Persistence of an active asymmetric rigid Brownian particle in two dimensions

TL;DR

This paper investigates how the persistence probability of an asymmetric active Brownian particle in two dimensions is affected by propulsion, extending previous work to active particles and validating results through simulations.

Contribution

It extends the analysis of persistence probability to active asymmetric particles, showing how propulsion modifies this probability and validating the approach with numerical simulations.

Findings

Persistence probability is altered by propulsion velocity.

Method can distinguish active from passive particles.

Analytical results agree with numerical simulations.

Abstract

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 the probability of a stochastic variable that has not changed it's sign in the fixed given time interval. We have investigated two cases: diffusion of a free active particle and that of harmonically trapped particle. In our earlier work, \emph{Ghosh et. al.}, Journal of Chemical Physics, \textbf{152},174901, (2020), we had shown that $p(t)$ can be used to determine translational and the rotational diffusion constant of an asymmetric shape particle. The method has the advantage that the measurement of the rotational motion of the an-isotropic particle is not required. In this paper, we extend the study to an active an-isotropic particle and show how the persistence probability of an an-isotropic particle is modified in the presence of a propulsion velocity. Further, 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 distinguish between an active and a passive an-isotropic particle.