Theoretical proposals to measure resonator-induced modifications of the electronic ground-state in doped quantum wells

TL;DR

This paper proposes theoretical methods to detect how strong light-matter coupling in quantum wells alters their electronic ground state, focusing on virtual excitations and their measurable effects with current technology.

Contribution

It introduces two novel measurement approaches to observe cavity-induced modifications of the electronic ground state in doped quantum wells.

Findings

Both proposed effects are observable with current or near-future technology.

The methods enable direct measurement of cavity-induced ground-state charge redistribution.

The work advances understanding of non-perturbative light-matter interactions in solid-state systems.

Abstract

Recent interest in the physics of non-perturbative light-matter coupling led to the development of solid-state cavity quantum electrodynamics setups in which the interaction energies are comparable with the bare ones. In such a regime the ground state of the coupled system becomes interaction-dependent and is predicted to contain a population of virtual excitations which, notwithstanding having been object of many investigations, remain still unobserved. In this paper we investigate how virtual electronic excitations in quantum wells modify the ground-state charge distribution, and propose two methods to measure such a cavity-induced perturbation. The first approach we consider is based on spectroscopic mapping of the electronic population at a specific location in the quantum well using localised defect states. The second approach exploits instead the photonic equivalent of a Kelvin probe to measure the average change distribution across the quantum well. We find both effects observable with present-day or near-future technology. Our results thus provide a route toward a demonstration of cavity-induced modulation of ground-state electronic properties.