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arXiv · 1810.12884

Nonminimal Coleman--Weinberg Inflation with an $R^2$ term

Alexandros Karam·Thomas Pappas·Kyriakos Tamvakis
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Abstract

We extend the Coleman--Weinberg inflationary model where a scalar field $\phi$ is non-minimally coupled to gravity with the addition of the $R^2$ term. We express the theory in terms of two scalar fields and going to the Einstein frame we employ the Gildener--Weinberg formalism, compute the one-loop effective potential and essentially reduce the problem to the case of single-field inflation. It turns out that there is only one free parameter, namely, the mixing angle between the scalars. For a wide range of this angle, we compute the inflationary observables which are in agreement with the latest experimental bounds. The effect of the $R^2$ term is that it lowers the value of the tensor-to-scalar ratio $r$.

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Alexandros Karam, Thomas Pappas, Kyriakos Tamvakis. 2018-10-30. Nonminimal Coleman--Weinberg Inflation with an $R^2$ term. https://doi.org/10.1088/1475-7516%2F2019%2F02%2F006

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