Jamming at zero temperature, zero friction, and finite applied shear stress

TL;DR

This study uses molecular dynamics simulations to explore the hysteretic jamming transition in frictionless spheres under shear stress, revealing a complex energy landscape and mixed transition characteristics.

Contribution

It demonstrates the hysteretic nature of jamming at zero temperature and friction, and introduces a simple model explaining the energy landscape effects.

Findings

Hysteresis in jamming depends on control parameters and protocol.

Transition shows mixed first-order and second-order features.

Hysteresis disappears with strong viscous forces or small shear stress.

Abstract

Via molecular dynamics simulations, we unveil the hysteretic nature of the jamming transition of soft repulsive frictionless spheres, as it occurs varying the volume fraction or the shear stress. In a given range of control parameters the system may be found both in a flowing and in an jammed state, depending on the preparation protocol. The hysteresis is due to an underlying energy landscape with many minima, as explained by a simple model, and disappears in the presence of strong viscous forces and in the small $\sigma$ limit. In this limit, structural quantities are continuous at the transition, while the asymptotic values of two time quantities such as the self-intermediate scattering function are discontinuous, giving to the jamming transition a mixed first-order second-order character close to that found at the glass transition of thermal systems.