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arXiv · 2502.13008

More accurate slow-roll approximations for inflation in scalar-tensor theories

Ekaterina O. Pozdeeva·Maria A. Skugoreva·Alexey V. Toporensky·Sergey Yu. Vernov
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Abstract

We propose new versions of the slow-roll approximation for inflationary models with nonminimally coupled scalar fields. We derive more precise expressions for the standard slow-roll parameters as functions of the scalar field. To verify the accuracy of the proposed approximations, we consider inflationary models with the induced gravity term and the fourth-order monomial potential. For specific values of the model parameters, this model is the well-known Higgs-driven inflationary model. We investigate the inflationary dynamics in the Jordan frame and come to the conclusion that the proposed versions of the slow-roll approximation are not only more accurate at the end of inflation, but also give essentially more precise estimations for the tensor-to-scalar ratio $r$ and the amplitude of scalar perturbations $A_s$.

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BibTeXRIS

Ekaterina O. Pozdeeva, Maria A. Skugoreva, Alexey V. Toporensky, Sergey Yu. Vernov. 2025-02-18. More accurate slow-roll approximations for inflation in scalar-tensor theories. https://doi.org/10.1088/1475-7516%2F2025%2F05%2F081

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