Quantum Simulation of the Unknown: Observation of Pseudogap Physics in the Fermi - Hubbard Model at Ultralow Temperatures

What happens when quantum simulations become cold enough to surprise us? So far, quantum simulations have primarily served as impressive proof-of-principle demonstrations, realizing a wide range of many-body quantum phases. However, temperatures have remained too high to truly access uncharted regimes relevant to strongly correlated quantum materials.

In this talk, I will present a recent breakthrough in which we use an ultracold-atom realization of the Fermi - Hubbard model to explore pseudogap physics in the doped regime. By achieving a several-fold reduction in temperature, we enter a new regime and observe, unexpectedly, a pronounced peak in the compressibility near 1/8 doping. This feature appears to separate a conventional metallic phase from a pseudogap phase. Furthermore, we measure characteristic signatures of a pseudogap in the excitation spectrum and begin to observe the emergence of spin stripe correlations.

This work represents a key advance in quantum simulation: it demonstrates that we can now address central open questions in condensed matter physics using controlled experiments in regimes that lie at the frontier of classical numerical methods.

Speaker: Markus Greiner, Harvard University