Exciton-phonon information flow in the energy transfer process of photosynthetic complexes

TL;DR

This paper investigates how non-Markovian and non-equilibrium phonon effects influence energy transfer in photosynthetic complexes, using advanced measures to analyze exciton-phonon information flow under realistic biological conditions.

Contribution

It introduces a new trace-distance measure for non-Markovianity and applies it within the hierarchical equation of motion framework to study photosynthetic energy transfer.

Findings

Non-Markovianity is significant in model dimer and Fenna-Matthews-Olson complex.

Exciton-phonon information flow is crucial for understanding energy transfer.

The proposed measure can be extended to other master equations.

Abstract

Non-Markovian and non-equilibrium phonon effects are believed to be key ingredients in the energy transfer in photosynthetic complexes, especially in complexes which exhibit a regime of intermediate exciton-phonon coupling. In this work, we utilize a recently-developed measure for non-Markovianity to elucidate the exciton-phonon dynamics in terms of the information flow between electronic and vibrational degrees of freedom. We study the measure in the hierarchical equation of motion approach which captures strong system-bath coupling effects and non-equilibrium molecular reorganization. We propose an additional trace-distance measure for the information flow that could be extended to other master equations. We find that for a model dimer system and the Fenna-Matthews-Olson complex that non-Markovianity is significant under physiological conditions.