Direct numerical analysis of dynamic facilitation in glass-forming liquids

TL;DR

This paper introduces a computational method to analyze how dynamic facilitation influences relaxation timescales and lengthscales in glass-forming liquids at low temperatures, revealing temperature-dependent behaviors.

Contribution

It provides a novel, assumption-free computational approach to quantify dynamic facilitation effects in glass-forming liquids across temperatures.

Findings

Dynamic facilitation varies strongly with temperature.

Relaxation events spread subdiffusively with a temperature-dependent exponent.

Temperature evolution significantly contributes to increased structural relaxation time.

Abstract

We propose a computational strategy to quantify the temperature evolution of the timescales and lengthscales over which dynamic facilitation affects the relaxation dynamics of glass-forming liquids at low temperatures, that requires no assumption about the nature of the dynamics. In two glass models, we find that dynamic facilitation depends strongly on temperature, leading to a subdiffusive spreading of relaxation events which we characterize using a temperature-dependent dynamic exponent. We also establish that this temperature evolution represents a major contribution to the increase of the structural relaxation time.