Dynamical Axion Field in Topological Magnetic Insulators

TL;DR

This paper demonstrates that magnetic fluctuations in topological insulators can mimic axion particles, proposing experimental methods to detect this dynamical axion field and a new optical modulator device based on this phenomenon.

Contribution

It reveals that topological insulators' magnetic fluctuations behave like axions and introduces experimental setups and a device leveraging this effect.

Findings

Magnetic fluctuations couple to electromagnetic fields as axions.

Proposed experiments for detecting dynamical axion fields.

Designed an optical modulator based on axion-like coupling.

Abstract

Axions are very light, very weakly interacting particles postulated more than 30 years ago in the context of the Standard Model of particle physics. Their existence could explain the missing dark matter of the universe. However, despite intensive searches, they have yet to be detected. In this work, we show that magnetic fluctuations of topological insulators couple to the electromagnetic fields exactly like the axions, and propose several experiments to detect this dynamical axion field. In particular, we show that the axion coupling enables a nonlinear modulation of the electromagnetic field, leading to attenuated total reflection. We propose a novel optical modulators device based on this principle.