Comment on Singularity-free Cosmological Solutions with Non-rotating Perfect Fluids

TL;DR

This paper challenges a previous conjecture about non-rotating, non-singular perfect fluid cosmological models, providing a counterexample and clarifying the reasons for the conjecture's failure.

Contribution

It presents a counterexample to Raychaudhuri's conjecture, demonstrating that not all non-rotating, non-singular perfect fluid cosmologies belong to the Ruiz-Senovilla and Fernandez-Jambrina families.

Findings

Counterexample disproves Raychaudhuri's conjecture

Identifies flaw in the original argument

Expands understanding of possible cosmological models

Abstract

A conjecture stated by Raychaudhuri which claims that the only physical perfect fluid non-rotating non-singular cosmological models are comprised in the Ruiz-Senovilla and Fernandez-Jambrina families is shown to be incorrect. An explicit counterexample is provided and the failure of the argument leading to the result is explicitly pointed out.