Nonlinear level attraction of cavity axion polariton in antiferromagnetic topological insulator

TL;DR

This paper uncovers a novel nonlinear level attraction phenomenon in cavity axion polaritons within antiferromagnetic topological insulators, distinct from traditional mechanisms, with implications for quantum information and dark matter studies.

Contribution

It introduces a new nonlinear interaction mechanism causing gapless level attraction in cavity axion polaritons, different from linear coupling or dissipation effects.

Findings

Discovery of gapless level attraction in cavity axion polaritons

Identification of nonlinear interaction as the origin of level attraction

Potential applications in quantum information and dark matter detection

Abstract

Strong coupling between cavity photons and various excitations in condensed matters boosts the field of light-matter interaction and generates several exciting sub-fields, such as cavity optomechanics and cavity magnon polariton. Axion quasiparticles, emerging in topological insulators, were predicted to strongly couple with the light and generate the so-called axion polariton. Here, we demonstrate that there arises a gapless level attraction in cavity axion polariton of antiferromagnetic topological insulators, which originates from a nonlinear interaction between axion and the odd-order resonance of cavity. Such a novel level attraction is essentially different from conventional level attractions with the mechanism of either a linear coupling or a dissipation-mediated interaction, and also different from the level repulsion induced by the strong coupling in common polaritons. Our results reveal a new mechanism of level attractions, and open up new roads for exploring the axion polariton with cavity technologies. They have potential applications for quantum information and dark matter research.