Anomalous Elasticity in Classical Glass-formers

TL;DR

This paper investigates how screening effects alter the elastic response in classical glass-formers, revealing deviations from classical elasticity due to plastic responses and emergent dipole sources.

Contribution

It introduces a new measure to quantify deviations from classical elasticity and demonstrates screening effects in classical glass-formers with different interparticle forces.

Findings

Elastic response can be strongly screened in classical glass-formers.

Deviations from classical elasticity depend on energy lost to plastic responses.

Screening effects are consistent across different interaction potentials.

Abstract

Amorphous solids under mechanical strains are prone to plastic responses. Recent work showed that in amorphous granular system these plastic events, that are typically quadrupolar in nature, can screen the elastic response. When the density of the quadrupoles is high, the gradients of the quadrupole field act as emergent dipole sources, leading to qualitative changes in the mechanical response, as seen for example in the displacement field. In this paper we examine the effect of screening in classical glass formers. These are made of point particles that interact via binary forces. Both inverse power law forces and Lennard-Jones interactions are examined, and it is shown that in both cases the elastic response can be strongly screened, in agreement with the novel theory. The degree of deviation from classical elasticity theory is parameterized by a proposed new measure that is shown to have a functional dependence of on the amount of energy lost to plastic responses.