Noise Assisted Excitation Energy Transfer in a Linear Toy Model of a Selectivity Filter Backbone Strand

TL;DR

This study demonstrates that noise can enhance excitation energy transfer efficiency in disordered linear chains, modeling ion channel selectivity filters, by weakening localization effects and involving both classical and quantum effects.

Contribution

It reveals that dephasing noise improves quantum energy transfer efficiency in disordered chains, highlighting the role of noise in biological energy transport structures.

Findings

Noise enhances EET efficiency in disordered chains

Dephasing weakens localization effects

Both classical and quantum effects are necessary for optimal transfer speed

Abstract

In this paper, we investigate the effect of noise and disorder on the efficiency of excitation energy transfer (EET) in a $N=5$ sites linear chain with "static" dipole-dipole couplings. In fact, here, the disordered chain is a toy model for one strand of the selectivity filter backbone in ion channels. It is recently discussed that the presence of quantum coherence in the selectivity filter is possible and can play a role in mediating ion-conduction and ion-selectivity in the selectivity filter. The question is "how a quantum coherence can be effective in such structures while the environment of the channel is dephasing (i.e. noisy)?" Basically, we expect that the presence of the noise should have a destructive effect in the quantum transport. In fact, we show that such expectation is valid for ordered chains. However, our results indicate that introducing the dephasing in the disordered chains leads to the weakening of the localization effects, arising from the randomness, and then increases the efficiency of quantum energy transfer. Thus, the presence of noise is crucial for the enhancement of EET efficiency in disordered chains. We also show that the contribution of both classical and quantum mechanical effects are required to improve the speed of energy transfer along the chain. Our analysis may help for better understanding of fast and efficient functioning of the selectivity filters in ion channels.