Strong coupling of the cyclotron motion of surface electrons on liquid helium to a microwave cavity

TL;DR

This paper demonstrates strong coupling between surface electrons on liquid helium and a microwave cavity, showing Rabi splitting observable in reflection and photoresponse, explained by classical electrodynamics.

Contribution

It reveals that the observed strong coupling and Rabi splitting can be fully explained by classical physics, challenging the quantum interpretation.

Findings

Rabi splitting observed in cavity reflection spectrum

Rabi splitting observed in electron ac current

Classical model explains the strong coupling phenomena

Abstract

The strong coupling regime is observed in a system of two-dimensional electrons whose cyclotron motion is coupled to an electro-magnetic mode in a Fabry-Perot cavity resonator. The Rabi splitting of eigenfrequencies of coupled motion is observed both in the cavity reflection spectrum and ac current of electrons, the latter probed by measuring their bolometric photoresponse. Despite the fact that similar observations of the Rabi splitting in many-particle systems have been described as a quantum-mechanical effect, we show that the observed splitting can be explained completely by a model based on the classical electrodynamics.