Complete Pseudoparticle Representation and the Conductivity Spectrum of the Hubbard Chain

TL;DR

This paper employs a complete pseudoparticle operator approach to analyze the finite-frequency conductivity spectrum of the Hubbard chain, revealing spectral weight distribution and exact absorption edge behaviors.

Contribution

It introduces a complete pseudoparticle representation to derive the explicit form of the conductivity spectrum in the Hubbard chain, including exact absorption edge dependencies.

Findings

Spectral weight mainly at  Drude peak (except at half-filling)

Exact ependence of absorption edges below twice the chemical potential

Absorption edge weights diminish with increasing on-site interaction U

Abstract

We use a complete pseudoparticle operator representation to study the explicit form of the finite-frequency conductivity for the Hubbard chain. Our study reveals that the spectral weight is mostly concentrated at the \omega =0 Drude peak (except at density n=1) and at an absorption starting just below twice the value of the chemical potential whose \omega-dependence we evaluate exactly. We also obtain the exact \omega dependence of the higher-energy, less-pronounced absorption edges, whose weights vanish for large on-site interaction U.