U(1) slave-particle study of the finite-temperature doped Hubbard model in one and two dimensions

TL;DR

This paper develops a mean field theory for the doped Hubbard model in one and two dimensions, inspired by fractionalization in 1D systems, to analyze finite-temperature phase diagrams and spectral functions.

Contribution

It introduces a U(1) slave-particle mean field approach that captures fractionalized excitations in higher dimensions, extending concepts from 1D systems.

Findings

Identifies regions with higher spectral weight associated with fractionalized excitations.

Provides a finite-temperature phase diagram for the Hubbard chain and square lattice.

Derives spectral functions showing spin-charge separation signatures.

Abstract

One-dimensional systems have unusual properties such as fractionalization of degrees of freedom. Possible extensions to higher dimensional systems have been considered in the literature. In this work we construct a mean field theory of the Hubbard model taking into account a separation of the degrees of freedom inspired by the one-dimensional case and study the finite-temperature phase diagram for the Hubbard chain and square lattice. The mean field variables are defined along the links of the underlying lattice. We obtain the spectral function and identify the regions of higher spectral weight with the fractionalized fermionic (spin) and bosonic (charge) excitations.