Evidence for ideal insulating/conducting state in a 1D integrable system

TL;DR

This study investigates how integrability influences the conductive behavior of a 1D interacting fermion system, revealing that integrable models exhibit ideal insulating or conducting states depending on the regime, unlike non-integrable models.

Contribution

The paper demonstrates that integrable 1D systems can behave as perfect insulators or conductors at finite temperature, highlighting a fundamental difference from non-integrable systems.

Findings

Integrable systems act as ideal conductors in the metallic regime.

Integrable systems behave as ideal insulators in the insulating regime.

Non-integrable systems show typical metallic and activated insulating behavior.

Abstract

Using numerical diagonalization techniques we analyze the finite temperature/frequency conductance of a one dimensional model of interacting spinless fermions. Depending on the interaction, the observed finite temperature charge stiffness and low frequency conductance indicate a fundamental difference between integrable and non-integrable cases. The integrable systems behave as ideal conductors in the metallic regime and as ideal insulators in the insulating one. The non-integrable systems are, as expected, generic conductors in the metallic regime and activated ones in the insulating regime.