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

Claus Heussinger (1) , Ludovic Berthier (2) , Jean-Louis Barrat (1)

1 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures
2 LCVN - Laboratoire des colloïdes, verres et nanomatériaux

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.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Claus Heussinger, Ludovic Berthier, Jean-Louis Barrat. Superdiffusive, heterogeneous, and collective particle motion near the jamming transition in athermal disordered materials. EPL - Europhysics Letters, 2009, 86, pp.10001. ⟨10.1209/0295-5075/90/20005⟩. ⟨hal-00444459⟩