Crystallization and flow in active patch systems

TL;DR

This paper investigates how spatially patterned activity influences the structure and dynamics of active particle systems, revealing similarities to temperature gradients and unique behaviors in asymmetric patches.

Contribution

It introduces a simulation framework for active patches in Janus particle systems and analyzes the resulting stationary states, highlighting novel effects of spatial activity patterns.

Findings

Spatial inhomogeneity in activity mimics temperature gradients.

Asymmetric patches produce distinct stationary states.

Active patches influence particle crystallization and flow patterns.

Abstract

Based upon recent experiments in which Janus particles are made into active swimmers by illuminating them with laser light, we explore the effect of applying a light pattern on the sample, thereby creating activity inducing zones or active patches. We simulate a system of interacting Brownian diffusers that become active swimmers when moving inside an active patch and analyze the structure and dynamics of the ensuing stationary state. We find that, in some respects, the effect of spatially inhomogeneous activity is qualitatively similar to a temperature gradient. For asymmetric patches, however, this analogy breaks down because the ensuing stationary state is specific to partial active motion.