Self-alignment and anti-self-alignment suppress motility-induced phase separation in active systems

Fuente: arXiv
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Main Authors: Musacchio, Marco, Antonov, Alexander P., Löwen, Hartmut, Caprini, Lorenzo
Format: Preprint
Published: 2025
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author Musacchio, Marco
Antonov, Alexander P.
Löwen, Hartmut
Caprini, Lorenzo
author_facet Musacchio, Marco
Antonov, Alexander P.
Löwen, Hartmut
Caprini, Lorenzo
contents In this article, we investigate the impact of self-alignment and anti-self-alignment on collective phenomena in dense active matter. These mechanisms correspond to effective torques that align or anti-align a particles orientation with its velocity, as observed in active granular systems. In the context of motility-induced phase separation (MIPS) - a non-equilibrium coexistence between a dense clustered phase and a dilute homogeneous phase - both self- and anti-self-alignment are found to suppress clustering. Specifically, increasing self-alignment strength first leads to flocking within the dense cluster, and eventually to the emergence of a homogeneous flocking phase. In contrast, anti-self-alignment induces a freezing phenomenon, progressively reducing particle speed until MIPS is suppressed and a homogeneous phase is recovered. These results are supported by scaling arguments and are amenable to experimental verification in high-density active granular systems exhibiting self- or anti-self-alignment.
format Preprint
id arxiv_https___arxiv_org_abs_2504_04644
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Self-alignment and anti-self-alignment suppress motility-induced phase separation in active systems
Musacchio, Marco
Antonov, Alexander P.
Löwen, Hartmut
Caprini, Lorenzo
Soft Condensed Matter
Statistical Mechanics
In this article, we investigate the impact of self-alignment and anti-self-alignment on collective phenomena in dense active matter. These mechanisms correspond to effective torques that align or anti-align a particles orientation with its velocity, as observed in active granular systems. In the context of motility-induced phase separation (MIPS) - a non-equilibrium coexistence between a dense clustered phase and a dilute homogeneous phase - both self- and anti-self-alignment are found to suppress clustering. Specifically, increasing self-alignment strength first leads to flocking within the dense cluster, and eventually to the emergence of a homogeneous flocking phase. In contrast, anti-self-alignment induces a freezing phenomenon, progressively reducing particle speed until MIPS is suppressed and a homogeneous phase is recovered. These results are supported by scaling arguments and are amenable to experimental verification in high-density active granular systems exhibiting self- or anti-self-alignment.
title Self-alignment and anti-self-alignment suppress motility-induced phase separation in active systems
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2504.04644