Role of Energy-Level Mismatches in a Multi-Pathway Complex of Photosynthesis

TL;DR

This paper investigates how energy-level mismatches and quantum noise influence energy transfer efficiency in photosynthetic complexes, revealing conditions that optimize near-perfect transfer by mitigating destructive interference.

Contribution

It demonstrates that asymmetric energy-level mismatches and dephasing noise can significantly enhance energy transfer efficiency in multi-pathway photosynthetic systems, a novel insight into biological energy transport.

Findings

Energy-level mismatches reduce destructive quantum interference.

Dephasing noise further enhances transfer efficiency.

Near-unity efficiency achieved over a range of mismatches.

Abstract

Considering a multi-pathway structure in a light-harvesting complex of photosynthesis, we investigate the role of energy-level mismatches between antenna molecules in transferring the absorbed energy to a reaction center. We find a condition in which the antenna molecules faithfully play their roles: Their effective absorption ratios are larger than those of the receiver molecule directly coupled to the reaction center. In the absence of energy-level mismatches and dephasing noise, there arises quantum destructive interference between multiple paths that restricts the energy transfer. On the other hand, the destructive interference diminishes as asymmetrically biasing the energy-level mismatches and/or introducing quantum noise of dephasing for the antenna molecules, so that the transfer efficiency is greatly enhanced to near unity. Remarkably, the near-unity efficiency can be achieved at a wide range of asymmetric energy-level mismatches. Temporal characteristics are also optimized at the energy-level mismatches where the transfer efficiency is near unity. We discuss these effects, in particular, for the Fenna-Matthews-Olson complex.