Inflationary universe in fluid description

TL;DR

This paper explores a fluid-based model of inflationary cosmology, demonstrating compatibility with Planck data, reconstructing the equation of state, and showing how the universe can exit inflation gracefully.

Contribution

It introduces a fluid description of inflation that aligns with observational data and provides a method to reconstruct the EoS from spectral indices.

Findings

Fluid models compatible with Planck data

Reconstructed EoS from spectral indices

Demonstrated graceful exit from inflation

Abstract

We investigate a fluid description of inflationary cosmology. It is shown that the three observables of the inflationary universe: the spectral index of the curvature perturbations, the tensor-to-scalar ratio of the density perturbations, and the running of the spectral index, can be compatible with the Planck analysis. In addition, we reconstruct the equation of state (EoS) for a fluid from the spectral index of the curvature perturbations consistent with the Planck results. We explicitly demonstrate that the universe can gracefully exit from inflation in the reconstructed fluid models. Furthermore, we explore the singular inflation for a fluid model.