Non-Gaussian noise without memory in active matter

TL;DR

This paper demonstrates that non-Gaussian, memoryless noise in active particles can cause boundary accumulation and phase separation, highlighting a key role of non-Gaussianity in active matter behavior.

Contribution

It reveals that non-Gaussian, memoryless noise alone can induce collective phenomena like phase separation in active matter, without the need for persistent or memory effects.

Findings

Non-Gaussian noise causes boundary accumulation.

Non-Gaussian noise leads to effective attraction between particles.

Motility-induced phase separation can occur without memory effects.

Abstract

Modeling the dynamics of an individual active particle invariably involves an isotropic noisy self-propulsion component, in the form of run-and-tumble motion or variations around it. This nonequilibrium source of noise is neither white---there is persistence---nor Gaussian. While emerging collective behavior in active matter has hitherto been attributed to the persistent ingredient, we focus on the non-Gaussian ingredient of self-propulsion. We show that by itself, that is without invoking any memory effect, it is able to generate particle accumulation close to boundaries and effective attraction between otherwise repulsive particles, a mechanism which generically leads to motility-induced phase separation in active matter.