Growing spatial correlations of particle displacements in a simulated liquid on cooling toward the glass transition

TL;DR

This paper introduces a correlation function to measure spatial correlations of particle displacements in liquids, revealing that these correlations grow and become long-range as the system approaches the glass transition temperature in simulations.

Contribution

It defines a new correlation function for particle displacements and demonstrates its growth during cooling in simulated liquids approaching the glass transition.

Findings

Long-range spatial correlations emerge near the glass transition.

Correlations grow as temperature decreases toward the mode coupling critical point.

The correlation function relates to fluctuations in a bulk dynamical variable.

Abstract

We define a correlation function that quantifies the spatial correlation of single-particle displacements in liquids and amorphous materials. We show for an equilibrium liquid that this function is related to fluctuations in a bulk dynamical variable. We evaluate this function using computer simulations of an equilibrium glass-forming liquid, and show that long range spatial correlations of displacements emerge and grow on cooling toward the mode coupling critical temperature.