Pair correlation of dilute Active Brownian Particles: from low activity dipolar correction to high activity algebraic depletion wings

TL;DR

This paper investigates the pair correlation functions of dilute Active Brownian Particles, revealing winged depletion zones and algebraic decay at high activity, supported by simulations, analytical models, and experiments.

Contribution

It introduces a comprehensive analysis of depletion wings in active particles, combining analytical, numerical, and experimental approaches to characterize their structure and decay regimes.

Findings

Depletion wings are observed in pair correlations of active particles.

High activity leads to self-similar, algebraically decaying depletion wings.

Experimental evidence confirms the simulation and theoretical predictions.

Abstract

We study the pair correlation of Active Brownian Particles at low density using numerical simulations and analytical calculations. We observe a winged pair correlation: while particles accumulate in front of an active particle as expected, the depletion wake consists of two depletion wings. In the limit of soft particles, we obtain a closed equation for the pair correlation, allowing us to characterize the depletion wings. In particular, we unveil two regimes at high activity where the wings adopt a self-similar profile and decay algebraically. We also perform experiments of self-propelled Janus particles and indeed observe the depletion wings.