Quantum Coherence in Biological Light Harvesting: Role, Mechanism, and Significance

Photosynthesis is a remarkably efficient molecular process that converts solar energy into chemical energy by transferring excitation energy towards reaction centres. Understanding this energy transfer at the microscopic molecular level is an interdisciplinary problem connecting topics as diverse as quantum physics, physical chemistry, molecular biology, and biophysics. The possible role of quantum coherence has been highlighted repeatedly, particularly for light-harvesting complexes, and it remains an actively debated question, with several research groups advancing alternative concepts. Coherent superpositions of electronic excitations are widely thought to influence the efficiency and pathways of excitation-energy transport, which raises a central question: over what timescales must coherence persist for energy transfer to occur?Work in this area centres on electronic coupling between chromophores, excitonic interactions, delocalised excitonic states, and how these states evolve following photoexcitation. The scope spans both theory/computation and experiment, and extends beyond protein complexes such as the Fenna–Matthews–Olson (FMO) complex to the other photosynthetic antenna complexes common in biological environments.The goal of this Research Topic is to clarify the physical mechanisms underlying efficient excitation-energy transfer in photosynthetic light-harvesting systems, and to establish the conditions under which quantum coherence contributes to that efficiency.Specific objectives include:• determining the timescales over which coherence persists in excitation-energy transfer• establishing the physical conditions for coherence, and delineating coherent and incoherent transfer regimes for efficient excitation transport• assessing the effects of environmental fluctuations, vibrational motion, temperature, and system-bath interactions, given that biological light-harvesting systems operate in noisy, dynamically fluctuating environments• advancing theoretical and computational treatments based on exciton Hamiltonians, density-matrix formalisms, Förster-type energy-transfer models, (modified) Redfield theories, and numerically exact or approximate open-quantum-system methodsBy achieving these goals, this collection aims to deepen our insight into the fundamental principles governing photosynthetic energy conversion, and to inform the design of artificial light-harvesting materials, bio-inspired photonic systems, and quantum-enabled energy-transfer technologies.This Research Topic welcomes contributions that advance the physical understanding of excitation-energy transfer in photosynthetic and bio-inspired light-harvesting systems. Themes of interest include, but are not limited to:• Quantum coherence, decoherence, and coherence timescales in excitation-energy transfer• Electronic coupling, excitonic interactions, and delocalised excitonic states• Coherent and incoherent energy-transfer regimes and transport efficiency• Exciton–vibrational (vibronic) coupling, environmental noise, temperature, and system–bath interactions• Open-quantum-system approaches: density-matrix formalisms, Förster and (modified) Redfield theories, and numerically exact methods• Ultrafast spectroscopy and experimental probes of energy-transfer dynamics• Light-harvesting complexes beyond FMO, including other photosynthetic antenna systems• Artificial light-harvesting materials, bio-inspired photonic systems, and quantum-enabled energy technologiesWe invite Original Research, Review, Methods, Mini Review, and Perspective articles. All contributions must advance the physical understanding of excitation-energy transfer in light-harvesting systems and demonstrate clear relevance to the mechanisms of photosynthetic energy conversion. Topic editors: Diptesh Dey, Ahmed A. Heikal, Raffaele Borrelli Source: https://www.frontiersin.org/research-topics/84852/quantum-coherence-in-biological-light-harvesting-role-mechanism-and-significance