arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.06176cond-mat.stat-mechcond-mat.soft
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直线上的非交叉旋转粒子

Non-crossing run-and-tumble particles on a line

Pierre Le Doussal, Satya N. Majumdar, Gregory Schehr

摘要:

研究了在无限长直线上以速度$v_0 σ(t)$进行独立运行和翻滚运动的活性粒子,其中$σ(t) = \pm 1$是具有恒定翻转率$γ$的二分电报噪声.我们首先考虑在$x=0$处存在吸收壁的情况下的一个粒子,并且计算它已经存活到时间$t$并且在时间$t$处在位置$x$的概率。然后,我们考虑两个粒子与独立的电报噪声和精确计算的概率,他们不交叉的时间$t$。与被动(布朗)粒子的情况类似,这两个RTP问题不能简化为具有吸收壁的单个RTP。然而,我们能够准确地计算出两个独立的RTP的时间$t$没有交叉的概率,并发现它在大的时间衰减为$t^{-1/2}$的幅度取决于初始条件。后者允许定义一个有效的长度尺度,类似于中子散射中所谓的“米尔恩外推长度”,我们证明这是一个指纹的主动动力学。

英文摘要:

We study active particles performing independent run and tumble motion on an infinite line with velocities $v_0 σ(t)$, where $σ(t) = \pm 1$ is a dichotomous telegraphic noise with constant flipping rate $γ$. We first consider one particle in the presence of an absorbing wall at $x=0$ and calculate the probability that it has survived up to time $t$ and is at position $x$ at time $t$. We then consider two particles with independent telegraphic noises and compute exactly the probability that they do not cross up to time $t$. Contrarily to the case of passive (Brownian) particles this two-RTP problem can not be reduced to a single RTP with an absorbing wall. Nevertheless, we are able to compute exactly the probability of no-crossing of two independent RTP's up to time $t$ and find that it decays at large time as $t^{-1/2}$ with an amplitude that depends on the initial condition. The latter allows to define an effective length scale, analogous to the so called `` Milne extrapolation length'' in neutron scattering, which we demonstrate to be a fingerprint of the active dynamics.

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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