Role of local duality invariance in axion electrodynamics of topological insulators

TL;DR

This paper develops a duality-invariant theory of topological insulators, linking it to axion electrodynamics, and predicts new effects related to dynamical axions and their influence on electromagnetic phenomena.

Contribution

It introduces a duality-invariant framework for topological insulators that connects to axion electrodynamics and predicts novel physical effects.

Findings

Reduction to axion electrodynamics in static case

Topological quantization linked to duality gauge potential multi-valuedness

Prediction of a new dual effect to dynamical axion fields

Abstract

Advances in material technology and confluence of ideas from particle physics, quantum field theory and condensed matter physics have led to the discovery of new states of matter as well as new physical phenomena: one of them termed as topological insulator has attracted a great deal of attention recently. Speculations on the possibility of observing the most elusive objects like axions and monopoles in topological insulators have led to studies that emphasize the role of symmetry and universality. In this paper we argue that electric-magnetic duality could be of deep significance in this context. We develop a duality invariant theory of topological insulators and show that under appropriate conditions this theory reduces to the axion electrodynamics for static case, topological quantization is related with the multi-valuedness of the duality gauge potential, and modifies Faraday's law for dynamical axion that would change the dispersion relation of axionic polariton. A new effect dual to the dynamical axion field effect is predicted and its physical consequences are discussed.