A resonance mechanism of efficient energy transfer mediated by Fenna-Matthews-Olson complex

The Wigner-Weisskopf-type model developed in [R. Alicki and F. Giraldi, J. Phys. B {\bf 44}, 154020 (2011)] is applied to the biological process of energy transfer from a large peripheral light harvesting antenna to the reaction center. This process is mediated by the Fenna-Matthews-Olson (FMO) photosynthetic complex with a remarkably high efficiency. The proposed model provides a simple resonance mechanism of this phenomenon employing exciton coherent motion and described by analytical formulas. A coupling to the vibrational environment is a necessary component of this mechanism as well as a fine tuning of the FMO complex Hamiltonian. The role of the relatively strong coupling to the energy sink in achieving the resonance condition and the absence of heating of the vibrational environment are emphasized.