Slow dynamics and precursors of the glass transition in granular fluids

TL;DR

This study uses simulations to explore how granular fluids approach a glass transition, revealing how increased energy dissipation shifts the transition and affects precursor signals, with implications for understanding slow dynamics.

Contribution

It provides new insights into the effects of inelasticity on glass transition signatures in granular fluids, aligning with recent theoretical predictions.

Findings

Relaxation times increase over several orders of magnitude near the transition.

Higher inelasticity shifts the glass transition to higher densities.

Long-time tails in velocity autocorrelation affect diffusion properties.

Abstract

We use event driven simulations to analyze glassy dynamics as a function of density and energy dissipation in a two-dimensional bidisperse granular fluid under stationary conditions. Clear signatures of a glass transition are identified, such as an increase of relaxation times over several orders of magnitude. As the inelasticity is increased, the glass transition is shifted to higher densities and the precursors of the transition become less and less pronounced -- in agreement with a recent mode-coupling theory. We analyze the long-time tails of the velocity autocorrelation and discuss its consequences for the nonexistence of the diffusion constant in two dimensions.