Systematic study of the role of dissipative environment in regulating entanglement and exciton delocalization in the Fenna-Matthews-Olson complex.

In this article, we perform a systematic study of the global entanglement and exciton coherence length dynamics in natural light-harvesting system Fenna-Matthews-Olson (FMO) complex across various parameters of a dissipative environment from low to high temperatures, weak to strong system-environment coupling, and non-Markovian environments. A nonperturbative numerically exact hierarchical equations of motions method is employed to obtain the dynamics of the system. We found that entanglement is driven primarily by the strength of interaction between the system and environment, and it is modulated by the interplay between temperature and non-Markovianity. In contrast, coherence length is found to be insensitive to non-Markovianity. In agreement with previous studies, we do not observe a direct correlation between global entanglement and the efficiency of the excitation energy transfer in the FMO complex. As a new result, we found that the coherence length dynamics is correlated with the excitation energy transfer dynamics.