Soft deformable self-propelled particles

TL;DR

This paper explores how deformable self-propelled particles exhibit collective behaviors such as alignment, clustering, and laning, influenced by interactions and noise, revealing new phenomena like reentrant fluidity and connecting to established models.

Contribution

It introduces the role of deformation in inducing alignment and demonstrates novel behaviors like laning and reentrant fluidity in self-propelled particle systems.

Findings

Deformation alone can induce velocity alignment.

Gaussian-core interactions lead to reentrant fluid behavior.

Laning observed for deformable particles with intermediate potentials.

Abstract

In this work we investigate the collective behavior of self-propelled particles that deform due to local pairwise interactions. We demonstrate that this deformation alone can induce alignment of the velocity vectors. The onset of collective motion is analyzed. Applying a Gaussian-core repulsion between the particles, we find a transition to disordered non-collective motion under compression. We here explain that this reflects the reentrant fluid behavior of the general Gaussian-core model now applied to a self-propelled system. Truncating the Gaussian potential can lead to cluster crystallization or more disordered cluster states. For intermediate values of the Gaussian-core potential we for the first time observe laning for deformable self-propelled particles. Finally, without the core potential, but including orientational noise, we connect our description to the Vicsek approach for self-propelled particles with nematic alignment interactions.