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Active particles driven by competing spatially dependent self-propulsion and external force

by Lorenzo Caprini, Umberto Marini Bettolo Marconi, René Wittmann , Hartmut Löwen

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Submission summary

Authors (as registered SciPost users): Lorenzo Caprini
Submission information
Preprint Link: scipost_202203_00001v3  (pdf)
Date accepted: 2022-08-08
Date submitted: 2022-07-31 22:52
Submitted by: Caprini, Lorenzo
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
Specialties:
  • Statistical and Soft Matter Physics
Approach: Theoretical

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. We thus show that the interplay of two relatively simple physical fields can be employed to generate complex emerging behavior.

Published as SciPost Phys. 13, 065 (2022)



Author comments upon resubmission

The reply to the referees is included in the pdf attached, which contains also the main text of the paper.

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