Pattern Formation and Transport for Externally Driven Active Matter on Periodic Substrates

TL;DR

This paper studies how active particles driven through obstacles behave under different activity levels, revealing distinct dynamic phases and transport signatures that resemble driven solids or fluids.

Contribution

It introduces a detailed analysis of phase transitions and transport properties of active matter on periodic substrates across activity regimes.

Findings

High activity leads to phase-separated states with distinct transport phases.

Transport and velocity fluctuations correlate with phase transitions.

Low activity shows minimal change in transport with drive.

Abstract

We investigate the transport of interacting active run-and-tumble particles moving under an external drift force through a periodic array of obstacles for increasing drive amplitudes. For high activity where the system forms a motility induced phase separated state, there are several distinct dynamic phases including a low drive pinned cluster phase, an intermediate uniform fluid, and a higher drive stripe crystal state. The transitions between the phases are correlated with signatures in the transport curves, differential mobility, and power spectra of the velocity fluctuations. In contrast, in the low activity regime the transport curves and power spectra undergo little change as a function of drive. We argue that in the high activity limit, the behavior is similar to that of driven solids on periodic substrates, while in the low activity limit the system behaves like a driven fluid.