Quantum chaos approach in exciton energy transfer in a photosynthetic system

Abstract

Abstract Photosynthesis is the most important photon-induced process to fuel the activities of the organism. In the current work, we have investigated the exciton energy transfer in a photosynthetic complex connected to a thermal bath using the quantum chaos approach. The statistical distribution of the energy levels of the system investigates a quasi-degeneracy level distribution and, therefore, a stable system. The system is sensitive to the environmental effects, and the Hamiltonian parameters. Among the practical factors, we have studied the effect of temperature and solvent on the chlorosome system. At low temperatures, the Izrailev distribution is quasi-Poisson and the general behavior of the system approaches to a nearly localized state. Gradually, with increasing temperature, it corresponds to the Poisson state and shows an improvement in exciton transmission. In the presence of a solvent, at low solvent frequency, via the increasing the temperature, the system changes its behavior from the localized state to the transition state. But, by increasing the frequency, the system presents the opposite behavior: with increasing the temperature, the system becomes more localized. Accordingly, the most appropriate conditions for exciton energy transfer in the chlorosome system are low-frequency solvent and high-temperature. To compare the temperature effect on different parts of the photosynthetic system, we have studied the temperature effect on the FMO complex conductivity, which shows the increase in conductivity and exciton energy transfer with increasing the temperature. Modulation of transport properties in the system provides the potential application in the nanoscale biomaterial devices.