Equation of State of the Fermionic 2D Hubbard Model

TL;DR

This paper provides a numerically exact calculation of the equation of state for the 2D Hubbard model using large-cluster dynamical mean field theory, revealing temperature-dependent behaviors and implications for pseudogap physics.

Contribution

It offers the first controlled, finite-size scaled results for energy, entropy, and correlations in the 2D Hubbard model, relevant for cold atom experiments.

Findings

Identification of a strong behavioral shift in energy below temperature T*

Extrapolated thermodynamic quantities for large clusters

Reference data for doping levels away from half filling

Abstract

We present results for the equation of state of the two-dimensional Hubbard model on an isotropic square lattice as obtained from a controlled and numerically exact large-cluster dynamical mean field simulation. Our results are obtained for large but finite systems and are extrapolated to infinite system size using a known finite size scaling relation. We present the energy, entropy, double occupancy and nearest-neighbour spin correlations extrapolated to the thermodynamic limit and discuss the implications of these calculations on pseudogap physics of the 2D-Hubbard model away from half filling. We find a strong behavioural shift in energy below a temperature $T^*$ which becomes more pronounced for larger clusters. Finally, we provide reference calculations and tables for the equation of state for values of doping away from half filling which are of interest to cold atom experiments.