Phase behavior of active Brownian disks, spheres, and dumbbells

TL;DR

This study provides high-precision phase diagrams for active Brownian particles, examining how shape and dimensionality affect phase separation, and compares different particle geometries including disks, spheres, and dumbbells.

Contribution

It introduces a precise simulation method for phase boundaries and explores the effects of particle shape and propulsion correlation on phase behavior.

Findings

Active spheres and dumbbells exhibit distinct phase separation regions.

Correlation in propulsion influences the phase diagram of dumbbells.

Dimensionality impacts the coexistence densities in active particle systems.

Abstract

In this paper we provide high precision estimates of the phase diagram of active Brownian particles. We extract coexisting densities from simulations of phase separated states in an elongated box (slab geometry) which minimizes finite-size effects and allows for precise determination of points on the binodal lines. Using this method, we study the influence of both shape and dimensionality on the two-phase region. Active spheres and dumbbells of active particles are compared to the known phase diagram of active Brownian disks. In the case of dimers, both correlated and uncorrelated propulsion of the two beads are studied. The influence of correlation is discussed through a simple mapping.