Do photosynthetic complexes use quantum coherence to increase their efficiency? Probably not

Zerah-Harush, Elinor

doi:10.1126/sciadv.abc4631

Cited by 31 publications

(20 citation statements)

References 76 publications

(105 reference statements)

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“…The exciton coherence has generated much interest in quantum biology owing to discovery of coherent oscillations in exciton-transfer complexes, which led to an assumption that quantum coherence drives an energy transfer in natural photosynthetic complexes, making them extremely efficient. − …”

Section: The Excitonic “Zoo” In Organic Materialsmentioning

confidence: 99%

Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems

2022

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The exciton, an excited electron–hole pair bound by Coulomb attraction, plays a key role in photophysics of organic molecules and drives practically important phenomena such as photoinduced mechanical motions of a molecule, photochemical conversions, energy transfer, generation of free charge carriers, etc. Its behavior in extended π-conjugated molecules and disordered organic films is very different and very rich compared with exciton behavior in inorganic semiconductor crystals. Due to the high degree of variability of organic systems themselves, the exciton not only exerts changes on molecules that carry it but undergoes its own changes during all phases of its lifetime, that is, birth, conversion and transport, and decay. The goal of this review is to give a systematic and comprehensive view on exciton behavior in π-conjugated molecules and molecular assemblies at all phases of exciton evolution with emphasis on rates typical for this dynamic picture and various consequences of the above dynamics. To uncover the rich variety of exciton behavior, details of exciton formation, exciton transport, exciton energy conversion, direct and reverse intersystem crossing, and radiative and nonradiative decay are considered in different systems, where these processes lead to or are influenced by static and dynamic disorder, charge distribution symmetry breaking, photoinduced reactions, electron and proton transfer, structural rearrangements, exciton coupling with vibrations and intermediate particles, and exciton dissociation and annihilation as well.

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Section: The Excitonic “Zoo” In Organic Materialsmentioning

confidence: 99%

Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems

2022

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“…Studies have also shown that the coherence might be helpful in transport dynamics, but it does not contribute to the high efficiency of this exciton energy transport dynamics . Another recent study argues that the contribution from quantum coherence is minute at best in photosynthesis transport processes . Other than quantum coherence, quantum features like entanglement and quantum memory effects (non-Markovianity) have been explored additionally to find their impacts on this highly efficient transport process.…”

Section: Introductionmentioning

confidence: 99%

Non-Markovianity between Site Pairs in FMO Complex Using Discrete-Time Quantum Jump Model

Kundu

Chandrashekar

2022

ACS Omega

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The Fenna–Mathews–Olson (FMO) complex present in green sulfur bacteria is known to mediate the transfer of excitation energy between light-harvesting chlorosomes and membrane-embedded bacterial reaction centers. Due to the high efficiency of this transport process, it is an extensively studied pigment–protein complex system with the eventual aim of modeling and engineering similar dynamics in other systems and using it for real-time application. Some studies have attributed the enhancement of transport efficiency to wavelike behavior and non-Markovian quantum jumps resulting in long-lived and revival of quantum coherence, respectively. Since dynamics in these systems reside in the quantum-classical regime, quantum simulation of such dynamics will help in exploring the subtle role of quantum features in enhancing the transport efficiency, which has remained unsettled. Discrete simulation of the dynamics in the FMO complex can help in efficient engineering of the heat bath and controlling the environment with the system. In this work, using the discrete quantum jump model we show and quantify the presence of higher non-Markovian memory effects in specific site pairs when internal structures and environmental effects are in favor of faster transport. As a consequence, our study leans toward the connection between non-Markovianity in quantum jumps with the enhancement of transport efficiency.

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“…For over a decade, a lot of work has exposed the mechanisms of environmental noise-assisted quantum transport (ENAQT) [8][9][10][11][12], a phenomenon describing how incoherent processes from interactions with the environment around a system can improve energy transport in quantum systems. This work was heavily motivated by the possible connection between ENAQT and the efficiency of photosynthesis [1,3,[8][9][10][13][14][15], though recent work suggests the relationship between the two may be more nuanced [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Localisation determines the optimal noise rate for quantum transport

Coates

Lovett²,

Gauger³

2021

New J. Phys.

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Environmental noise plays a key role in determining the efficiency of transport in quantum systems. However, disorder and localisation alter the impact of such noise on energy transport. To provide a deeper understanding of this relationship we perform a systematic study of the connection between eigenstate localisation and the optimal dephasing rate in 1D chains. The effects of energy gradients and disorder on chains of various lengths are evaluated and we demonstrate how optimal transport efficiency is determined by both size-independent, as well as size-dependent factors. By discussing how size-dependent influences emerge from finite size effects we establish when these effects are suppressed, and show that a simple power law captures the interplay between size-dependent and size-independent responses. Moving beyond phenomenological pure dephasing, we implement a finite temperature Bloch-Redfield model that captures detailed balance. We show that the relationship between localisation and optimal environmental coupling strength continues to apply at intermediate and high temperature but breaks down in the low temperature limit.

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Do photosynthetic complexes use quantum coherence to increase their efficiency? Probably not

Cited by 31 publications

References 76 publications

Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems

Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems

Non-Markovianity between Site Pairs in FMO Complex Using Discrete-Time Quantum Jump Model

Localisation determines the optimal noise rate for quantum transport

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