Propulsion dispersion mediated ordering transition in active particles

TL;DR

This paper demonstrates that variations in propulsion strength among active particles can induce new collective phases with combined spatial and orientational order, expanding understanding of active matter behavior.

Contribution

It introduces the concept that propulsion dispersion can lead to novel ordered phases in active particles, with analytical characterization of phase boundaries.

Findings

Identification of three distinct phases: disordered, partially ordered, fully ordered.

Formation of ring-like structures in the partially ordered phase.

Analytical determination of phase boundaries using a harmonic potential.

Abstract

We show that dispersion in propulsion strength qualitatively alters collective behavior of active multi-particle systems interacting via short-range attractive potential, giving rise to novel ordered phases that combine spatial and orientational ordering. Considering a binary mixture of active Brownian particles with two distinct self-propulsion strengths, we find that, the interplay between interaction range, self-propulsion strengths and the relative numbers of the particles with different propulsion strengths can lead to three different phases, namely, a disordered one, and two ordered ones with partial and complete spatial and orientational ordering. The partially ordered phase is characterized by formation of a ring-like assembly of the slower particles while the faster particles diffuse randomly. Two concentric rings, comprising faster and slower particles, form in the fully ordered phase. Using the example of a truncated harmonic potential, we analytically characterize the phase boundaries and identify the associated order parameters. Our results demonstrate that propulsion dispersion provides a robust and novel route to collective ordering in attractive active matter.