2013/12/31 by Karina E. Avila, Horacio E. Castillo, Andrea Fiege +2
Engineering · Materials Science · Physics and Astronomy · #Condensed matter physics #Dynamic structure factor #Exponent #Geometry #Granular flow and fluidized beds #Inelastic neutron scattering #Inelastic scattering #Material Dynamics and Properties #Mathematical physics #Physics #Quantum mechanics #Scaling #Scaling law #Scattering #Theoretical and Computational Physics #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevlett.113.025701
published as Phys. Rev. Lett. 113, 025701 (2014) · 5 pages, 6 figures
arxiv created 2014/04/17 · openalex publication_date 2014/07/10 · arxiv updated 2014/07/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Large-scale simulations of two-dimensional bidisperse granular fluids allow us to determine spatial correlations of slow particles via the four-point structure factor S4(q,t). Both cases, elastic (ϵ=1) and inelastic (ϵ<1) collisions, are studied. As the fluid approaches structural arrest, i.e., for packing fractions in the range 0.6\ensuremath≤\ensuremathφ\ensuremath≤0.805, scaling is shown to hold: S4(q,t)/\ensuremathχ4(t)=s(q\ensuremathξ(t)). Both the dynamic susceptibility \ensuremathχ4(\ensuremathτ_\ensuremathα) and the dynamic correlation length \ensuremathξ(\ensuremathτ_\ensuremathα) evaluated at the \ensuremathα relaxation time \ensuremathτ_\ensuremathα can be fitted to a power law divergence at a critical packing fraction. The measured \ensuremathξ(\ensuremathτ_\ensuremathα) widely exceeds the largest one previously observed for three-dimensional (3d) hard sphere fluids. The number of particles in a slow cluster and the correlation length are related by a robust power law, \ensuremathχ4(\ensuremathτ_\ensuremathα)\ensuremath≈\ensuremathξ^d\ensuremath-p(\ensuremathτ_\ensuremathα), with an exponent d\ensuremath-p\ensuremath≈1.6. This scaling is remarkably independent of ϵ, even though the strength of the dynamical heterogeneity at constant volume fraction depends strongly on ϵ.