Theory of non-equilibrium transport in the SU(N) Kondo regime

TL;DR

This paper develops a Fermi liquid theory to analyze non-equilibrium transport and noise in SU(N) Kondo quantum dots, highlighting the importance of higher-order corrections and complex noise behavior in experimental conditions.

Contribution

It provides a comprehensive Fermi liquid framework for SU(N) Kondo systems, including higher-order effects and practical imperfections, especially for N=4 relevant to carbon nanotubes.

Findings

Higher-order Fermi liquid corrections are essential for accurate low-voltage predictions.

Noise behavior is complex due to interplay of shot noise and interaction effects.

Asymmetric couplings significantly influence transport and noise characteristics.

Abstract

Using a Fermi liquid approach, we provide a comprehensive treatment of the current and current noise through a quantum dot whose low-energy behaviour corresponds to an SU($N$) Kondo model, focusing on the case N=4 relevant to carbon nanotube dots. We show that for general $N$, one needs to consider the effects of higher-order Fermi liquid corrections even to describe low-voltage current and noise. We also show that the noise exhibits complex behaviour due to the interplay between coherent shot noise, and noise arising from interaction-induced scattering events. We treat various imperfections relevant to experiments, such as the effects of asymmetric dot-lead couplings.