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arXiv 2409.02496physics.chem-phcond-mat.otherquant-ph
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多发色团系统中激发能转移动力学的自洽方法

Self-consistent approach to the dynamics of excitation energy transfer in multichromophoric systems

Veljko Janković, Tomáš Mančal

AI总结:

针对分子聚集体激子输运研究中超越最低阶玻恩近似导致的复杂发散问题,提出刘维尔空间频域的自洽玻恩近似以重新求和微扰级数,其在多参数范围与分层运动方程吻合良好,能合理描述现实环境下的激子动力学。

摘要:

计算上易于处理且可靠(尽管是近似的)的方法,用于研究浸没在结构化玻色环境中的分子聚集体中的激子输运,已得到积极发展。超越量子主方程记忆核的最低阶(玻恩)近似通常会导致复杂且可能发散的表达式。从玻恩近似下的记忆核出发,并将量子主方程视为格林函数理论的戴森方程,我们构建了自洽玻恩近似,以按激子-环境相互作用的幂次重新求和记忆核微扰级数。我们的公式在刘维尔空间和频域中,可处理任意激子-环境谱密度。在耦合到过阻尼振荡器环境的分子二聚体中,我们发现自洽循环显著改善了玻恩近似下的能量转移动力学。自洽玻恩近似的动力学与分层运动方程的解在广泛参数范围内吻合良好,包括强激子-环境相互作用、慢环境和低温等最具挑战性的区域。这通过纯退相干模型中相干-退相干动力学的分析考虑得到了合理化。我们发现,自洽玻恩近似在描述由与激子能隙共振(非共振)的欠阻尼振动调制的能量转移时表现良好(较差)。尽管如此,它仍能合理描述Fenna-Matthews-Olson复合物的七位点模型在包含过阻尼连续体和欠阻尼振动的现实环境中的激子动力学。

英文摘要:

Computationally tractable and reliable, albeit approximate, methods for studying exciton transport in molecular aggregates immersed in structured bosonic environments have been actively developed. Going beyond the lowest-order (Born) approximation for the memory kernel of the quantum master equation typically results in complicated and possibly divergent expressions. Starting from the memory kernel in the Born approximation, and recognizing the quantum master equation as the Dyson equation of Green's functions theory, we formulate the self-consistent Born approximation to resum the memory-kernel perturbation series in powers of the exciton--environment interaction. Our formulation is in the Liouville space and frequency domain and handles arbitrary exciton--environment spectral densities. In a molecular dimer coupled to an overdamped oscillator environment, we conclude that the self-consistent cycle significantly improves the Born-approximation energy-transfer dynamics. The dynamics in the self-consistent Born approximation agree well with the solutions of hierarchical equations of motion over a wide range of parameters, including the most challenging regimes of strong exciton--environment interactions, slow environments, and low temperatures. This is rationalized by the analytical considerations of coherence-dephasing dynamics in the pure-dephasing model. We find that the self-consistent Born approximation is good (poor) at describing energy transfer modulated by an underdamped vibration resonant (off-resonant) with the exciton energy gap. Nevertheless, it reasonably describes exciton dynamics in the seven-site model of the Fenna--Matthews--Olson complex in a realistic environment comprising both an overdamped continuum and underdamped vibrations.

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