Theory of antibound states in partially filled narrow band systems

TL;DR

This paper develops a Gutzwiller-based theory for two-particle responses in the Hubbard model, accurately predicting antibound states relevant for spectroscopy and cold atoms with computational efficiency.

Contribution

It introduces a simple, reliable method for analyzing antibound states in high-density Hubbard systems, outperforming traditional approximations.

Findings

Excellent agreement with exact diagonalization results.

Reliable predictions at high densities where other methods fail.

Applicable to Auger spectroscopy and cold atom experiments.

Abstract

We present a theory of the dynamical two-particle response function in the Hubbard model based on the time-dependent Gutzwiller approximation. The results are in excellent agreement with exact diagonalization on small clusters and give reliable results even for high densities, where the usual ladder approximation breaks down. We apply the theory to the computation of antibound states relevant for Auger spectroscopy and cold atom physics. A special bonus of the theory is its computational simplicity.