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MO: Fachverband Molekülphysik

MO 21: Electronic Spectroscopy I

MO 21.10: Talk

Thursday, March 17, 2011, 12:45–13:00, MER 02

Simulation of 2D-echo spectra of exitonic transfer in systems with large reorganisation energy on a GPU — •Birgit Hein¹, Christoph Kreisbeck¹, Tobias Kramer¹, and Mirta Rodriguez Pinilla² — ¹Institute for Theoretical Physics, University of Regensburg, Germany — ²Instituto de Estructura de la Materia, Madrid, Spain.

We analyse the Fenna-Matthews-Olson (FMO) complex of photosynthetic bacteria. Experimentally long lived quantum beatings have been observed at 77K (Engel, et al. (2007), Nature, 446, 782) and 294 K (Collini, et al. (2010). Nature, 463 644) which cannot be reproduced with a Markovian approach.

We calculate two dimensional echo spectra of the multi-site system, using an hierarchical propagation scheme suggested by Ishizaki and Fleming in 2009. This propagation scheme reproduces the long lived quantum beatings and works for systems with large coupling between excitonic and vibrational degrees of freedom. It also takes a back-action of the phonon-bath on the system into account. We tackle the computational demanding problem by implementing it on a graphic processing units (GPU) and using the enormous speed-up provided thus. This efficient implementation obliterates the need for approximative methods frequently used and facilitates the interpretation and comparison of theory and experiments for systems with large reorganisation energy.