Optical conductivity for a dimer in the Dynamic Hubbard model

TL;DR

This paper analytically investigates the optical conductivity of a dimer in the Dynamic Hubbard model, revealing how pseudo-spin dynamics influence spectral weight distribution and confirming that holes are less mobile than electrons.

Contribution

It provides the first analytical results for spectral function and optical conductivity in a dimer within the Dynamic Hubbard model, highlighting polaron-like effects.

Findings

Holes are less mobile than electrons.

Spectral weight distribution is affected by pseudo-spin overlaps.

Analytical expressions match previous numerical results.

Abstract

The Dynamic Hubbard Model represents the physics of a multi-band Hubbard model by using a pseudo-spin degree of freedom to dynamically modify the on-site Coulomb interaction. Here we use a dimer system to obtain analytical results for this model. The spectral function and the optical conductivity are calculated analytically for any number of electrons, and the distribution of optical spectral weight is analyzed in great detail. The impact of polaron-like effects due to overlaps between pseudo-spin states on the optical spectral weight distribution is derived analytically. Our conclusions support results obtained previously with different models and techniques: holes are less mobile than electrons.