Breakdown of the topological protection by cavity vacuum fields in the integer quantum Hall effect

TL;DR

This paper demonstrates that cavity vacuum fields can disrupt the topological protection in the integer quantum Hall effect by inducing long-range electron hopping, leading to finite resistivity.

Contribution

It reveals how vacuum electromagnetic fields in resonators can break topological protection in quantum Hall systems through cavity-mediated electron interactions.

Findings

Vacuum field fluctuations affect quantum Hall electron transport.

Breakdown of topological protection due to cavity-mediated electron hopping.

Vacuum fluctuations induce finite resistivity in the system.

Abstract

The control of the electronic properties of materials via the vacuum fields of cavity electromagnetic resonators is one of the emerging frontiers of condensed matter physics. We show here that the enhancement of vacuum field fluctuations in subwavelength split-ring resonators dramatically affects arguably one of the most paradigmatic quantum protectorates, namely the quantum Hall electron transport in high-mobility 2D electron gases. The observed breakdown of the topological protection of the integer quantum Hall effect is interpreted in terms of a long-range cavity-mediated electron hopping where the anti-resonant terms of the light-matter coupling finally result into a finite resistivity induced by the vacuum fluctuations. The present experimental platform can be used for any 2D material and provides new ways to manipulate electron phases in matter thanks to vacuum-field engineering