Ghosh Anirban, Mandal Sudipta, Chakraborty Dipanjan
Indian Institute of Science Education and Research Mohali, Sec. 81, S.A.S. Nagar, Knowledge City, Manauli, Punjab 140306, India.
J Chem Phys. 2022 Nov 21;157(19):194905. doi: 10.1063/5.0119081.
We have studied the persistence probability p(t) of an active Brownian particle with shape asymmetry in two dimensions. The persistence probability is defined as the probability of a stochastic variable that has not changed its sign in a given fixed time interval. We have investigated two cases: (1) diffusion of a free active particle and (2) that of a harmonically trapped particle. In our earlier work, by Ghosh et al. [J. Chem. Phys. 152, 174901 (2020)], we had shown that p(t) can be used to determine the translational and rotational diffusion constant of an asymmetrically shaped particle. The method has the advantage that the measurement of the rotational motion of the anisotropic particle is not required. In this paper, we extend the study to an active anisotropic particle and show how the persistence probability of an anisotropic particle is modified in the presence of a propulsion velocity. Furthermore, we validate our analytical expression against the measured persistence probability from the numerical simulations of single particle Langevin dynamics and test whether the method proposed in our earlier work can help distinguish between active and passive anisotropic particles.
我们研究了二维中具有形状不对称性的活性布朗粒子的持续概率p(t)。持续概率定义为在给定固定时间间隔内未改变符号的随机变量的概率。我们研究了两种情况：(1)自由活性粒子的扩散和(2)简谐捕获粒子的扩散。在我们早期由戈什等人[《化学物理杂志》152, 174901 (2020)]开展的工作中，我们已经表明p(t)可用于确定不对称形状粒子的平动和转动扩散常数。该方法的优点是不需要测量各向异性粒子的转动运动。在本文中，我们将研究扩展到活性各向异性粒子，并展示在存在推进速度的情况下各向异性粒子的持续概率是如何被修正的。此外，我们根据单粒子朗之万动力学数值模拟测得的持续概率来验证我们的解析表达式，并测试我们早期工作中提出的方法是否有助于区分活性和被动各向异性粒子。
