arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0705.2358cond-mat.stat-mechcond-mat.soft
收藏

非马氏随机Liouville方程及其马氏表示连续时间随机游走方法的扩展

Non-Markovian Stochastic Liouville equation and its Markovian representation. Extensions of the continuous time random walk approach

A. I. Shushin

摘要:

在马尔可夫表示(MR)和基于连续时间随机游走(CTRW)的非马尔可夫随机Liouville方程(SLE)模型下,详细分析了CTRW方法的一些特性和扩展.在MR CTRW过程表示的多维马尔可夫的。在这种表示中,涨落更新的概率分布函数(PDF)W(t)与某些马尔可夫控制过程的某个跳变状态中重现的概率分布函数相关联。在MR的非马尔可夫SLE,它描述了CTRW样的噪声对放松的动态和随机系统的影响,广义考虑到放松系统的噪声的统计特性的影响。广义非马尔可夫SLE的CTRW方法研究两个修改。其中之一认为,级联CTRW中的控制过程实际上是CTRW一样的一个控制的另一个CTRW过程,控制,反过来由第三个,等等。在MR的简单表达式的PDF W(t)的总控制过程中得到的马尔可夫变量的控制PDF的级联。该表达式在由长时间尾W(t)决定的异常过程的情况下特别简单和有指导意义。级联CTRW可以模拟系统的复杂性对弛豫动力学的影响(在玻璃,分形,分支介质,超度量结构等)。另一种CTRW修正描述了由波动W(t)控制的过程的动力学。在MR的问题进行了分析,在一个一般的形式,没有限制性的假设连续更新的PDF的相关性。分析表明,W(t)可以强烈地影响该过程的动力学。这种影响的可能表现进行了讨论。

英文摘要:

Some specific features and extensions of the continuous time random walk (CTRW) approach are analyzed in detail within the Markovian representation (MR) and CTRW-based non-Markovian stochastic Liouville equation (SLE). In the MR CTRW processes are represented by multidimensional Markovian ones. In this representation the probability distribution function (PDF) W(t) of fluctuation renewals is associated with that of reoccurrences in a certain jump state of some Markovian controlling process. Within the MR the non-Markovian SLE, which describes the effect of CTRW-like noise on relaxation of dynamic and stochastic systems, is generalized to take into account the influence of relaxing systems on statistical properties of noise. The generalized non-Markovian SLE is applied to study two modifications of the CTRW approach. One of them considers the cascaded CTRWs in which the controlling process is actually CTRW-like one controlled by another CTRW process, controlled in turn by the third one, etc. Within the MR simple expression for the PDF W(t) of total controlling process is obtained in terms of Markovian variants of controlling PDFs in the cascade. The expression is shown to be especially simple and instructive in the case of anomalous processes determined by long time tailed W(t). The cascaded CTRWs can model the effect of complexity of a system on relaxation kinetics (in glasses, fractals, branching media, ultrametric structures, etc.). Another CTRW-modification describes the kinetics of processes governed by fluctuating W(t). Within the MR the problem is analyzed in a general form without restrictive assumptions on correlations of PDFs of consecutive renewals. The analysis shows that W(t) can strongly affect the kinetics of the process. Possible manifestations of this effect are discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑