Year: 2017
Type: article
Abstract: We show an analogy at high curvature between a f ( R ) = R + aR n − 1 + bR 2 theory and the α-Attractors. We calculate the expressions of the parameters a , b and n as functions of α and the predictions of the model f ( R ) = R + aR n − 1 + bR 2 on the scalar spectral index n s and the tensor-to-scalar ratio r . We find that the power law correction R n − 1 allows for a production of gravitational waves enhanced with respect to the one in the Starobinsky model, while maintaining a viable prediction on n s . We numerically reconstruct the full α-Attractors class of models testing the goodness of our high-energy approximation f ( R ) = R + aR n − 1 + bR 2 . Moreover, we also investigate the case of a single power law f ( R ) = γ R 2 − δ theory, with γ and δ free parameters. We calculate analytically the predictions of this model on the scalar spectral index n s and the tensor-to-scalar ratio r and the values of δ which are allowed from the current observational results. We find that −0.015 < δ < 0.016, confirming once again the excellent agreement between the Starobinsky model and observation.
Authors: T. Miranda, J. C. Fabris, O. F. Piattella
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2737544268