Chemistry in Quantum Cavities: Exact Results, the Impact of Thermal Velocities and Modified Dissociation

TL;DR

This paper provides exact solutions for chemistry in optical cavities, examining the effects of thermal velocities and revealing new bound polaritonic states, thereby addressing fundamental questions and validating approximate models.

Contribution

It offers exact diagonalisation results of the Pauli-Fierz Hamiltonian, assessing the Jaynes-Cummings model's validity for electronic and ro-vibrational transitions, and explores thermal velocity effects.

Findings

Thermal velocities influence chemical properties without changing spectra.

Emergence of new bound polaritonic states beyond dissociation energy.

Validation of approximate models against exact diagonalisation results.

Abstract

In recent years tremendous progress in the field of light-matter interactions has unveiled that strong coupling to the modes of an optical cavity can alter chemistry even at room temperature. Despite these impressive advances, many fundamental questions of chemistry in cavities remain unanswered. This is also due to a lack of exact results that can be used to validate and benchmark approximate approaches. In this work we provide such reference calculations from exact diagonalisation of the Pauli-Fierz Hamiltonian in the long-wavelength limit with an effective cavity mode. This allows us to investigate the reliability of the ubiquitous Jaynes-Cummings model not only for electronic but also for the case of ro-vibrational transitions. We demonstrate how the commonly ignored thermal velocity of charged molecular systems can influence chemical properties, while leaving the spectra invariant. Furthermore, we show the emergence of new bound polaritonic states beyond the dissociation energy limit.