Inflationary universe in fluid description

Understand

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.