Exponential distributions of collective flow-event properties in viscous liquid dynamics

TL;DR

This study reveals that in supercooled liquids, the distributions of collective flow-event properties such as energy, pressure, and shear stress become exponential at low temperatures, with the event size distribution governing these properties.

Contribution

It demonstrates how the distribution of event sizes controls the statistics of collective flow-event properties in viscous liquids, linking single-particle displacements to collective behavior.

Findings

Distributions of energy, pressure, and shear stress become exponential at low temperatures.

Event size distribution follows from exponential tails in single-particle displacement distributions.

The event size distribution influences the collective flow-event properties.

Abstract

We study the statistics of flow events in the inherent dynamics in supercooled two- and three-dimensional binary Lennard-Jones liquids. Distributions of changes of the collective quantities energy, pressure and shear stress become exponential at low temperatures, as does that of the event "size" $S\equiv\sum {d_i}^2$. We show how the $S$-distribution controls the others, while itself following from exponential tails in the distributions of (1) single particle displacements $d$, involving a Lindemann-like length $d_L$ and (2) the number of active particles (with $d>d_L$).