Scalar-tensor extension of Natural Inflation. (arXiv:2002.07625v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Simeon_G/0/1/0/all/0/1">Guillem Simeon</a>
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 $phi rightarrow phi + 2pi f$ 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.
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 $phi rightarrow phi + 2pi f$ 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.
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