# Multiscale Multiexciton Cyclic Dynamics in Light Harvesting Complex

## TL;DR

This paper develops a comprehensive quantum-mechanical model for light harvesting complexes that accounts for multi-exciton states and various dynamic processes, providing a more complete understanding of energy transfer.

## Contribution

It introduces Lindblad-type Master equations derived from the many-body Schrödinger equation to describe cyclic exciton-electron dynamics beyond single-exciton approximation.

## Key findings

- The model captures multi-exciton effects in energy transfer.
- Inclusion of charge-separation and fluorescence is essential for accurate dynamics.
- Energy and fluorescent currents depend on light intensity.

## Abstract

Usually the study of energy-transfer in the light harvesting complex is limited by a single-exciton motion along the antenna. Starting from the many-body Schr\"odinger equation, we derived Lindblad-type Master equations describing the cyclic exciton-electron dynamics of the light harvesting complex, originated from charge reduction of a donor. These equations, resembling the Master equations for the electric current in mesoscopic systems, go beyond the single-exciton description by accounting for the multi-exciton states accumulated in the antenna, as well as the charge-separation, fluorescence and initial photo-absorption. Although these effects take place on very different time-scales, we demonstrate that their inclusion is necessary for a consistent description of the exciton dynamics. We applied our results to evaluate the energy (exciton) current and for the fluorescent current depending on the light-intensity.