Superdiffusive, heterogeneous, and collective particle motion near the jamming transition in athermal disordered materials

TL;DR

This study uses computer simulations to analyze particle dynamics near the jamming transition in athermal materials, revealing superdiffusive, heterogeneous, and collective behaviors with unique signatures at the microscopic level.

Contribution

It uncovers original microscopic signatures of the jamming transition, including non-monotonic behavior of dynamic heterogeneity and scale-free correlations in particle motion.

Findings

Superdiffusive and heterogeneous particle motion observed.

Non-monotonic behavior of characteristic scales across the transition.

Intermittent elastic and plastic dynamics with scale-free correlations.

Abstract

We use computer simulations to study the microscopic dynamics of an athermal assembly of soft particles near the fluid-to-solid, jamming transition. Borrowing tools developed to study dynamic heterogeneity near glass transitions, we discover a number of original signatures of the jamming transition at the particle scale. We observe superdiffusive, spatially heterogeneous, and collective particle motion over a characteristic scale which displays a surprising non-monotonic behavior across the transition. In the solid phase, the dynamics is an intermittent succession of elastic deformations and plastic relaxations, which are both characterized by scale-free spatial correlations and system size dependent dynamic susceptibilities. Our results show that dynamic heterogeneities in dense athermal systems and glass-formers are very different, and shed light on recent experimental reports of `anomalous' dynamical behavior near the jamming transition of granular and colloidal assemblies.