Transport through correlated quantum dots: An investigation using the functional renormalization group

TL;DR

This paper develops a systematic method to include higher order vertex functions in the functional renormalization group approach, revealing their importance in accurately describing transport in strongly correlated quantum dots.

Contribution

The paper introduces a method for systematically calculating higher order vertex functions in the fermionic functional renormalization group framework.

Findings

Higher order vertex functions are crucial for large Coulomb interactions.

Static approximation is inadequate for strong correlations.

The method improves the accuracy of transport property calculations.

Abstract

Calculations using the (exact) fermionic functional renormalization group are usually truncated at the second order of the corresponding hierarchy of coupled ordinary differential equations. We present a method for the systematic determination of higher order vertex functions. This method is applied to a study of transport properties of various correlated quantum dot systems. It is shown that for large Coulomb correlations higher order vertex functions cannot be neglected, and a static approximation is insufficient.