Quasi-Diabatic Propagation Scheme for Simulating Polariton Chemistry

TL;DR

This paper introduces a generalized quasi-diabatic propagation scheme for simulating non-adiabatic polariton dynamics in molecule-cavity systems, enabling accurate and flexible quantum simulations using various diabatic methods.

Contribution

The work extends the quasi-diabatic scheme to polariton systems, allowing the use of any diabatic quantum dynamics method with improved accuracy over traditional approaches.

Findings

Mapping approaches yield highly accurate population dynamics.

The method outperforms Ehrenfest and surface hopping approaches.

The scheme facilitates interfacing diabatic methods with ab initio polariton data.

Abstract

We generalize the quasi-diabatic (QD) propagation scheme to simulate the non-adiabatic polariton dynamics in molecule-cavity hybrid systems. The adiabatic-Fock states, which are the tensor product states of the adiabatic electronic states of the molecule and photon Fock states, are used as the locally well-defined diabatic states for the dynamics propagation. These locally well-defined diabatic states allow using any diabatic quantum dynamics methods for dynamics propagation, and the definition of these states will be updated at every nuclear time step. We use several recently developed non-adiabatic mapping approaches as the diabatic dynamics methods to simulate polariton quantum dynamics in a Shin-Metiu model coupled to an optical cavity. The results obtained from the mapping approaches provide very accurate population dynamics compared to the numerically exact method and outperform the widely used mixed quantum-classical approaches, such as the Ehrenfest dynamics and the fewest switches surface hopping approach. We envision that the generalized QD scheme developed in this work will provide a powerful tool to perform the non-adiabatic polariton simulations by allowing a direct interface between the diabatic dynamics methods and ab initio polariton information.