Dynamics of a rod in a random static environment: non-Gaussianity at large length scales

TL;DR

This study uses molecular dynamics simulations to explore how a single rod moves in a two-dimensional static disordered environment, revealing persistent non-Gaussian behavior at large length scales indicative of dynamic heterogeneity.

Contribution

It demonstrates that long rods exhibit non-Gaussian displacement distributions at large scales, highlighting complex heterogeneity in their motion within static disordered media.

Findings

Long rods show cage effects similar to supercooled liquids.

The non-Gaussian parameter remains large even at large length scales.

Dynamics are highly heterogeneous at scales 10-15 times the rod length.

Abstract

We present molecular dynamics simulations of the motion of a single rod in a two-dimensional random static array of disks. For long rods the mean-squared displacement of the center-of-mass shows a cage effect similar to that observed in supercooled liquids or dense colloidal systems. We have determined the time-dependence of the non-Gaussian parameter for different rod lengths. It is found that the long-time regime is strongly non-Gaussian even at length scales of the order of 10-15 times the rod length, thus showing the heterogeneity of the dynamics at such length scales.