Low-Temperature Behavior of the Large-U Hubbard Model from High-Temperature Expansions

TL;DR

This paper develops a new extrapolation method to analyze the low-temperature properties of the large-U Hubbard model using high-temperature series expansions, focusing on weakly interacting holes at low densities.

Contribution

A novel extrapolation technique for large-U Hubbard models that enables analysis down to near-zero temperature within specific parameter ranges.

Findings

Extrapolation valid for kT/t < 0.05 and hole densities below 0.2.

Implications for the magnetic phase diagram are discussed.

Method addresses convergence issues in high-temperature series expansions.

Abstract

We derive low-temperature properties of the large-U Hubbard model in two and three dimensions from exact series-expansion results for high temperatures. Convergence problems and limited available information prevent a direct or Pade'-type extrapolation. We propose a new method of extrapolation, which is restricted to large U and low hole densities, for which the problem can be mapped on that of a system of weakly interacting holes. In the new formulation an extrapolation down to T=0 can be obtained, but it can be trusted for the presently available series data for kT/t < 0.05 and for hole densities below 0.2 only. Implications for the magnetic phase diagram are discussed.