Avalanches and Dynamical Correlations in supercooled liquids

TL;DR

This study uncovers how microscopic particle motions in supercooled liquids form clusters and avalanches, revealing similarities with granular media and advancing understanding of dynamical heterogeneity in glassy systems.

Contribution

It identifies the pattern of dynamical relaxation and the role of soft regions in supercooled liquids, linking microscopic dynamics to macroscopic heterogeneity.

Findings

Particle motion forms clusters called cage jumps.

Clusters aggregate into avalanches over larger timescales.

Dynamical heterogeneity resembles that in granular media.

Abstract

We identify the pattern of microscopic dynamical relaxation for a two dimensional glass forming liquid. On short timescales, bursts of irreversible particle motion, called cage jumps, aggregate into clusters. On larger time scales, clusters aggregate both spatially and temporally into avalanches. This propagation of mobility, or dynamic facilitation, takes place along the soft regions of the systems, which have been identified by computing isoconfigurational Debye-Waller maps. Our results characterize the way in which dynamical heterogeneity evolves in moderately supercooled liquids and reveal that it is astonishingly similar to the one found for dense glassy granular media.