Role of quantum coherence in chromophoric energy transport

TL;DR

This paper investigates how quantum coherence and environmental factors influence energy transfer in biological systems, introducing new analytical methods to quantify their contributions, with findings highlighting the significant roles of relaxation and coherence.

Contribution

It presents two novel approaches using Green's functions and susceptibilities to quantify physical process contributions to energy transfer efficiency.

Findings

Coherent dynamics contribute about 10% to energy transfer.

Relaxation processes account for approximately 80%.

New methods enable detailed analysis of energy transfer mechanisms.

Abstract

The role of quantum coherence and the environment in the dynamics of excitation energy transfer is not fully understood. In this work, we introduce the concept of dynamical contributions of various physical processes to the energy transfer efficiency. We develop two complementary approaches, based on a Green's function method and energy transfer susceptibilities, and quantify the importance of the Hamiltonian evolution, phonon-induced decoherence, and spatial relaxation pathways. We investigate the Fenna-Matthews-Olson protein complex, where we find a contribution of coherent dynamics of about 10% and of relaxation of 80%.