Scaling theory for the jamming transition

TL;DR

This paper develops a scaling theory for the elastic energy near the jamming transition, predicting critical exponents and scaling behaviors verified by simulations, and offers new insights into the differing scalings of shear and bulk moduli.

Contribution

It introduces a comprehensive scaling ansatz for the jamming transition, deriving new exponents and relations, and connects the transition to emergent scale invariance and potential renormalization-group approaches.

Findings

Predicted new critical exponents and scaling relations.

Verified scaling collapses for energy, pressure, and shear stress.

Explained the different scaling behaviors of shear and bulk moduli.

Abstract

We propose a scaling ansatz for the elastic energy of a system near the critical jamming transition in terms of three relevant fields: the compressive strain $\Delta \phi$ relative to the critical jammed state, the shear strain $\epsilon$, and the inverse system size $1/N$. We also use $\Delta Z$, the number of contacts relative to the minimum required at jamming, as an underlying control parameter. Our scaling theory predicts new exponents, exponent equalities and scaling collapses for energy, pressure and shear stress that we verify with numerical simulations of jammed packings of soft spheres. It also yields new insight into why the shear and bulk moduli exhibit different scalings; the difference arises because the shear stress vanishes as $1/\sqrt{N}$ while the pressure approaches a constant in the thermodynamic limit. The success of the scaling ansatz implies that the jamming transition exhibits an emergent scale invariance, and that it should be possible to develop a renormalization-group theory for jamming.