Does coherence enhance transport in photosynthesis?

Abstract

Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding incoherent processes.

7 pages

References in corpus (6)

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• Memory-assisted exciton diffusion in the chlorosome light-harvesting antenna of green sulfur bacteria
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Cited by in corpus (11)

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• Structure-Dynamics Relation in Physically-Plausible Multi-Chromophore Systems
• Practical Witness for Electronic Coherences
• Dynamics of coherence, localization and excitation transfer in disordered nanorings
• Photochemical dynamics under incoherent illumination: light harvesting in self-assembled molecular J-aggregates
• Quantifying fermionic decoherence in many-body systems
• Quantum transport in non-Markovian dynamically-disordered photonic lattices
• Excitation relaxation in molecular chain and energy transfer at steady state