A slave-boson mean-field theory for general multi-band Hubbard models

TL;DR

This paper presents a novel slave-boson mean-field approach for multi-band Hubbard models, enabling exact reformulation in an extended Hilbert space and naturally incorporating superconducting order, with results consistent with Gutzwiller theory.

Contribution

Introduces a new slave-boson mean-field method for multi-band Hubbard models that exactly reformulates the quantum problem and includes superconducting states.

Findings

Ground-state energy matches Gutzwiller theory results

Method naturally includes superconducting order

Applicable to general multi-band Hubbard models

Abstract

We introduce a new slave-boson mean-field theory which allows the investigation of general multi-band Hubbard models. Unlike earlier attempts of such a generalisation, in our approach the quantum-mechanical problem is exactly reformulated in an extended Hilbert space of Fermions and Bosons before a mean-field approximation is applied. Systems with superconducting order parameters are naturally included in our formalism. Our ground-state energy functional agrees with the corresponding quantity derived within the Gutzwiller theory.