http://arxiv.org/abs/2002.07625
We show that embedding Natural Inflation into a more general scalar-tensor theory, with non-minimal couplings to the Ricci scalar and the kinetic term, alleviates the current tension of Natural Inflation with observational data. The coupling functions respect the periodicity of the potential and the characteristic shift symmetry $\phi \rightarrow \phi + 2\pi f$ of the original Natural Inflation model, and vanish at the minimum of the potential. Furthermore, showing that the theory exhibits a rescaling symmetry in the regime where the coupling to the Ricci scalar is small, we obtain that the agreement with cosmological data can take place at an arbitrarily low periodicity scale $f$, solving the problem of super-Planckian periodicity scales needed in Natural Inflation.
G. Simeon
Wed, 19 Feb 20
13/62
Comments: 3 pages, 1 figure
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