Quantum Many-Body Simulations of the Two-Dimensional Fermi-Hubbard Model in Ultracold Optical Lattices

Abstract

Understanding quantum many-body states of correlated electrons is one main theme in modern condensed-matter physics. We demonstrate the exponential tensor renormalization group (XTRG) algorithm [Chen et al., Phys. Rev. X 8, 031082 (2018)], complemented by independent determinant quantum Monte Carlo, offers a powerful combination of tools for studying the Fermi-Hubbard model. XTRG provides full and accurate access to the density matrix and thus various spin and charge correlations, down to an unprecedented low temperature of a few percent of the tunneling energy. We observe excellent agreement with ultracold fermion quantum simulations at both half filling and finite doping.