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

The prospect of controlling the electronic properties of materials via the vacuum fields of cavity electromagnetic resonators is emerging as one of the frontiers of condensed matter physics. We found that the enhancement of vacuum field fluctuations in subwavelength split-ring resonators strongly affects one of the most paradigmatic quantum protectorates, the quantum Hall electron transport in high-mobility two-dimensional 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 Hamiltonian develop into a finite resistivity induced by the vacuum fluctuations. Our experimental platform can be used for any two-dimensional material and provides a route to manipulate electron phases in matter by means of vacuum-field engineering.

Automated summary

Controlling electronic properties of materials through the vacuum fields of cavity electromagnetic resonators is a frontier in condensed matter physics. We found that enhanced vacuum field fluctuations in subwavelength split-ring resonators strongly affect quantum Hall electron transport. The breakdown of topological protection in the integer quantum Hall effect is attributed to long-range cavity-mediated electron hopping induced by vacuum fluctuations.