Atoms and Molecules in Cavities: From Weak to Strong Coupling in QED Chemistry

TL;DR

This paper reviews how quantum chemistry concepts adapt when light-matter interactions in optical cavities range from weak to strong coupling, highlighting fundamental changes and introducing a new density-functional theory approach.

Contribution

It introduces a quantum-electrodynamical density-functional theory for modeling correlated electron-photon dynamics in cavity systems from first principles.

Findings

Fundamental changes in Born-Oppenheimer surfaces under strong coupling

Accurate description of single-photon emission dynamics

Development of a first-principles approach for matter-photon interactions

Abstract

In this work, we provide an overview of how well-established concepts in the fields of quantum chemistry and material sciences have to be adapted when the quantum nature of light becomes important in correlated matter-photon problems. Therefore, we analyze model systems in optical cavities, where the matter-photon interaction is considered from the weak- to the strong coupling limit and for individual photon modes as well as for the multi-mode case. We identify fundamental changes in Born-Oppenheimer surfaces, spectroscopic quantities, conical intersections and efficiency for quantum control. We conclude by applying our novel recently developed quantum-electrodynamical density-functional theory to single-photon emission and show how a straightforward approximation accurately describes the correlated electron-photon dynamics. This paves the road to describe matter-photon interactions from first-principles and addresses the emergence of new states of matter in chemistry and material science.