Polaritonic coupled-cluster theory

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 multiphoton processes. Furthermore, a path on how to incorporate our bosonic extension of coupled-cluster theory into existing quantum chemistry programs is given.

A coupled cluster framework for electrons and phonons

“…In this work we describe a coupled cluster theory and corresponding EOM extension for interacting electrons and phonons. This theory is similar to some coupled cluster theories for cavity polaritons that have been independently developed over the last year 57,58 .…”

Role of Cavity Losses on Nonadiabatic Couplings and Dynamics in Polaritonic Chemistry

“…21 The molecular electronic and photonic degrees of freedom have been treated using model and/or semi-empirical Hamiltonians, 8,12,14,16,17 although there has been a recent surge in activity focused on merging ab initio molecular electronic structure theory with cavity quantum electrodynamics (ab initio CQED) to provide an accurate and predictive model of polaritonic structure. 13,[24][25][26][27][28][29] The dissipative nature of the photonic degrees of freedom has been less extensively explored in terms of how they impact upon the polaritonic structure itself, and on the dynamics that occur on one or more polaritonic surfaces. Here we couple a non-Hermitian CQED Hamiltonian 30 to a model Hamiltonian for the molecular electronic structure of azobenzene to simulate the polaritonic structure and dynamics with explicit inclusion of finite cavity lifetimes.…”

Thomas–Reiche–Kuhn (TRK) sum rule for interacting photons

“…The eigenstates of these systems, including the ground state, can display a complex structure involving superposition of several eigenstates of the noninteracting subsystems [22,23,59] and can be difficult to calculate. As a consequence, a number of approximation methods have been developed [60,61]. Moreover, the output field correlation functions, connected to measurements, depend on these eigenstates (see, e.g., [48,62]).…”