Natural Inflation with a periodic non-minimal coupling
Ricardo Z. Ferreira, Alessio Notari, Guillem Simeon
2018
Journal of Cosmology and Astroparticle Physics
Natural inflation is an attractive model for primordial inflation, since the potential for the inflaton is of the pseudo Nambu-Goldstone form, V(ϕ)=Λ^4 [1+cos (ϕ/f)], and so is protected against radiative corrections. Successful inflation can be achieved if f ≳ few M_P and Λ∼ m_GUT where Λ can be seen as the strong coupling scale of a given non-abelian gauge group. However, the latest observational constraints put natural inflation in some tension with data. We show here that a non-minimal
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... ing to gravity γ^2(ϕ) R, that respects the symmetry ϕ→ϕ+2 π f and has a simple form, proportional to the potential, can improve the agreement with cosmological data. Moreover, in certain cases, satisfactory agreement with the Planck 2018 TT, TE, EE and low P data can be achieved even for a periodicity scale of approximately M_p.
doi:10.1088/1475-7516/2018/11/021
fatcat:7gqiizin4vd2xecay4dqjgru7m