Non-perturbative gauge invariant scalar fluctuations of the metric in Higgs inflation from complex geometrical scalar-tensor theory of gravity
Abstract
In this letter we investigate gauge invariant scalar fluctuations of the metric in a non-perturbative formalism for a Higgs inflationary model recently introduced in the framework of a geometrical scalar-tensor theory of gravity. In this scenario the Higgs inflaton field has its origin in the Weyl scalar field of the background geometry. We found a nearly scale invariance of the power spectrum for linear scalar fluctuations of the metric. For certain parameters of the model we obtain values for the scalar spectral index ns and the scalar to tensor ratio r that fit well with the Planck 2018 results. Besides we show that in this model the trans-planckian problem can be avoided.
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