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arXiv · 2307.02963

Palatini $F(R,X)$: a new framework for inflationary attractors

Christian Dioguardi·Antonio Racioppi
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Abstract

Palatini $F(R)$ gravity proved to be a powerful tool in order to realize asymptotically flat inflaton potentials. Unfortunately, it also inevitably implies higher-order inflaton kinetic terms in the Einstein frame that might jeopardize the evolution of the system out of the slow-roll regime. We prove that a $F(R+X)$ gravity, where $X$ is the inflaton kinetic term, solves the issue. Moreover, when $F$ is a quadratic function such a choice easily leads to a new class of inflationary attractors, fractional attractors, that generalizes the already well-known polynomial $\alpha$-attractors.

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Christian Dioguardi, Antonio Racioppi. 2023-07-06. Palatini $F(R,X)$: a new framework for inflationary attractors. https://doi.org/10.1016/j.dark.2024.101509

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