A coupled-trajectory quantum-classical approach to decoherence in non-adiabatic processes

TL;DR

This paper introduces a new quantum-classical method for simulating non-adiabatic dynamics that naturally incorporates electronic decoherence and nuclear wave packet splitting, improving upon Ehrenfest-like approaches.

Contribution

A novel coupled-trajectory quantum-classical approach derived from the exact factorization framework that accurately captures decoherence and wave packet splitting.

Findings

Method reproduces quantum decoherence effects

Captures nuclear wave packet splitting accurately

Shows improvement over Ehrenfest-like dynamics

Abstract

We present a novel quantum-classical approach to non-adiabatic dynamics, deduced from the coupled electronic and nuclear equations in the framework of the exact factorization of the electron-nuclear wave function. The method is based on the quasi-classical interpretation of the nuclear wave function, whose phase is related to the classical momentum and whose density is represented in terms of classical trajectories. In this approximation, electronic decoherence is naturally induced as effect of the coupling to the nuclei and correctly reproduces the expected quantum behaviour. Moreover, the splitting of the nuclear wave packet is captured as consequence of the correct approximation of the time-dependent potential of the theory. This new approach offers a clear improvement over Ehrenfest-like dynamics. The theoretical derivation presented in the Letter is supported by numerical results that are compared to quantum mechanical calculations.