Intersubband Polaritons in the Electrical Dipole Gauge

TL;DR

This paper develops a theoretical framework using the electrical dipole gauge to describe intersubband polaritons in quantum heterostructures, capturing Coulomb interactions and collective plasmon modes for advanced solid-state QED studies.

Contribution

It introduces a comprehensive theoretical model in the electrical dipole gauge that automatically includes Coulomb interactions and describes collective plasmon modes in intersubband polariton systems.

Findings

The dipole gauge Hamiltonian naturally incorporates Coulomb interactions.

The model describes interactions between plasmon modes and light.

Framework applicable to ultra-strong light-matter coupling regimes.

Abstract

We provide a theoretical description for the coupling between the intersubband excitations of a bi-dimensional electron gas with the electromagnetic field. This description, based on the electrical dipole gauge, applies to an arbitrary quantum heterostructure embedded in a general multilayered waveguide or a microcavity. We show that the dipole gauge Hamiltonian automatically takes into account the Coulomb interactions in this system. Furthermore, it can be conveniently expressed in terms of the many-body collective plasmon modes, which interact both with each other and with the light field. The dipole gauge therefore provides a suitable framework for the study of solid state Quantum Electrodynamics (QED) phenomena, such as the ultra-strong light-matter interaction regime, occurring at very high electronic densities.