Alternative escape for run-and-tumble particles from a potential with spatially random perturbations

Abstract

The dynamics of self-propelled particles are naturally affected by both spatial and temporal perturbations due to the disordered landscapes and thermal fluctuations in their living environment. Here, we investigate the escape properties of run-and-tumble particles, a special kind of self-propelled particle characterized by a constant self-propulsion speed and random tumbling of heading direction, from a random potential that combines an asymmetric smooth component with spatially random perturbations (SRPs). The statistical reversal of escape direction is primarily governed by both self-propulsion speed and tumbling rate. SRPs tend to enhance the escape probability over the higher barrier relative to the base smooth potential in most cases and remarkably reduce the peak of the first passage time distributions in both escape directions, resulting in long tails. Specifically, we find that the logarithm of mean first passage time shows a linear dependence on the intensity and correlation length of SRPs. However, in contrast to the significant influence on the escape process, the SRPs have a weak effect on the overall shape of the probability density function except for some small-scale fluctuations. Our results support the oriented transportation and sorting of active particles with disordered substrates.