Active particles driven by competing spatially dependent self-propulsion and external force
Abstract
We investigate how the competing presence of a nonuniform motility landscape and an external confining field affects the properties of active particles. We employ the active Ornstein-Uhlenbeck particle (AOUP) model with a periodic swim velocity profile to derive analytical approximations for the steady-state probability distribution of position and velocity, encompassing both the Unified Colored Noise Approximation and the theory of potential-free active particles with spatially dependent swim velocity recently developed. We test the theory by confining an active particle in a harmonic trap, which gives rise to interesting properties, such as a transition from a unimodal to a bimodal (and, eventually multimodal) spatial density, induced by decreasing the spatial period of the self propulsion. Correspondingly, the velocity distribution shows pronounced deviations from the Gaussian shape, even displaying a bimodal profile in the high-motility regions. Our results can be confirmed by real-space experiments on active colloidal Janus particles in external fields.
Cite
@article{arxiv.2203.00603,
title = {Active particles driven by competing spatially dependent self-propulsion and external force},
author = {Lorenzo Caprini and Umberto Marini Bettolo Marconi and René Wittmann and Hartmut Löwen},
journal= {arXiv preprint arXiv:2203.00603},
year = {2022}
}