Dissipative Dynamics Of The Core Pigments In Photosystem Ⅱ Reaction Center

Photosynthesis is one of the most important processes in biological systems,by which plants convert sunlight energy into chemical energy.The antenna absorbs light energy and transfers the energy to the reaction center.The pigment molecules in the reaction center are excited upon receiving energy or directly absorbing the sunlight photons.The excited state energy of the pigment in the reaction center is then converted to chemical energy by electron transfer.Excitation energy transfer(EET)and electron transfer(ET)are crucially involved in photosynthetic processes.In particular,many experimental and theoretical studies reveal that quantum coherence may play an important role on EET and ET processes in the photosynthetic reaction center.The core complex is the main participant in the EET and ET of the reaction center.In reality,the photosynthetic reaction center core complex constitutes an open quantum system,which manifests an interplay between pigments and light/phonon baths.The involved dynamics is non-Markovian due to that the coupling strength between pigments and the environment is comparable to that between pigments,as well as the timescale of EET is around that of the bath memory.However,so far the theoretical studies are mainly based on some approximate or phenomenological methods which do not include non-Markovian effects.In this thesis,we investigate this open system via two quantum dissipation methods on basic of a five-level model.We adopt the dissipaton-equation-of-motion and Lindblad quantum master equation methods.The former is a non-Markovian and nonperturbative approach while the latter is based on the second-order Born expansion and does not include non-Markovian effects.The non-Markovian effect is demonstrated via the comparison between numerical results of these two approaches.Besides,the influences of coupling strengths between pigments and the cross-correlation of different bath coupling modes are also exhibited based on dissipaton equation of motion simulation.By taking dissipaton-equation-of-motion as a calibration,we compare the accuracy of chronological ordering prescriptio and correlated driving-and-dissipation quantum master equations by evaluating the non-Condon spectroscopies of a modeled biexcition system.