Quasi-Rip and Pseudo-Rip Universes Induced by the Fluid Inhomogeneous Equation of State

TL;DR

This paper explores models of dark energy that lead to Quasi-Rip and Pseudo-Rip cosmologies, analyzing conditions under which these scenarios occur and drawing parallels with viscous cosmology theories.

Contribution

It introduces specific fluid inhomogeneous equations of state that produce Quasi-Rip and Pseudo-Rip universes, detailing the conditions for their emergence.

Findings

Conditions for Quasi-Rip and Pseudo-Rip depend on equation of state parameters.

In Quasi-Rip, w transitions from less than -1 to greater than -1.

In Pseudo-Rip, the Hubble parameter approaches a constant value.

Abstract

We investigate specific models for a dark energy universe leading to Quasi-Rip and Pseudo-Rip cosmologies. In the Quasi-Rip model the equation of state parameter w is less than -1 in the first stage, but becomes larger than -1 in the second stage. In the Pseudo-Rip model the Hubble parameter tends to a constant value in the remote future, although w is always less than -1. Conditions for the appearance of the Quasi-Rip and the Pseudo-Rip in terms of the parameters in the equation of state are determined. Analogies with the theory of viscous cosmology are discussed.