Dynamical density correlation function of 1D Mott insulators in a magnetic field

TL;DR

This paper calculates the low-energy dynamical density-density correlation function of a 1D Mott insulator in a magnetic field, revealing singularities associated with exciton formation.

Contribution

It introduces a field theory approach to analyze the dynamical correlations in the extended Hubbard model under magnetic fields, highlighting exciton-related singularities.

Findings

Singularities in correlation function at specific energies and momenta

Exciton formation influences the dynamical response

Low-energy behavior characterized by field theory techniques

Abstract

We consider the one dimensional (1D) extended Hubbard model at half filling in the presence of a magnetic field. Using field theory techniques we calculate the dynamical density-density correlation function $\chi_{nn}(\omega,q)$ in the low-energy limit. When excitons are formed, a singularity appears in $\chi_{nn}(\omega,q)$ at a particular energy and momentum transfer.