A reentrancy of motility-induced phase separation in overdamped active Brownian particles

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Yamamoto, Hiroya
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866909672371388416
author Yamamoto, Hiroya
author_facet Yamamoto, Hiroya
contents In a system of Self-Propelled Particles (SPPs), the combination of self-propulsion and excluded volume effects can result in a phase separation called Motility-Induced Phase Separation (MIPS). Previous studies reported that MIPS is one of the phenomena so-called "reentrant phase separation" ,i.e., MIPS is suppressed when the Péclet number $Pe$ (dimensionless self-propelled speed) is sufficiently large. We used a fundamental model of SPPs, i.e., overdamped Active Brownian Partcles (ABPs), to investigate the mechanism of the reentrancy of MIPS. We expect that elucidating the conditions under which MIPS occur is important, since MIPS is a phenomenon that can occur in a wide range of SPPs systems, and the potential applications of MIPS can also be wide range. Detailed investigation of particle motion revealed that a entire particle cluster deforms due to multiple slip deformation (known as plastic deformation in materials science). As $Pe$ increases, the frequency of occurrence of slip-lines increases, and the particle motion becomes fluid-like. Therefore, the shape of the cluster becomes unstable and the number of particles in the cluster decreases. Let $\bf{f}_{LA}$ be the local spatial average of the self-propelled force generated by the particles. The observation of the inhomogeneity in the magnitude and direction of $\bf{f}_{LA}$ shows that $\bf{f}_{LA}$ is large on the cluster surface and generally orients toward the cluster inside. We determined that $\bf{f}_{LA}$ generates stress on the cluster, and it causes the multiple slip deformation.
format Preprint
id arxiv_https___arxiv_org_abs_2507_01553
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A reentrancy of motility-induced phase separation in overdamped active Brownian particles
Yamamoto, Hiroya
Soft Condensed Matter
In a system of Self-Propelled Particles (SPPs), the combination of self-propulsion and excluded volume effects can result in a phase separation called Motility-Induced Phase Separation (MIPS). Previous studies reported that MIPS is one of the phenomena so-called "reentrant phase separation" ,i.e., MIPS is suppressed when the Péclet number $Pe$ (dimensionless self-propelled speed) is sufficiently large. We used a fundamental model of SPPs, i.e., overdamped Active Brownian Partcles (ABPs), to investigate the mechanism of the reentrancy of MIPS. We expect that elucidating the conditions under which MIPS occur is important, since MIPS is a phenomenon that can occur in a wide range of SPPs systems, and the potential applications of MIPS can also be wide range. Detailed investigation of particle motion revealed that a entire particle cluster deforms due to multiple slip deformation (known as plastic deformation in materials science). As $Pe$ increases, the frequency of occurrence of slip-lines increases, and the particle motion becomes fluid-like. Therefore, the shape of the cluster becomes unstable and the number of particles in the cluster decreases. Let $\bf{f}_{LA}$ be the local spatial average of the self-propelled force generated by the particles. The observation of the inhomogeneity in the magnitude and direction of $\bf{f}_{LA}$ shows that $\bf{f}_{LA}$ is large on the cluster surface and generally orients toward the cluster inside. We determined that $\bf{f}_{LA}$ generates stress on the cluster, and it causes the multiple slip deformation.
title A reentrancy of motility-induced phase separation in overdamped active Brownian particles
topic Soft Condensed Matter
url https://arxiv.org/abs/2507.01553