Efficient evaluation of accuracy of molecular quantum dynamics using dephasing representation

TL;DR

This paper introduces a semiclassical dephasing representation method to efficiently evaluate the accuracy of lower-level quantum dynamics against higher-level calculations without performing full quantum simulations, demonstrated on CO2 photodissociation.

Contribution

The paper presents a novel, efficient semiclassical approach for assessing quantum dynamics accuracy without requiring quantum calculations, applicable to molecular simulations.

Findings

Feasibility demonstrated on CO2 photodissociation

Method can be integrated into existing molecular dynamics codes

Provides a quick accuracy assessment tool

Abstract

Ab initio methods for electronic structure of molecules have reached a satisfactory accuracy for calculation of static properties, but remain too expensive for quantum dynamical calculations. We propose an efficient semiclassical method for evaluating the accuracy of a lower level quantum dynamics, as compared to a higher level quantum dynamics, without having to perform any quantum dynamics. The method is based on dephasing representation of quantum fidelity and its feasibility is demonstrated on the photodissociation dynamics of CO2. We suggest how to implement the method in existing molecular dynamics codes and describe a simple test of its applicability.