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arXiv 2004.05414math.PRphysics.bio-phq-bio.QM
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扩散过程中慢区和快区对极端首次通过时间的竞争

Competition between slow and fast regimes for extreme first passage times of diffusion

Jacob B. Madrid, Sean D. Lawley

摘要:

许多物理、化学和生物系统都依赖于扩散介质到达靶点的首次通过时间(FPT)。通常,该FPT比特征扩散时间尺度慢得多。例如,如果目标很小(窄逃逸问题),或者如果目标必须逃离势阱,情况就是这样。然而,许多系统依赖于搜索者第一次从一大群搜索者中找到目标,这就是所谓的极端FPT。由于这种极端的FPT在许多搜索者的限制下消失,因此可以通过部署足够的搜索者来否定扩散搜索的慢得令人望而却步的FPT。然而,人们对“足够的搜索者”这一概念理解甚少。如何确定一个系统是处于慢态(例如,由小目标或深势主导)还是快态(由许多搜索者主导)?如何估计这些不同制度下的极端FPT?在本文中,我们回答这些问题,推导条件,确保系统是在任何政权,并找到近似的全分布和所有的时刻,在这些制度的极端FPT。我们的分析揭示了临界效应,初始的FPT分布和目标反应性可以有极端FPT。

英文摘要:

Many physical, chemical, and biological systems depend on the first passage time (FPT) of a diffusive searcher to a target. Typically, this FPT is much slower than the characteristic diffusion timescale. For example, this is the case if the target is small (the narrow escape problem) or if the searcher must escape a potential well. However, many systems depend on the first time a searcher finds the target out of a large group of searchers, which is the so-called extreme FPT. Since this extreme FPT vanishes in the limit of many searchers, the prohibitively slow FPTs of diffusive search can be negated by deploying enough searchers. However, the notion of "enough searchers" is poorly understood. How can one determine if a system is in the slow regime (dominated by small targets or a deep potential, for example) or the fast regime (dominated by many searchers)? How can one estimate the extreme FPT in these different regimes? In this paper, we answer these questions by deriving conditions which ensure that a system is in either regime and finding approximations of the full distribution and all the moments of the extreme FPT in these regimes. Our analysis reveals the critical effect that initial searcher distribution and target reactivity can have on extreme FPTs.

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。

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