講座主題：Piecewise ensemble averaging stochastic Liouville equations for simulating non-Markovian quantum dynamics
專家姓名：嚴運安
工作單位：魯東大學
講座時間：2022年8月29日10:00-11:00
講座地點：物電學院1511報告廳
主辦單位：煙臺大學物理與電子信息學院
內容摘要：
The stochastic scheme is a fruitful tool for simulating the challenging non-Markovian quantum dynamics. Its performance at long time, however, degrades due to the intrinsic fast increase in the variance of the quantum Brownian motion. This talk presents the recent progress on developing the stochastic Liouville equations with piecewise stationary noises. Starting from a conventional stochastic scheme, we can always decompose the involved noises into two parts: the principal part assuming piecewise correlations and the auxiliary part recovering the full correlation. A partial stochastic average over the auxiliary noises yields a stochastic Liouville equation that only involves noises with piecewise correlations and can hence be averaged separatedly for different time intervals. Meanwhile the dissipative influence of the auxiliary noises is rigorously incorporated with integrals over the functional derivatives with respect to the principal noises. The working equation now assumes a similar structure to the non-Markovian quantum state diffusion. Thanks to the noise disentanglement in different time intervals, we can perform piecewise ensemble average and serve the average of the preceding interval as the initial condition of the subsequent propagation. This strategy avoids the long-time stochastic average and the corresponding statistical errors will be saturated at long times. This talk will give numerical results for the spontaneous decay of two-state atoms and the spin-boson model and shows that the suggested method enables us to simulate the long-time quantum dissipative dynamics with long memories in the non-perturbative regime.
主講人介紹：
嚴運安，魯東大學教授。2002年于中國科學院理論物理研究所獲博士學位,，2002-2012年,，先后在中國科學院化學研究所、美國德克薩斯理工大學,、德國柏林自由大學,、德國羅斯托克大學和日本九州大學進行博士后和訪問學者研究，2012年加入貴州師范學院,，2018年加入魯東大學,。嚴運安教授目前的研究方向是發(fā)展新方法模擬凝聚相中分子體系的耗散動力學。
