Active Jamming at Criticality

TL;DR

This paper investigates how activity and thermal fluctuations influence the critical behavior of jammed solids, revealing that near the jamming point, active forces and temperature effects can be described by a mean-field framework, emphasizing the role of amorphous structure.

Contribution

The study provides a combined numerical and analytical analysis of active, soft, frictionless spheres near jamming, demonstrating universal scaling laws and the mean-field nature of active and thermal effects.

Findings

Active forces and temperature effects near jamming follow universal scaling laws.

Mean-field description effectively captures active and thermal influences on jamming.

Amorphous structure plays a crucial role in the critical behavior of active matter systems.

Abstract

Jamming is ubiquitous in disordered systems, but the critical behavior of jammed solids subjected to active forces or thermal fluctuations remains elusive. In particular, while passive athermal jamming remains mean-field-like in two and three dimensions, diverse active matter systems exhibit anomalous scaling behavior in all physical dimensions. It is therefore natural to ask whether activity leads to anomalous scaling in jammed systems. Here, we use numerical and analytical methods to study systems of active, soft, frictionless spheres in two dimensions, and elucidate the universal scaling behavior that relates the excess coordination, active forces or temperature, and pressure close to the athermal jammed point. We show that active forces and thermal effects around the critical jammed state can again be captured by a mean-field picture, thus highlighting the distinct and crucial role of amorphous structure in active matter systems.