionic atoms in optical lattices. Here, leveraging a recent several-fold reduction in experimental temperatures, we report the first direct experimental observation of the pseudogap metal in the Hubbard model. These measurements are enabled by a novel, efficient spectroscopic technique with which we resolve the opening of a partial gap, which we further correlate with a thermodynamic anomaly in the equation of state that emerges at low temperatures. Our results partially characterize the pseudogap regime and suggest a link between the pseudogap and charge order, which can be probed in future work. These results signal the arrival of quantum simulators in a regime that both challenges modern computational methods and is relevant to open questions on correlated materials.