Inflationary universe from perfect fluid and $F(R)$ gravity and its comparison with observational data

Understand

We investigate the descriptions for the observables of inflationary models, in particular, the spectral index of curvature perturbations, the tensor-to-scalar ratio, and the running of the spectral index, in the framework of perfect fluid models and $F(R)$ gravity theories through the reconstruction methods.

• Furthermore, the perfect fluid and $F(R)$ gravity descriptions of inflation are compared with the recent cosmological observations such as the Planck satellite and BICEP2 experiment.
• It is demonstrated with explicit examples that perfect fluid may lead to the inflationary universe consistent with the Planck data.
• It is also shown that several $F(R)$ gravity models, especially, a power-law model gives the best fit values compatible with the spectral index and tensor-to-scalar ratio within the allowed ranges suggested by the Planck and BICEP2 results.