Reduced description method in the kinetic theory of Brownian motion with active fluctuations

TL;DR

This paper introduces a microscopic approach to the kinetic theory of active particle systems with dissipative and potential interactions, incorporating active fluctuations and deriving kinetic equations for weakly interacting systems.

Contribution

It generalizes the Bogolyubov--Peletminsky reduced description method to active particles, enabling the derivation of kinetic equations with active fluctuations and non-linear friction.

Findings

Derived kinetic equations match known results in special cases.

Active fluctuations cause head-tail asymmetry and self-propulsion.

The approach applies to 2D and 3D systems with weak interactions.

Abstract

We develop a microscopic approach to the kinetic theory of many-particle systems with dissipative and potential interactions in presence of active fluctuations. The approach is based on a generalization of Bogolyubov--Peletminsky reduced description method applied to the systems of many active particles. It is shown that the microscopic approach developed allows to construct the kinetic theory of two- and three-dimensional systems of active particles in presence of non-linear friction (dissipative interaction) and an external random field with active fluctuations. The kinetic equations for these systems in case of a weak interaction between the particles (both potential and dissipative) and low-intensity active fluctuations are obtained. We demonstrate particular cases in which the derived kinetic equations have solutions that match the results known in the literature. It is shown that the display of the head-tail asymmetry and self-propelling even in the case of a linear friction, is one of the consequences of the local nature of the active fluctuations.