Explaining the observed long coherence effects by 2D photon echo experiments in photosynthetic EET : Two-Component Phonon Spectrum model

TL;DR

This paper introduces a Two-Component Phonon Spectrum model that explains long-lived quantum coherence observed in photosynthetic energy transfer experiments by combining polaron transformation and stochastic disorder.

Contribution

The paper presents a novel stochastic model that accounts for long coherence times in photosynthetic EET by integrating systematic and stochastic phonon components.

Findings

Successfully explains coherence up to 600 femtoseconds

Matches experimental 2D photon echo observations

Provides a unified framework for phonon effects in EET

Abstract

We propose a simple stochastic model which successfully explains the long coherence effects observed in photosynthetic Excitation Energy Transport (EET) by 2D photon echo experiments of G. S. Engel et. al. (Nature, {\bf 446} 782, (2007)). Our Two-Component Phonon Spectrum (TCPS) model is based upon the division of phonon degrees of freedom into a systematic component which is treated through polaron transformation and a stochastic component which is treated through dynamical disorder. This model successfully explains the observed long coherence upto $ \sim 600 fsec$ in EET experiments.