The time-dependent Gutzwiller theory for multi-band Hubbard models

TL;DR

This paper develops a multi-band extension of the time-dependent Gutzwiller theory to compute two-particle response functions, demonstrated through magnetic susceptibility in a two-band Hubbard model, highlighting differences from Hartree-Fock results.

Contribution

It introduces a novel multi-band time-dependent Gutzwiller approach for calculating response functions in complex correlated electron systems.

Findings

Significant differences between Gutzwiller and Hartree-Fock results for magnetic susceptibility.

Successful application to a two-band Hubbard model.

Enhanced understanding of two-particle responses in multi-band systems.

Abstract

We formulate a multi-band generalisation of the time-dependent Gutzwiller theory. This approach allows for the calculation of general two-particle response functions, which are crucial for an understanding of various experiments in solid-state physics. As a first application, we study the momentum- and frequency-resolved magnetic susceptibility in a two-band Hubbard model. Like in the underlying ground-state approaches we find significant differences between the results of our method and those from a time-dependent Hartree-Fock approximation.