Abstract :
[en] Targeted exciton transport is crucial for efficient light-harvesting, but its microscopic description in biological systems is complicated by strong environmental
coupling, highly structured vibrational environments and non-Markovian open system dynamics. In this article we employ the non-perturbative hierarchical
equations of motion (HEOM) technique to explore how structured environments and tuned electronic properties can lead to the generation of coherent motion across
a directed transport network, i.e. one containing an energy gradient. By further exploiting the information contained in the auxiliary HEOM matrices, we also
visualize the complete displacement distributions of the main reaction coordinate during the ultrafast relaxation, and show that highly non-Gaussian profiles emerge
when the electronic dynamics become quasi-reversible and involve bath-induced delocalized states. These coherent dynamics are spontaneously generated by earlier
incoherent relaxation events, and we also demonstrate the correlation between the environmental coordinates and a quantitative volume-based measure of non-
Markovianity.
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