Field-Embedded Particles Driven by Active Flips

TL;DR

This paper investigates how active flips in spin-carrying particles within a fluctuating environment induce patterned order, phase transitions, and microphase separation, combining simulations and analytical methods.

Contribution

It introduces a minimal model showing that activity-driven spin dynamics can produce diverse ordered patterns and phase behaviors in noninteracting particles.

Findings

Patterned order emerges from activity and mediated interactions.

Phase transitions and microphase separation occur, forming various cluster arrangements.

Dynamical regimes include persistent growth of magnetization lumps.

Abstract

Systems of independent active particles embedded into a fluctuating environment are relevant to many areas of soft-matter science. We use a minimal model of noninteracting spin-carrying Brownian particles in a Gaussian field and show that activity-driven spin dynamics leads to patterned order. We find that the competition between mediated interactions and active noise alone can yield such diverse behaviors as phase transitions and microphase separation, from lamellar up to hexagonal ordering of clusters of opposite magnetization. These rest on complex multibody interactions. We find regimes of stationary patterns, but also dynamical regimes of relentless birth and growth of lumps of magnetization opposite to the surrounding one. Our approach combines Monte-Carlo simulations with analytical methods based on dynamical density functional approaches.