Fractional attractors in light of the latest ACT observations

2025/04/03 by Christian Dioguardi, Antonio J. Iovino, Dioguardi, Christian +3 · 28 citations
Engineering · #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Phenomenology (hep-ph) #Magnetic Bearings and Levitation Dynamics

paper · pdf · doi:10.48550/arxiv.2504.02809

openalex publication_date 2025/04/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

In light of the latest results from ACT observations we review a class of potentials labeled as fractional attractors, that can originate from Palatini gravity. We show that, for certain choices of the scalar potential V(ϕ), the fractional attractors predict both a spectral index n_s and a tensor-to-scalar ratio r that fall within the 1σ region of the combined ACT+Planck data for a wide range of parameters. We also provide a numerical fit for the parameter space of this models in the case of a simple quadratic and quartic fractional potential.

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