On the generalised Chaplygin gas: worse than a big rip or quieter than a sudden singularity?

TL;DR

This paper investigates various singularities in generalized Chaplygin gas models, revealing that such singularities can occur independently of phantom behavior and depend on initial conditions like brane tension.

Contribution

It demonstrates the potential for different singularities in generalized Chaplygin gas models and clarifies their origins beyond phantom characteristics.

Findings

Singularities can occur without phantom nature.

A large initial brane tension can introduce an infrared cutoff in the past.

Different types of future and past singularities are possible in these models.

Abstract

Although it has been believed that the models with generalised Chaplygin gas do not contain singularities, in a previous work we have studied how a big freeze could take place in some kinds of phantom generalised Chaplygin gas. In the present work, we study some types of generalised Chaplygin gas in order to show how different sorts of singularities could appears in such models, in the future or in the past. We point out that: (i) singularities may not be originated from the phantom nature of the fluid, and (ii) if initially the tension of the brane in a brane-world Chaplygin model is large enough then an infrared cut off appears in the past.