Superdiffusive, heterogeneous, and collective particle motion near the fluid-solid transition in athermal disordered materials

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.