Excitation spectra of a quantum ring embedded in a photon cavity

TL;DR

This paper investigates the dynamic energy exchange between electronic and photonic components in a quantum ring within a photon cavity, revealing the importance of both linear and quadratic interaction terms and analyzing oscillation spectra.

Contribution

It demonstrates the significance of including both linear and quadratic vector potential terms in modeling electron-photon interactions and analyzes the spectral differences in charge and photon number oscillations.

Findings

Energy oscillates between electronic and photonic parts.

Linear and quadratic terms have similar magnitude but opposite signs.

Distinct Fourier spectra for charge and photon oscillations.

Abstract

We explore the response of a quantum ring system coupled to a photon cavity with a single mode when excited by a classical dipole field. We find that the energy oscillates between the electronic and photonic components of the system. The contribution of the linear and the quadratic terms in the vector potential to the electron-photon interaction energy are of similar magnitude, but opposite signs stressing the importance of retaining both in the model. Furthermore, we find different Fourier spectra for the oscillations of the center of charge and the oscillations of the mean photon number in time. The Fourier spectra are compared to the spectrum of the many-body states and selection rules discussed. In case of the center of charge oscillations, the dipole matrix elements preselect the allowed Bohr frequencies of the transitions, while for the oscillations of the mean photon number, the difference of the photon content of the many-body states influences the selection rules.