Inflationary Cosmology Leading to a Soft Type Singularity

TL;DR

This paper explores cosmological models with a generalized equation of state that lead to a soft type IV singularity, connecting early inflation and late acceleration within a unified framework, and compares theoretical predictions with Planck satellite observations.

Contribution

It introduces models with inhomogeneous equations of state that produce multiple type IV singularities, linking soft singularities to both inflation and late-time acceleration.

Findings

Models with two type IV singularities at different cosmic epochs.

Parameter ranges for equations of state leading to singular inflation.

Correlation between slow-roll parameters and Planck satellite data.

Abstract

A remarkable property of modern cosmology is that it allows for a special case of symmetry, consisting in the possibility of describing the early-time acceleration (inflation) and the late-time acceleration using the same theoretical framework. In this paper we consider various cosmological models corresponding to a generalized form for the equation of state for the fluid in a flat Friedmann -Robertson-Walker universe, emphasizing cases where the so-called type IV singular inflation is encountered in the future. This is a soft (non-crushing) kind of singularity. Parameter values for an inhomogeneous equation of state leading to singular inflation are obtained. We present models for which there are two type IV singularities, the first corresponding to the end of the inflationary era and the second to a late time event. We also study the correspondence between the theoretical slow-roll parameters leading to type IV singular inflation and the recent results observed by the Planck satellite.