Theory of single-particle properties of the Hubbard model

TL;DR

This paper presents an analytic method that accurately explains quantum Monte Carlo results for the Green's function in the 2D Hubbard model, revealing the disappearance of Fermi-liquid quasiparticles under certain magnetic conditions.

Contribution

It introduces a self-consistent analytic approach with vertex corrections that quantitatively matches numerical results for the Hubbard model.

Findings

Fermi-liquid quasiparticles vanish when antiferromagnetic correlations are strong.

The approach accurately reproduces quantum Monte Carlo Green's function data.

Antiferromagnetic correlation length influences quasiparticle behavior.

Abstract

It is shown that it is possible to quantitatively explain quantum Monte Carlo results for the Green's function of the two-dimensional Hubbard model in the weak to intermediate coupling regime. The analytic approach includes vertex corrections in a paramagnon-like self-energy. All parameters are determined self-consistently. This approach clearly shows that in two dimensions Fermi-liquid quasiparticles disappear in the paramagnetic state when the antiferromagnetic correlation length becomes larger than the electronic thermal de Broglie wavelength.