Control of Excitation Energy Transfer in Condensed Phase Molecular Systems by Floquet Engineering

TL;DR

This paper demonstrates that Floquet engineering, through periodic modulation of excitation energy differences, can significantly enhance excitation energy transfer rates in molecular systems, even amidst environmental fluctuations and dissipation.

Contribution

It introduces a method to control EET rates via Floquet engineering, showing analytical and numerical evidence of effectiveness despite environmental noise.

Findings

EET rate can be greatly enhanced by periodic modulation.

Optimal driving frequency depends on environmental fluctuation timescales.

Floquet engineering remains effective under strong environmental fluctuations.

Abstract

Excitation energy transfer (EET) is one of the most important processes in both natural and artificial chemical systems including, for example, photosynthetic complexes and organic solar cells. The EET rate, however, is strongly suppressed when there is a large difference in the excitation energy between the donor and acceptor molecules. Here, we demonstrate both analytically and numerically that the EET rate can be greatly enhanced by periodically modulating the excitation energy difference. The enhancement of EET by using this Floquet engineering, in which the system's Hamiltonian is made periodically time-dependent, turns out to be efficient even in the presence of strong fluctuations and dissipations induced by the coupling with a huge number of dynamic degrees of freedom in the surrounding molecular environments. As an effect of the environment on the Floquet engineering of EET, the optimal driving frequency is found to depend on the relative magnitudes of the system and environment's characteristic time scales with an observed frequency shift when moving from the limit of slow environmental fluctuations (inhomogeneous broadening limit) to that of fast fluctuations (homogeneous broadening limit).