Statistics of percolating clusters in a model of photosynthetic bacteria

TL;DR

This study models the percolation transition in photosynthetic bacteria by simulating exciton migration and analyzing the critical properties of the resulting percolating clusters, revealing insights into energy transfer dynamics.

Contribution

It introduces a correlated percolation model for exciton dynamics in photosynthetic bacteria and characterizes the critical properties of the percolation transition through Monte Carlo simulations.

Findings

Identification of the critical threshold $x_c$ for percolation.

Measurement of the spanning probability near $x_c$.

Analysis of fractal properties of the percolating cluster.

Abstract

In photosynthetic organisms, the energy of light during illumination is absorbed by the antenna complexes, which is transmitted by excitons and is either absorbed by the reaction centers (RCs), which have been closed in this way, or emitted by fluorescence. The basic components of the dynamics of light absorption have been integrated into a simple model of exciton migration, which contains two parameters: the exciton hopping probability and the exciton lifetime. During continuous radiation with light the fraction of closed RCs, $x$, continuously increases and at a critical threshold, $x_c$, a percolation transition takes place. Performing extensive Monte Carlo simulations we study the properties of the transition in this correlated percolation model. We measure the spanning probability in the vicinity of $x_c$, as well as the fractal properties of the critical percolating cluster, both in the bulk and at the surface.