Interaction effects in Aharonov-Bohm-Kondo Rings

TL;DR

This paper investigates the conductance in an Aharonov-Bohm ring with a Kondo regime quantum dot, introducing a new method to analyze the effects of interactions and deriving explicit high-temperature conductance results.

Contribution

It develops a novel approach using basis transformation to screening and non-screening channels for analyzing conductance in Kondo systems.

Findings

Unusual conductance term involving 4-point Green's function identified.

Low-temperature conductance simplifies to a linear T-matrix expression.

Explicit high-temperature conductance results provided.

Abstract

We study the conductance through an Aharonov-Bohm ring, containing a quantum dot in the Kondo regime in one arm, at finite temperature and arbitrary electronic density. We develop a general method for this calculation based on changing basis to the screening and non-screening channels. We show that an unusual term appears in the conductance, involving the connected 4-point Green's function of the conduction electrons. However, this term and terms quadratic in the ${\rm T}$-matrix can be eliminated at sufficiently low temperatures, leading to an expression for the conductance linear in the Kondo T-matrix. Explicit results are given for temperatures high compared to the Kondo temperature.