Are supercooled liquids Fickian yet non Gaussian?
Abstract
Comment on `Fickian Non-Gaussian Diffusion in Glass-Forming Liquids', by Rusciano et al., Phys. Rev. Lett. 128, 168001 (2022). In a recent Letter, Rusciano et al. examined the statistics of individual particles displacements in two-dimensional glass-formers and concluded that the corresponding probability distribution is non-Gaussian in a time regime where the mean-squared displacement is Fickian. Here, we clarify that the multiple length scales and time scales reported in this work have either been characterized before, or are not well-defined. This leads us to dispute the conclusions that glass-formers display Fickian non-Gaussian behaviour and that this analogy fruitfully addresses the central questions regarding the nature of dynamic heterogeneity in these systems.
Keywords
Cite
@article{arxiv.2210.07119,
title = {Are supercooled liquids Fickian yet non Gaussian?},
author = {Ludovic Berthier and Elijah Flenner and Grzegorz Szamel},
journal= {arXiv preprint arXiv:2210.07119},
year = {2023}
}
Comments
2 pages, no figure