Future Directions for Active Matter on Ordered Substrates

TL;DR

This paper reviews how active matter systems interacting with ordered substrates exhibit novel nonequilibrium phenomena, highlighting future research directions in active phases, commensuration effects, and related physical behaviors.

Contribution

It provides an overview of the current understanding and outlines future research directions for active matter on periodic substrates, emphasizing new phenomena and phases.

Findings

Identification of new active phases and commensuration effects.

Proposal of future research directions including active solitons and active Mott phases.

Discussion of potential phenomena like active time crystals and active tribology.

Abstract

Active matter is a term encompassing particle-based assemblies with some form of self-propulsion, including certain biological systems as well as synthetic systems such as artificial colloidal swimmers, all of which can exhibit a remarkable variety of new kinds of nonequilibrium phenomena. A wealth of non-active condensed matter systems can be described in terms of a collection of particles coupled to periodic substrates, leading to the emergence of commensurate-incommensurate effects, Mott phases, tribology effects, and pattern formation. It is natural to ask how such phases are modified when the system is active. Here we provide an overview and future directions for studying individual and collectively interacting active matter particles coupled to periodic substrates, where new types of commensuration effects, directional locking, and active phases can occur. Further directions for exploration include locking effects, the realization of active solitons or active defects in incommensurate phases, active Mott phases, active artificial spin ice, active doping transitions, active floating phases, active surface physics, active matter time crystals, and active tribology.