Does nature use ‘quantum coherence’ to enhance efficiency?

The remarkable efficiency of energy transfer during the photosynthetic process, along with surprising experimental result that indicated the existence of quantum coherence in photosynthetic complexes, has raised two exciting questions: (i) Can quantum coherence exist in physiological conditions? (ii) Does nature use this coherence to improve photosynthetic efficiency? Recently, we have developed a theoretical methodology based on the theory of transport in open quantum systems, that enables us to provide a quantitative answer to these questions. Appling this methodology to two complexes - the PC-645 and the FMO complexes - we find that the answer is yes and no; while the energy transfer process is indeed in the quantum regime, quantum coherence has an insignificant contribution to the efficiency