Measuring total density correlations in a Fermi-Hubbard gas via bilayer microscopy

Thomas HartkeBotond OregNingyuan JiaMartin Zwierlein

Phys. Rev. Lett. 125, 113601 (2020)

DOI:10.1103/PhysRevLett.125.113601

arXiv:2003.11669

A Band insulator with n=2 fermions per site, surrounded by a Mott insulator of n=1 atoms per site

 

We report on the single atom and single site-resolved detection of the total density in a cold atom realization of the 2D Fermi-Hubbard model. Fluorescence imaging of doublons is achieved by splitting each lattice site into a double well, thereby separating atom pairs. Full density readout yields a direct measurement of the equation of state, including direct thermometry via the fluctuation-dissipation theorem. Site-resolved density correlations reveal the Pauli hole at low filling, and strong doublon-hole correlations near half filling. These are shown to account for the difference between local and non-local density fluctuations in the Mott insulator. Our technique enables the study of atom-resolved charge transport in the Fermi-Hubbard model, the site-resolved observation of molecules, and the creation of bilayer Fermi-Hubbard systems.