Dynamics of active particles with translational and rotational inertia

TL;DR

This paper introduces an inertial active Ornstein-Uhlenbeck particle model that incorporates translational and rotational inertia, aligning with inertial active Brownian particle dynamics to better understand active matter systems.

Contribution

It develops a comprehensive inertial AOUP model including mass and moment of inertia, bridging the gap with inertial ABP models for active matter.

Findings

Inertial AOUP captures key features of inertial ABP models.

Model predicts similar dynamics for small/moderate rotational inertia.

Provides steady-state properties for inertial active particles.

Abstract

Inertial effects affecting both the translational and rotational dynamics are inherent to a broad range of active systems at the macroscopic scale. Thus, there is a pivotal need for proper models in the framework of active matter to correctly reproduce experimental results, hopefully achieving theoretical insights. For this purpose, we propose an inertial version of the active Ornstein-Uhlenbeck particle (AOUP) model accounting for particle mass (translational inertia) as well as its moment of inertia (rotational inertia) and derive the full expression for its steady-state properties. The inertial AOUP dynamics introduced in this paper is designed to capture the basic features of the well-established inertial active Brownian particle (ABP) model, i.e., the persistence time of the active motion and the long-time diffusion coefficient. For a small or moderate rotational inertia, these two models predict similar dynamics at all timescales and, in general, our inertial AOUP model consistently yields the same trend upon changing the moment of inertia for various dynamical correlation functions.