Cavity correlated electron-nuclear dynamics from first principles

TL;DR

This paper develops a first-principles time-dependent density-functional theory to accurately model correlated electron, nuclear, and photon interactions in cavity quantum electrodynamics, enabling detailed predictions of light-matter phenomena.

Contribution

It introduces a unified theoretical framework combining electron, nuclear, and photon dynamics from first principles, with the first ab initio calculation of such a system.

Findings

Demonstrates one-to-one correspondence in quantum-electrodynamical density-functional theory

Calculates infrared spectra and quantum-electrodynamical observables for a CO₂ molecule in a cavity

Shows cavity-modulated molecular motion can alter chemical reaction pathways

Abstract

The rapidly developing and converging fields of polaritonic chemistry and quantum optics necessitate a unified approach to predict strongly-correlated light-matter interactions with atomic-scale resolution. Combining concepts from both fields presents an opportunity to create a predictive theoretical and computational approach to describe cavity correlated electron-nuclear dynamics from first principles. Towards this overarching goal, we introduce a general time-dependent density-functional theory to study correlated electron, nuclear and photon interactions on the same quantized footing. In our work we demonstrate the arising one-to-one correspondence in quantum-electrodynamical density-functional theory, introduce Kohn-Sham systems, and discuss possible routes for approximations to the emerging exchange-correlation potentials. We complement our theoretical formulation with the first ab initio calculation of a correlated electron-nuclear-photon system. From the time-dependent dipole moment of a CO$_2$ molecule in an optical cavity, we construct the infrared spectra and time-dependent quantum-electrodynamical observables such as the electric displacement field, Rabi splitting between the upper and lower polaritonic branches and cavity-modulated molecular motion. This cavity-modulated molecular motion has the potential to alter and open new chemical reaction pathways as well as create new hybrid states of light and matter. Our work opens an important new avenue in introducing ab initio methods to the nascent field of collective strong vibrational light-matter interactions.