Equilibrium and non-equilibrium fluctuations in a glass-forming liquid

TL;DR

This study investigates local fluctuations in a glass-forming liquid through simulations, revealing similar behaviors in equilibrium and non-equilibrium states and weak temperature dependence of dynamic susceptibility.

Contribution

It provides a detailed comparison of fluctuations in equilibrium and aging regimes, showing their similarity and weak temperature dependence of susceptibility.

Findings

Fluctuation distributions are similar in equilibrium and aging regimes.

Integrated dynamic susceptibility shows weak temperature dependence.

Fluctuations are consistent across different timescales and regimes.

Abstract

Glass-forming liquids display strong fluctuations -- dynamical heterogeneities -- near their glass transition. By numerically simulating a binary Weeks-Chandler-Andersen liquid and varying both temperature and timescale, we investigate the probability distributions of two kinds of local fluctuations in the non-equilibrium (aging) regime and in the equilibrium regime; and find them to be very similar in the two regimes and across temperatures. We also observe that, when appropriately rescaled, the integrated dynamic susceptibility is very weakly dependent on temperature and very similar in both regimes.