2025/07/05 by Kalita, Trishna, Sarmah, Manash Jyoti, Akhtar, Javed +1
#Biological Physics (physics.bio-ph) #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2507.04097
We theoretically analyze the Photosystem II reaction center using a quantum master equation approach, where excitonic and charge-transfer rates are computed at the Redfield and Förster levels with realistic spectral densities. The focus is on ergotropy, the maximum work extractable from a quantum state without energy loss. We compute the ergotropy by constructing passive states in the thermodynamic sense. Among the electron transfer pathways, those involving charge separation between ChlD1 and PheD1, as well as a route passing through three sequential charge-separated states, yield higher ergotropy, suggesting greater capacity for work extraction, akin to quantum energy capacitors. A third pathway, bypassing the ChlD1,PheD1 pair, shows significantly reduced ergotropy. These differences arise from population-induced transitions between active and passive regimes. Our findings highlight how biological systems may exploit non-equilibrium population structures to optimize energy conversion, connecting quantum thermodynamic principles to biological energy harvesting.