Phenomenological modeling of the motility of self-propelled microorganisms

TL;DR

This paper introduces a new stochastic model for microorganism motility that better matches experimental data than previous Gaussian noise-based models, advancing understanding of active matter dynamics.

Contribution

It proposes a novel stochastic model for microorganism movement that surpasses Gaussian noise assumptions and aligns well with experimental observations.

Findings

Experimental data contradict Gaussian white noise models.

The new model accurately reproduces velocity distributions.

The model shows good agreement with velocity autocorrelation data.

Abstract

The motility of microorganisms in liquid media is an important issue in active matter and it is not yet fully understood. Previous theoretical approaches dealing with the microscopic description of microbial movement have modeled the propelling force exerted by the organism as a Gaussian white noise term in the equation of motion. We present experimental results for ciliates of the genus Colpidium, which do not agree with the Gaussian white noise hypothesis. We propose a new stochastic model that goes beyond such assumption and displays good agreement with the experimental statistics of motion, such as velocity distribution and velocity autocorrelation.