Green-Kubo approach to the average swim speed in active Brownian systems

TL;DR

This paper introduces an exact Green-Kubo formula to compute the average swim speed in active Brownian systems, linking nonequilibrium averages to equilibrium correlations, validated through simulations.

Contribution

It presents a novel Green-Kubo approach for calculating the average swim speed in active matter, bridging equilibrium correlations with nonequilibrium properties.

Findings

Derived an exact formula relating swim speed to force autocorrelations.

Validated analytical results with Brownian dynamics simulations.

Provided a new tool for coarse-grained modeling of active matter.

Abstract

We develop an exact Green-Kubo formula relating nonequilibrium averages in systems of interacting active Brownian particles to equilibrium time-correlation functions. The method is applied to calculate the density-dependent average swim speed, which is a key quantity entering coarse grained theories of active matter. The average swim speed is determined by integrating the equilibrium autocorrelation function of the interaction force acting on a tagged particle. Analytical results are validated using Brownian dynamics simulations.