Transport of a heated granular gas in a washboard potential

TL;DR

This paper investigates how a one-dimensional granular gas driven by stochastic forces moves in a washboard potential, revealing different transport regimes and the impact of elastic and inelastic collisions on mobility and diffusion.

Contribution

It provides a detailed numerical analysis of the effects of elastic and inelastic collisions on granular gas transport in a washboard potential, highlighting differences between overdamped and underdamped regimes.

Findings

Overdamped regime shows similarities with non-interacting particles.

Underdamped regime exhibits complex behaviors due to inelastic collisions.

Inelastic collisions can unexpectedly enhance diffusion.

Abstract

We study numerically the motion of a one dimensional array of Brownian particles in a washboard potential, driven by an external stochastic force and interacting via short range repulsive forces. In particular, we investigate the role of instantaneous elastic and inelastic collisions on the system dynamics and transport. The system displays a locked regime, where particles may move only via activated processes and a running regime where particles drift along the direction of the applied field. By tuning the value of the friction parameter controlling the Brownian motion we explore both the overdamped dynamics and the underdamped dynamics. In the two regimes we considered the mobility and the diffusivity of the system as functions of the tilt and other relevant control parameters such as, coefficient of restitution, particle size and total number of particles. We find that, while in the overdamped regime, the results for the interacting systems present similarities with the known non-interacting case, in the underdamped regime, the inelastic collisions determine a rich variety of behaviors among which is an unexpected enhancement of the inelastic diffusion.