Athermal Jamming vs Thermalized Glassiness in Sheared Frictionless Particles

TL;DR

This study uses simulations to explore how frictionless particles behave under shear across different thermal and athermal conditions, revealing distinct jamming and glass transition behaviors.

Contribution

It demonstrates that athermal jamming and thermalized glassiness are governed by separate critical points, depending on the ratio T/γ̇, and introduces a framework connecting these regimes.

Findings

Athermal jamming occurs at a well-defined packing fraction φ_J.

Thermalized glass transition may occur at a lower packing fraction φ_G.

Athermal and thermal transitions are controlled by different critical points.

Abstract

Numerical simulations of soft-core frictionless disks in two dimensions are carried out to study behavior of a simple liquid as a function of thermal temperature $T$, packing fraction $\phi$, and uniform applied shear strain rate $\dot\gamma$. Inferring the hard-core limit from our soft-core results, we find that it depends on the two parameters $\phi$ and $T/\dot\gamma$. $T/\dot\gamma\to 0$ defines the athermal limit in which a shear driven jamming transition occurs at a well defined $\phi_J$. $T/\dot\gamma\to\infty$ defines the thermalized limit where an equilibrium glass transition may take place at a $\phi_G$. This conclusion argues that athermal jamming and equilibrium glassy behavior are not controlled by the same critical point. Preliminary results suggest $\phi_G <\phi_J$.