Comment on "Viscous cosmology in the Kasner metric"

TL;DR

This paper critiques previous work on viscous cosmology in Kasner metrics, demonstrating that entropy growth cannot be reconciled with thermodynamics and energy conditions in anisotropic Bianchi type I models, challenging earlier findings.

Contribution

It provides a critical analysis showing the incompatibility of entropy growth with thermodynamics and energy conditions in Kasner-type models, disputing prior results.

Findings

Entropy growth is incompatible with thermodynamics in Kasner models.

Previous claims of entropy increase in such models are challenged.

The analysis constrains the applicability of viscous cosmology in anisotropic universes.

Abstract

We show in this comment that in an anisotropic Bianchi type I model of the Kasner form, it is not possible to describe the growth of entropy, if we want to keep the thermodynamics together with the dominant energy conditions. This consequence disagrees with the results obtained by Brevik and Pettersen [Phys. Rev. D 56, 3322 (1997)].