arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2303.03078cond-mat.stat-mechcond-mat.softphysics.bio-ph
收藏

捕获环境中的跑动-翻滚运动

Run-and-tumble motion in trapping environments

Luca Angelani

AI总结:

本文研究活性粒子在含捕获区域环境中的跑动-翻滚运动,求解一维动力学方程,给出稳态分布和平均捕获时间,并扩展模型以解释细菌黏附中的亚扩散行为。

摘要:

复杂或不利的环境有时会抑制扩散粒子或活性游动者的运动能力,使其可能被困在固定位置。例如,在生物膜形成初期细菌黏附到表面的过程中就会出现这种情况。本文分析了存在捕获区域时活性粒子的动力学,其中粒子会以固定速率发生不可逆的固定化。通过求解一维空间中跑动-翻滚运动的动力学方程,我们给出了概率分布函数的表达式,重点关注被阻塞粒子的稳态分布以及用物理和几何参数表示的平均捕获时间。我们考虑了捕获区域的不同扩展形式,从无限区域到半无限和有限区间的情形。对于无限延伸的捕获区域,平均捕获时间恰好等于捕获速率的倒数;而在半无限情形下,平均捕获时间具有非平凡的形式;在有限区域中,由于捕获时间分布出现长尾,平均捕获时间未定义。最后,为了解释细菌黏附到表面过程中观察到的亚扩散行为,我们将模型扩展为在捕获区域内包含反常扩散运动,并报告了均方位移的精确表达式。

英文摘要:

Complex or hostile environments can sometimes inhibit the movement capabilities of diffusive particles or active swimmers, who may thus become stuck in fixed positions. This occurs, for example, in the adhesion of bacteria to surfaces at the initial stage of biofilm formation. Here we analyze the dynamics of active particles in the presence of trapping regions, where irreversible particle immobilization occurs at a fixed rate. By solving the kinetic equations for run-and tumble motion in one space dimension, we give expressions for probability distribution functions, focusing on stationary distributions of blocked particles, and mean trapping times in terms of physical and geometrical parameters. Different extensions of the trapping region are considered, from infinite to cases of semi infinite and finite intervals. The mean trapping time turns out to be simply the inverse of the trapping rate for infinitely extended trapping zones, while it has a nontrivial form in the semi-infinite case and is undefined for finite domains, due to the appearance of long tails in the trapping time distribution. Finally, to account for the subdiffusive behavior observed in the adhesion processes of bacteria to surfaces, we extend the model to include anomalous diffusive motion in the trapping region, reporting the exact expression of the mean-square displacement.

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。

↑