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arXiv · 2503.16324

Natural inflation in Palatini $F(R,X)$

N. Bostan·R. H. Dejrah·C. Dioguardi·A. Racioppi
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Abstract

In the context of Palatini gravity, $F(R+X)$ models, with X the inflaton kinetic term, are characterized by the appealing property of generating asymptotically flat inflaton potentials, exactly like the more commonly studied Palatini $F(R)$ models, but without the complication of non-canonical inflaton kinetic terms in the Einstein frame. In this paper, we study the case of a Jordan frame potential which is positive and bounded, specifically, natural inflation. We compute the CMB observables and show that for a wide class of $F(R + X)$ theories, including the quadratic one, natural inflation is still viable.

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N. Bostan, R. H. Dejrah, C. Dioguardi, A. Racioppi. 2025-03-20. Natural inflation in Palatini $F(R,X)$. https://doi.org/10.1088/1475-7516%2F2025%2F07%2F082

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