Decoherence dynamics of coherent electronic excited states in the photosynthetic purple bacterium Rhodobacter sphaeroides.
In this paper, we present a theoretical description to the quantum coherence and decoherence phenomena of energy transfer in photosynthesis observed in a recent experiment [Science 316, 1462 (2007)]. As a successive two-color laser pulses with selected frequencies cast on a sample of the photosynthetic purple bacterium Rb. sphaeroides two resonant excitations of electrons in chromophores can be generated. However, this effective two-level subsystem will interact with its protein environment and decoherence is inevitable. We describe this subsystem coupled with its environment as a dynamical spin-boson model. The non-Markovian decoherence dynamics is described using a quasiadiabatic propagator path integral (QUAPI) approach. With the photon-induced effective time-dependent level splitting energy and level flip coupling coefficient between the two excited states and the environment-induced non-Markovian decoherence dynamics, our theoretical result is in good agreement with the experimental data.
Liang
Xian-Ting
XT
Department of Physics and Institute of Modern Physics, Ningbo University, Ningbo, 315211, China. xtliang@ustc.edu
Zhang
Wei-Min
WM
Zhuo
Yi-Zhong
YZ
D000465:Algorithms; D003198:Computer Simulation; D004583:Electrons; D007834:Lasers; D008954:Models, Biological; D017785:Photons; D010788:Photosynthesis / Q000502:physiology*; D012242:Rhodobacter sphaeroides