Analysis of the Classical Trajectory Treatment of Photon Dynamics for Polaritonic Phenomena

TL;DR

This paper evaluates the classical trajectory method for simulating photon dynamics in strong light-matter coupling, revealing that inaccuracies stem from inadequate light-matter correlation modeling rather than the classical treatment of photons.

Contribution

It introduces an analysis using the exact factorization approach to identify the source of errors in classical photon trajectory simulations.

Findings

Classical trajectory approach can underestimate photon numbers and intensities.

Inadequate light-matter correlation modeling causes simulation inaccuracies.

Errors become significant when photon numbers per mode exceed half.

Abstract

Simulating photon dynamics in strong light-matter coupling situations via classical trajectories is proving to be powerful and practical. Here we analyze the performance of the approach through the lens of the exact factorization approach. Since the exact factorization enables a rigorous definition of the potentials driving the photonic motion it allows us to identify that the cause of the underestimation of photon number and intensities observed in earlier work is primarily due to an inadequate accounting of light-matter correlation in the classical Ehrenfest force rather than errors from treating the photons quasiclassically per se. The latter becomes problematic when the number of photons per mode begins to exceed a half.