Noise-Assisted Discord-Like Correlations in Light-Harvesting Photosynthetic Complexes

TL;DR

This paper investigates how quantum discord-like correlations, beyond entanglement, enhance energy transport efficiency in photosynthetic complexes, revealing their role in the Environment-Assisted Quantum Transport phenomenon.

Contribution

It demonstrates that quantum discord correlates with transport efficiency in light-harvesting complexes, providing new insights beyond traditional entanglement-focused studies.

Findings

Quantum discord peaks when transport efficiency is high.

Entanglement vanishes as discord peaks.

Quantum discord acts as a signature of ENAQT.

Abstract

Transport phenomena in photosynthetic systems have attracted a great deal of attention due to their potential role in devising novel photovoltaic materials. In particular, energy transport in light-harvesting complexes is considered quite efficient due to the balance between coherent quantum evolution and decoherence, a phenomenon coined Environment-Assisted Quantum Transport (ENAQT). Although this effect has been extensively studied, its behavior is typically described in terms of the decoherence's strength, namely weak, moderate or strong. Here, we study the ENAQT in terms of quantum correlations that go beyond entanglement. Using a subsystem of the Fenna-Matthews-Olson complex, we find that discord-like correlations maximize when the subsystem's transport efficiency increases, while the entanglement between sites vanishes. Our results suggest that quantum discord is a manifestation of the ENAQT and highlight the importance of beyond-entanglement correlations in photosynthetic energy transport processes.