Exact RG computation of the optical conductivity of graphene

TL;DR

This paper uses truncated exact Renormalization Group methods to compute the optical conductivity of interacting electrons in graphene, demonstrating a universal value with negligible low-frequency corrections.

Contribution

It provides a rigorous RG-based calculation of graphene's optical conductivity, confirming its universal value and analyzing low-frequency behavior.

Findings

Optical conductivity approaches pi/2 times the conductivity quantum.

Corrections to the universal value vanish as a power law at low frequencies.

The method confirms the universality of conductivity in interacting graphene.

Abstract

The optical conductivity of a system of electrons on the honeycomb lattice interacting through an electromagnetic field is computed by truncated exact Renormalization Group (RG) methods. We find that the conductivity has the universal value pi/2 times the conductivity quantum up to negligible corrections vanishing as a power law in the limit of low frequencies.