Coarse-grained representation of the quasi adiabatic propagator path integral for the treatment of non-Markovian long-time bath memory.
Coarse-grained representation of the quasi adiabatic propagator path integral for the treatment of non-Markovian long-time bath memory.
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DOI：
10.1063/1.4984075
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发表时间：
2017-06
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影响因子：
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通讯作者：
Martin Richter;B. Fingerhut
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文献类型：
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作者：
Martin Richter;B. Fingerhut
对于基于路径积分的方法，如迭代准绝热传播子路径积分(IQUAPI)方法，低频浴模施加的非马尔可夫效应的描述是一个持久的挑战。我们提出了一种新的近似方法，称为掩码辅助影响系数粗粒化(MACGIC)-iQUAPI，由于考虑的传播路径段的大幅减少，该方法提供了引人注目的计算节省。该方法依赖于一种有效的路径段合并过程，该过程通过利用系统退相干的物理特性的费曼-弗农影响系数的中间粗粒度表示。MACGIC-iQUAPI方法允许我们在保持收敛到iQUAPI结果的同时，访问数百个传播时间步长量级的生物显著长时间浴记忆的机制。对一组基准问题进行了数值模拟，包括浴辅助的长程电子转移，典型分子二聚体中从相干动力学到非相干动力学的转变，以及Fenna-Matthews-Olson三聚体的24态模型中的激发能量转移，在所有情况下都与数值精确的参考数据获得了很好的一致。
The description of non-Markovian effects imposed by low frequency bath modes poses a persistent challenge for path integral based approaches like the iterative quasi-adiabatic propagator path integral (iQUAPI) method. We present a novel approximate method, termed mask assisted coarse graining of influence coefficients (MACGIC)-iQUAPI, that offers appealing computational savings due to substantial reduction of considered path segments for propagation. The method relies on an efficient path segment merging procedure via an intermediate coarse grained representation of Feynman-Vernon influence coefficients that exploits physical properties of system decoherence. The MACGIC-iQUAPI method allows us to access the regime of biological significant long-time bath memory on the order of hundred propagation time steps while retaining convergence to iQUAPI results. Numerical performance is demonstrated for a set of benchmark problems that cover bath assisted long range electron transfer, the transition from coherent to incoherent dynamics in a prototypical molecular dimer and excitation energy transfer in a 24-state model of the Fenna-Matthews-Olson trimer complex where in all cases excellent agreement with numerically exact reference data is obtained.