Departmental Colloquium: Prof. G. Engel (University of Chicago)
Quantum Mechanics in Biology: Imaging Coherent Energy Transfer in Photosynthesis
Excited states in the condensed phase have extremely high chemical potentials making them highly reactive and difficult to control. Yet in biology, excited state dynamics operate with exquisite precision driving solar light harvesting in photosynthetic complexes though excitonic transport. Apparently, these biological systems protect long-lived quantum coherence and display manifestly quantum mechanical behaviors. New data from two-dimensional electronic spectroscopy will be presented showing robustness of quantum coherence to perturbation, coupling between populations and coherences, separation of inhomogeneous and homogeneous dephasing processes, quantum coherence in the reaction center, and interference between relaxation pathways in LH2. The picture emerging from this data is one of robust and intrinsic control that is not sensitive to minor perturbations. These data indicate that a generalizable design principle may exist to enable synthetic devices to mimic the coherent energy transfer observed in photosynthetic systems.