Polaritonic Coupled-Cluster Theory

TL;DR

This paper introduces a coupled-cluster theory tailored for electrons strongly interacting with photons, enabling accurate modeling of polaritonic systems and bridging quantum chemistry with light-matter interactions.

Contribution

It presents a novel bosonic extension of coupled-cluster theory for fermion-boson systems, validated against exact results for molecular Hamiltonians in cavity environments.

Findings

Accurately reproduces Rabi splittings and multi-photon effects

Matches full configuration interaction results for ground-state properties

Provides a pathway for integrating into existing quantum chemistry software

Abstract

We develop coupled-cluster theory for systems of electrons strongly coupled to photons, providing a promising theoretical tool in polaritonic chemistry with a perspective of application to all types of fermion-boson coupled systems. We show benchmark results for model molecular Hamiltonians coupled to cavity photons. By comparing to full configuration interaction results for various ground-state properties and optical spectra, we demonstrate that our method captures all key features present in the exact reference, including Rabi splittings and multi-photon processes. Further, a path on how to incorporate our bosonic extension of coupled-cluster theory into existing quantum chemistry programs is given.