Granular Matter: a wonderful world of clusters in far-from-equilibrium systems

TL;DR

This paper reviews the unique behaviors of non-equilibrium granular systems, highlighting cluster formation, phase transition phenomena, and anomalous transport properties across different packing densities.

Contribution

It provides a comprehensive overview of the diverse features and unexpected phenomena in granular matter systems far from equilibrium.

Findings

Clusters vary with packing density from gas-like to sintered materials.

Unusual slow relaxation and transport properties are observed.

Interplay between phase transitions and self-organized criticality is discussed.

Abstract

In this paper, we recall various features of non equilibrium granular systems. Clusters with specific properties are found depending on the packing density, going from loose (a granular gas) to sintered (though brittle) polycrystalline materials. The phase space available can be quite different. Unexpected features, with respect to standard or expected ones in classical fluids or solids, are observed, - like slow relaxation processes or anomalous electrical and thermoelectrical transport property dependences. The cases of various pile structures and the interplay between classical phase transitions and self-organized criticality for avalanches are also outlined.