Perspective: Nonequilibrium glassy dynamics in dense systems of active particles

TL;DR

This paper reviews recent experimental and theoretical advances in understanding how activity influences glassy dynamics in dense active matter systems, highlighting minimal models and future research directions.

Contribution

It provides a comprehensive overview of experimental findings and introduces minimal models to study the interplay of activity and crowding in dense systems.

Findings

Active systems exhibit classic glassy signatures and novel phenomena at high density.

Minimal models reveal how activity competes with interactions and crowding.

Future research directions include developing more complex models and theoretical frameworks.

Abstract

Despite the diversity of materials designated as active matter, virtually all active systems undergo a form of dynamic arrest when crowding and activity compete, reminiscent of the dynamic arrest observed in colloidal and molecular fluids undergoing a glass transition. We present a short perspective on recent and ongoing efforts to understand how activity competes with other physical interactions in dense systems. We first review recent experimental work on active materials that uncovered both classic signatures of glassy dynamics and intriguing novel phenomena at large density. We introduce a minimal model of self-propelled particles where the competition between interparticle interactions, crowding, and self-propulsion can be studied in great detail. We discuss more complex models that include some additional, material-specific ingredients. We end with some general perspectives on dense active materials, suggesting directions for future research, in particular for theoretical work.