Explaining the observed long coherence effects by 2D photon echo   experiments in photosynthetic EET : Two-Component Phonon Spectrum model
  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. 
Navinder Singh, V. M. Kenkre, and R. E. Amritkar
physics.chem-ph cond-mat.stat-mech quant-ph