Quantum coherent biomolecular energy transfer with spatially correlated fluctuations

TL;DR

This paper investigates how spatially correlated environmental fluctuations influence quantum coherent energy transfer in biomolecules, revealing conditions that suppress or enhance decoherence depending on environmental mode wavelengths and temperature.

Contribution

It introduces a simple model to analyze the impact of spatial correlations on quantum energy transfer and explores how environmental parameters affect decoherence.

Findings

Spatial correlations can suppress decoherence when environmental mode wavelengths exceed chromophore separation.

Propagating environmental modes can extend correlation ranges, affecting energy transfer.

Increasing temperature can counteract the decoherence effects of environmental correlations.

Abstract

We show that the quantum coherent transfer of excitations between biomolecular chromophores is strongly influenced by spatial correlations of the environmental fluctuations. The latter are due either to propagating environmental modes or to local fluctuations with a finite localization length. A simple toy model of a single donor-acceptor pair with spatially separated chromophore sites allows to investigate the influence of these spatial correlations on the quantum coherent excitation transfer. The sound velocity of the solvent determines the wave lengths of the environmental modes, which, in turn, has to be compared to the spatial distance of the chromophore sites. When the wave length exceeds the distance between donor and acceptor site, we find strong suppression of decoherence. In addition, we consider two spatially separated donor-acceptor pairs under the influence of propagating environmental modes. Depending on their wave lengths fixed by the sound velocity of the solvent material, the spatial range of correlations may extend over typical interpair distances, which can lead to an increase of the decohering influence of the solvent. Surprisingly, this effect is counteracted by increasing temperature.