Testing Adam-Gibbs relationship in tapped Granular Packings

TL;DR

This study investigates whether the Adam-Gibbs relationship, known in supercooled liquids, also applies to granular packings, revealing a close relationship between granular materials and ideal hard sphere models.

Contribution

It experimentally demonstrates that the Adam-Gibbs relationship holds in granular packings, linking thermodynamic parameters with relaxation dynamics across different friction levels.

Findings

Adam-Gibbs relationship is generally followed in granular packings.

Thermodynamic parameters like effective temperature and configurational entropy are quantified.

Granular systems show a close relationship with ideal frictionless hard sphere models.

Abstract

Disordered granular packings share many similarities with supercooled liquids, particu-larly in the rapid increase of structural relaxation time within a narrow range of temperature or packing fraction. However, it is unclear whether the dynamics of granular materials align with those of their corresponding thermal hard sphere liquids, and the particular influence of friction of a granular system remains largely unexplored. Here, we experimentally study the slow relaxation and the steady state of monodisperse granular sphere packings with X-ray tomography. We first quantify the thermodynamic parameters under the Edwards' ensemble, (i.e., effective temperature and configurational entropy), of granular spheres with varying friction, and measure their characteristic relaxation time during compaction processes. We then demonstrate a unified picture of the relaxation process in granular systems in which the Adam-Gibbs (AG) relationship is generally followed. These results clarify the close relation-ship between granular materials and the ideal frictionless hard sphere model.