Pauli Center Blackboard Seminar

Nonequilibrium Quantum Dynamics of Excitons in Photoactive Molecular Complexes

by Michael Thorwart

Seminar room 2 (DESY Hamburg)

Seminar room 2

DESY Hamburg

The first steps of photosynthesis consist of the capture of a solar photon by a biomolecular antenna complex and the formation of an exciton. This excitation energy is transfered along a biomolecular complex via dipolar Coulomb coupling until it reaches the reaction center where this energy triggers a complicated series of chemical reactions. Since the early days of quantum mechanics, this energy transfer process has been considered as an incoherent hopping described by a Fermi Golden Rule type rate constant ("Forster transfer"). Recent experiments have challenged this orthodox view and claimed the observation of long-lived quantum coherence over several hundreds of femtoseconds - despite the presence of a "hot, wet and dirty" bio-environment. I will discuss the approach to this nonequilibrium problem within the theory of open quantum systems and show that non-Markovian bath fluctuations induced by a polar solvent can enhance the quantum coherence properties in damped quantum systems.