# Noise and diffusion of a vibrated self-propelled granular particle

## TL;DR

This study investigates the motion of vibrated granular particles, demonstrating that despite their unique noise-propulsion relationship, their behavior aligns with the active Brownian particle model, supporting its use in predicting collective phenomena.

## Contribution

The paper provides experimental validation of the active Brownian particle model for vibrated granular particles, highlighting its applicability despite the particles' unique noise and propulsion relationship.

## Key findings

- Granular particles exhibit features predicted by the ABP model.
- The noise-propulsion relationship in granular media is unique but still fits the ABP framework.
- The analysis method can be applied to other systems for model validation.

## Abstract

Granular materials are an important physical realization of active matter. In vibration-fluidized granular matter, both diffusion and self-propulsion derive from the same collisional forcing, unlike many other active systems where there is a clean separation between the origin of single-particle mobility and the coupling to noise. Here we present experimental studies of single-particle motion in a vibrated granular monolayer, along with theoretical analysis that compares grain motion at short and long time scales to the assumptions and predictions, respectively, of the active Brownian particle (ABP) model. The results demonstrate that despite the unique relation between noise and propulsion, granular media do show the generic features predicted by the ABP model and indicate that this is a valid framework to predict collective phenomena. Additionally, our scheme of analysis for validating the inputs and outputs of the model can be applied to other granular and non-granular systems.