high performance computing on graphics processing units: hgpu.org

We study the energy transfer in light-harvesting complexes (LHC) and the importance of quantum coherence and the backaction of the molecular environment on the energy flow. We calculate the energy-transfer efficiency and the trapping time for the Fenna-Matthews-Olson (FMO) complex within the exact hierarchical approach proposed by Ishizaki and Fleming (J. Chem. Phys. vol 130, p. 234111, 2009), which accommodates the large reorganization energies and couplings between the excitonic degrees of freedom and the molecular environment typically found in LHCs. By using graphics processing units we offset the computational costs of the hierarchical approach and achieve a 448-fold performance speed-up, which allows us to consider large systems. We compare our exact results for the efficiency and trapping time as a function of some parameters of the model to other approximative methods commonly found in the literature.