Comment on "Universal effect of excitation dispersion on the heat capacity and gapped states in fluids"

TL;DR

This paper critically examines recent claims of a universal relation linking heat capacity and excitation dispersions in liquids, questioning the generality of the previous findings.

Contribution

It provides a critical analysis of the validity of the proposed universal relation in the context of liquid thermodynamics.

Findings

Challenges the universality of the proposed relation

Highlights limitations in previous experimental data

Suggests conditions where the relation may not hold

Abstract

We discuss the validity of recent results in [Phys. Rev. Lett. 125, 125501 (2020)] on an universal relation between the heat capacity and dispersions of collective excitations in liquids.