Elastic models of the glass transition applied to a liquid with density anomalies

TL;DR

This study tests elastic models of the glass transition in a system with water-like density anomalies, finding correlations with elastic properties but questioning the landscape interpretation.

Contribution

It demonstrates the applicability of elastic models to a new system with density anomalies and challenges the landscape-based interpretation of these models.

Findings

Clear correlation between relaxation time and elastic properties.

Plateau shear modulus not related to energy landscape features.

Supports elastic models but questions landscape interpretation.

Abstract

Elastic models of the glass transition relate the relaxation dynamics and the elastic properties of structural glasses. They are based on the assumption that the relaxation dynamics occurs through activated events in the energy landscape whose energy scale is set by the elasticity of the material. Here we investigate whether such elastic models describe the relaxation dynamics of systems of particles interacting via a purely repulsive harmonic potential, focusing on a volume fraction and temperature range that is characterized by entropy--driven water--like density anomalies. We do find clear correlations between relaxation time and diffusivity on the one hand, and plateau shear modulus and Debye--Waller factor on the other, thus supporting the validity of elastic models of the glass transition. However, we also show that the plateau shear modulus is not related to the features of the underlying energy landscape of the system, at variance with recent results for power--law potentials. This challenges the common potential energy landscape interpretation of elastic models.