Generalized Brans-Dicke inflation with a quartic potential

Abstract

Within the framework of Brans-Dicke gravity, we investigate inflation with the quartic potential, $\lambda {\phi }^4/4$, in the presence of generalized Brans-Dicke parameter ${\omega }_{\mathrm{GBD}}(\phi )$. We obtain the inflationary observables containing the scalar spectral index, the tensor-to-scalar ratio, the running of the scalar spectral index and the equilateral non-Gaussianity parameter in terms of general form of the potential $U(\phi )$ and ${\omega }_{\mathrm{GBD}}(\phi )$. For the quartic potential, our results show that the predictions of the model are in well agreement with the Planck 2015 data for the generalized Brans-Dicke parameters ${\omega }_{\mathrm{GBD}}(\phi )={\omega }_0{\phi }^n$ and ${\omega }_0{e}^{b\phi }$. This is in contrast with both the Einstein and standard Brans-Dicke gravity, in which the result of quartic potential is disfavored by the Planck data.

13 pages, 6 figures

References in corpus (1)

• Primordial Non-Gaussianities from Inflation Models