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Do we live in a Quantum World? Coherent multidimensional studies of quantum coherence effects in biological systems
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主講人: Dwayne Miller(University of Toronto, Canada)
地點: 物理樓中215 Zoom:84554582958 Passcode: 2021
時間: 2021/12/02 (星期四 Thursday) 8:30-9:30 (Beijing Time)
主持 聯系人: 李铮 (zheng.li@pku.edu.cn)
主講人簡介: R. J. Dwayne Miller 教授是加拿大多倫多大學學院教授(University Professor),2010年-2019年任德國馬克斯普朗克物質結構與動力學研究所所長(Max Planck Director),在超快光物理和分子物理領域享有盛譽。Miller教授是超快電子衍射技術的開創者之一,曾獲得歐洲物理學會激光科學獎,皇家化學會百年紀念獎(Centenary Prize),皇家化學會盧瑟福獎章(Rutherford Medal),在超快分子動力學領域發表論文300餘篇,其中包括Nature和Science正刊10篇

The relative importance of quantum coherence effects in biological systems has long been debated. At the molecular level, the discussion reduces to the spatial and temporal coherence of the corresponding wavefunction describing the biological response function. This talk will briefly explore the biological functions of energy transport in photosynthetic systems and photoisomerization processes to provide two different examples ofevolutionarlyoptimization. The focus will be on the photoisomerization process of rhodopsin (Rh) and bacteriorhodopsin (bR). In 2D spectra for Rh andbR, we observe very strong modulation of spectra related to the reactant/product surfaces by the very modes involved in the structural transition. In the case of Rh, the steric repulsive forces of the excited cis conformation state impulsively direct the system to the conical intersection (CI) within a half period of the localized C11-C12 bond, the key torsional motion directing the isomerization. InbR, the trans conformation allows exploration of larger nuclear configuration phase space; yet strong vibrational coherences are still observed. By comparison to multi-configuration quantum chemistry calculations, we assign this unusual nuclear-electronic coupling to principally the bond elongation coordinate periodically mixing the S1 and S2 electronic surfaces. It is this coupling that dynamically directs the photoisomerization inbR.Nature has found 2 solutions to beat rapid intramolecular vibrational redistribution processes for such high vibrational density of states that normally occur within 100 fs time scales. The vibrational coupling to electronic surfaces and imposed direction is dissipation driven. Nature does not try to engineer the protein/bath to conserve coherences but rather exploits dissipation to direct biological processes. This simple concept, mastered by nature over all relevant time and spatial dimensions is truly the marvel of biology.