Structure of marginally jammed polydisperse packings of frictionless spheres

TL;DR

This paper develops a model for the structure of marginally jammed polydisperse sphere packings, accurately predicting the radial distribution function and relating packing parameters, with validation against simulations and experiments.

Contribution

It introduces an extended granocentric model that explicitly includes rattlers to describe jammed packings of polydisperse spheres.

Findings

Model predictions for g(r) match simulations and experiments.

Quantitative agreement enables structural characterization of jammed systems.

Relationship established between packing parameters and radial distribution function.

Abstract

We model the packing structure of a marginally jammed bulk ensemble of polydisperse spheres using an extended granocentric mode explicitly taking into account rattlers. This leads to a relation- ship between the characteristic parameters of the packing, such as the mean number of neighbors and the fraction of rattlers, and the radial distribution function g(r). We find excellent agreement between the model predictions for g(r) and packing simulations as well as experiments on jammed emulsion droplets. The observed quantitative agreement opens the path towards a full structural characterization of jammed particle systems for imaging and scattering experiments.