Rattler-induced aging dynamics in jammed granular systems

TL;DR

This paper investigates the aging dynamics in jammed granular systems, revealing that rattler particles dominate kinetic energy and influence relaxation behavior during the jamming transition.

Contribution

It uncovers the role of rattler particles in the aging process and characterizes the kinetic energy relaxation with a double power-law decay.

Findings

Rattler particles dominate kinetic energy in jammed states.

Jamming transition is not marked by zero kinetic energy.

Kinetic energy relaxation follows a double power-law decay.

Abstract

Granular materials jam when developing a network of contact forces able to resist the applied stresses. Through numerical simulations of the dynamics of the jamming process, we show that the jamming transition does not occur when the kinetic energy vanishes. Rather, as the system jams, the kinetic energy becomes dominated by rattlers particles, that scatter withing their cages. The relaxation of the kinetic energy in the jammed configuration exhibits a double power-law decay, which we interpret in terms of the interplay between backbone and rattlers particles.