Environment-assisted quantum transport in photosynthetic complexes: Learning from nature for potential organic photovoltaic applications.

Saturday, November 1, 2008 - 5:30pm - 6:00pm
EE/CS 3-180
Alán Aspuru-Guzik (Harvard University)
Transport phenomena at the nanoscale are of interest due to the presence of
both quantum and classical behavior. In this work, we demonstrate that
quantum transport efficiency can be enhanced by a dynamical interplay of the
system Hamiltonian with the pure dephasing dynamics induced by a fluctuating
environment. This is in contrast to fully coherent hopping that leads to
localization in disordered systems, and to highly incoherent transfer that
is eventually suppressed by the quantum Zeno effect. We study these
phenomena in the Fenna-Matthews-Olson protein complex as a prototype for
larger photosynthetic energy transfer systems. We also show that disordered
binary tree structures exhibit enhanced transport in the presence of dephasing.
This phenomena could in principle be applied for the development of materials with
improved exciton transport properties. Our group is beginning work in this direction.
If time is available, I will describe our distributed computing effort for finding novel
candidates for organic photovoltaic devices by the harnessing volunteer CPU time.
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