Collective motion of energy depot active disks

TL;DR

This study investigates how active disks with energy depots self-organize into collective motion, revealing flocking behavior, band formation, and phase transitions influenced by activity levels in a two-dimensional setting.

Contribution

It introduces a model of active disks with energy depots and demonstrates flocking, band formation, and phase transitions similar to the Vicsek model, highlighting the role of activity in collective behavior.

Findings

Flocking transition with band formation observed.

Large density bands diminish with increased activity.

Homogeneous polar state emerges at high activity.

Abstract

In the present work we have studied collectives of active disks with an energy depot, moving in the two-dimensional plane and interacting via excluded volume. The energy depot accounts for the extraction of energy taking place at the level of each particle in order to perform self-propulsion, included in an underdampled Langevin dynamics. We show that this model undergoes a flocking transition, exhibiting some of the key features of the Vicsek model, namely, band formation and giant number fluctuations. Large density bands disappear as the activity is further increased, eventually reaching a homogeneous polar state. We unravel an effective alignment interaction at the level of two-particle collisions that can be controlled by activity and gives rise to flocking at large scales.