Towards a cryogenic quantum gas microscope for low-temperature Fermi-Hubbard physics

The Fermi-Hubbard model is conjectured to capture some of the most exotic and important features of strongly correlated electrons in condensed matter systems. This

includes the intriguing case of cuprate materials, known for high-temperature superconductivity. However, despite its relative simplicity, exploring the Fermi-Hubbard system with analytical or numerical methods is notoriously difficult. As an alternative,, ultracold atoms trapped in optical lattices have been used as an analog simulator to study the Fermi-Hubbard Hamiltonian, allowing precise tuning of the system parameters and single-site-resolved measurements of charge and spin. Despite tremendous progress, there is still approximately a factor of five discrepancy between the state-of-the-art and the estimated temperature to observe the d-wave superconducting phase as well as potentially other intriguing phases. One key hypothesis of preventing experiments to reach colder systems is the heating due to holes stochastically generated deep in the Fermi sea, among other reasons, background gas collision due to imperfect vacuum could have a major contribution. Here we present the design of a cryogenic quantum gas microscope to reduce the hole generation rate, by cryopumping of the background gas; we further report on other design choices for improved Hubbard model temperatures.