Quantum Biology: Elucidating Design Principles From Photosynthesis

Kenley Pelzer, University of Chicago

Recent experiments suggest that quantum mechanical effects may play a role in the efficiency of photosynthetic light harvesting. However, much controversy exists about the interpretation of these experiments, in which light-harvesting complexes are excited by a femtosecond laser pulse. The coherence in such laser pulses raises the important question of whether these quantum mechanical effects are significant in biological systems excited by incoherent light from the sun. In our work, we apply frequency-domain Green’s function analysis to model a light-harvesting complex excited by incoherent light. By modeling incoherent excitation, we demonstrate that the evidence of long-lived quantum mechanical effects is not purely an artifact of peculiarities of the spectroscopy. This data provides a new perspective on the role of noisy biological environments in promoting or destroying quantum transport in photosynthesis.

Abstract Author(s): Kenley Pelzer, Tankut Can, Stephen Gray, Dirk Morr, and Greg Engel