Dynamical diversity and metastability in a hindered granular column near jamming

TL;DR

This paper models a hindered granular column near jamming, revealing a rich phase diagram with four dynamical phases and analyzing metastability, jamming times, and deviations from equilibrium in different phases.

Contribution

It introduces a non-equilibrium stochastic model capturing the complex dynamical phases and metastability in hindered granular columns near jamming, highlighting the glassy phase behavior.

Findings

Four dynamical phases identified: ballistic, activated, logarithmic, glassy.

Metastable states and jamming times vary across phases.

Glassy phase shows intermittency and deviation from Edwards' flatness.

Abstract

Granular media jam into a panoply of metastable states. The way in which these states are achieved depends on the nature of local and global constraints on grains; here we investigate this issue by means of a non-equilibrium stochastic model of a hindered granular column near its jamming limit. Grains feel the constraints of grains above and below them differently, depending on their position. A rich phase diagram with four dynamical phases (ballistic, activated, logarithmic and glassy) is revealed. The statistics of the jamming time and of the metastable states reached as attractors of the zero-temperature dynamics is investigated in each of these phases. Of particular interest is the glassy phase, where intermittency and a strong deviation from Edwards' flatness are manifest.