In this paper we establish formulae for the inflationary slow-roll parameters , η and ζ as functions of the Ricci scalar R for f(R) theories of gravity. As examples, we present the analytic and numerical solutions of , η and ζ as functions of the number of e-folds N in two important instances: for the Starobinsky model and for a f(R) reconstruction of the α-Attractors. The highlight of our proposal is to rewrite the slow-roll parameters in terms of f(R), which allows to find directly ns, r, αs and fequilNL as functions of R itself. We obtain that both models indicate a small contribution to the non-Gaussianity parameters, which are in good agreement with current observational constraints.

Generic slow-roll and non-gaussianity parameters in () theories

PIATTELLA O;
2019-01-01

Abstract

In this paper we establish formulae for the inflationary slow-roll parameters , η and ζ as functions of the Ricci scalar R for f(R) theories of gravity. As examples, we present the analytic and numerical solutions of , η and ζ as functions of the number of e-folds N in two important instances: for the Starobinsky model and for a f(R) reconstruction of the α-Attractors. The highlight of our proposal is to rewrite the slow-roll parameters in terms of f(R), which allows to find directly ns, r, αs and fequilNL as functions of R itself. We obtain that both models indicate a small contribution to the non-Gaussianity parameters, which are in good agreement with current observational constraints.
2019
https://doi.org/10.1088/1475-7516/2019/05/028
Tays, Miranda; Celia, Escamilla-Rivera; Piattella, O; Júlio C., Fabris
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2125251
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