Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 17: Quantum Effects: Entanglement and Decoherence II
Q 17.3: Talk
Tuesday, March 24, 2015, 11:30–11:45, B/gHS
Extended quantum delocalization in photosynthetic complexes — •Christopher Schroeder1,3, Caycedo-Soler Felipe1, Autenrieth Caroline2, Ghosh Robin2, Huelga Susana1, and Plenio Martin1 — 1Institute for Theoretical Physics, Ulm University, Ulm, Germany — 2Department of Bioenergetics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany — 3Joint Quantum Institute, University of Maryland, College Park, USA
Light absorption in photosynthetic complexes occurs predominantly at light-harvesting (LH) antenna complexes, composed of many pigments, followed by excitation energy transfer (EET) between antenna complexes and the reaction centre (RC), containing far fewer pigments. Photon absorption is completed on timescales (~10fs) much shorter than both the coherence time (~100fs) and EET (~1-10ps), which means quantum mechanical delocalization across extended domains must be accounted for in an accurate description of the absorption process, regardless of the nature of transport. We develop a theory to characterize delocalization over extended domains in photosynthetic membranes of purple bacteria and show that the excitonic coupling among different units effects experimentally measurable redistributions of absorption intensity. Coupling between LH complexes leads to a polarized optical response which depends on the geometry of the array, the measurement of which would allow the experimental determination of the inter-complex Förster rate, and delocalization across LH1 and RC leads to an 80 % increase in RC absorption.