From integrability to conductance, impurity systems

TL;DR

This paper calculates the DC conductance of impurity systems using two integrability-based methods, demonstrating their agreement and providing insights into defect transport in fermionic models.

Contribution

It introduces a novel combination of thermodynamic Bethe ansatz and form factor expansion approaches to compute conductance in integrable impurity systems.

Findings

Excellent agreement between the two methods across various defect types

Validation of the Kubo formula approach for defect conductance

Enhanced understanding of impurity effects in fermionic transport

Abstract

We compute the DC conductance with two different methods, which both exploit the integrability of the theories under consideration. On one hand we determine the conductance through a defect by means of the thermodynamic Bethe ansatz and standard relativistic potential scattering theory based on a Landauer transport theory picture. On the other hand, we propose a Kubo formula for a defect system and evaluate the current-current two-point correlation function it involves with the help of a form factor expansion. For a variety of defects in a fermionic system we find excellent agreement between the two different theoretical descriptions.