Fractional attractors in light of the latest ACT observations

2025/04/03 by Christian Dioguardi, Antonio J. Iovino, Dioguardi, Christian +3 · 1 voice · 52 citations
Engineering · Physics and Astronomy · #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 #astro-ph.CO #gr-qc #hep-ph

paper · pdf · doi:10.48550/arxiv.2504.02809

openalex publication_date 2025/04/03 · arxiv published 2025/04/03 · arxiv updated 2025/06/19 · 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.

Cited by

• Exponential plateaus and inflation in metric-affine gravity
• Curvaton-assisted hilltop inflation
• Single-field D-type inflation in the minimal supergravity in light of Planck-ACT-SPT data
• Natural inflation in Palatini F(R)
• Quintessential Inflation in Light of ACT DR6
• Fibre Inflation Meets Quintessence: Implications of Perturbative Stabilisation
• Constraining non-minimally coupled squared-Quartic Hilltop Inflation in light of ACT observations
• k-inflation: Non-separable case meets ACT measurements
• Symmetry-Protected α-Attractor Hybrid Inflation in Supergravity and Constraints from ACT DR6 and DESI DR2
• The Harrison-Zeldovich attractor: From Planck to ACT
• Validation of NANOGrav 15-year data and ACT data by modified inflation in entropic cosmology
• GUT-Scale Smooth Hybrid Inflation with a Stabilized Modulus in Light of ACT and SPT Data
• Swampland Conjectures through ACT Observations: Observational Signatures of Radiative-Corrected Inflation
• The implications of inflation for the last ACT
• Updating GUT-Scale Pole Higgs Inflation After ACT
• Radiative-Corrected Higgs Inflation in Light of the Latest ACT Observations
• ACT Constraints on Marginally Deformed Starobinsky Inflation
• Quantum-Corrected ϕ⁴ Inflation in Light of ACT Observations
• Power-law F(R) Gravity as Deformations to Starobinsky Inflation in View of ACT
• Heavy Field Effects on Inflationary Models in Light of ACT Data
• String Corrected Scalar Field Inflation Compatible with the ACT Data
• Deformations of Starobinsky Inflation in No-Scale SU(5) and SO(10) GUTs
• ACT inflation and its influence on reheating era in Einstein-Gauss-Bonnet gravity
• Inflationary Models with Gauss-Bonnet Coupling in Light of ACT Observations
• Inflation in F(R) gravity models revisited after ACT
• Viability of generalized α-inflation from Planck, ACT, and DESI Data
• Confronting Inflation and Reheating with Observations: Improved Predictions Beyond Slow-Roll
• Reconciling Fractional Power Potential and EGB Gravity in the light of ACT
• ACT Implications for Hilltop Inflation
• Confronting Mukhanov Parametrization of Inflationary Equation-of-State with ACT-DR6
• ACT-Inspired Kaehler-Based Inflationary Attractors
• Observational constraints on inflationary models with non-minimally derivative coupling by ACT
• What new physics can we extract from inflation using the ACT DR6 and DESI DR2 Observations?
• Inflationary attractors and radiative corrections in light of ACT data
• Starobinsky like inflation and EGB Gravity in the light of ACT
• Improved Predictions on Higgs-Starobinsky Inflation and Reheating with ACT DR6 and Primordial Gravitational Waves
• Keeping the relation between the Starobinsky model and no-scale supergravity ACTive
• Kinetically Modified Palatini Inflation Meets ACT Data
• Higgs-like inflation under ACTivated mass
• Reconciling Higgs Inflation with ACT Observations through Reheating
• Minimal Plateau Inflation in light of ACT DR6 Observations
• Are single-field models of inflation and PBHs production ruled out by ACT observations?
• Viability of post-inflationary freeze-in with precision cosmology
• Constraining Reheating Temperature, Inflaton-SM Coupling and Dark Matter Mass in Light of ACT DR6 Observations
• Curvature corrections to Starobinsky inflation can explain the ACT results
• Approximate reconstruction of inflationary potential with ACT observations
• ACT-ing on inflation: Implications of non Bunch-Davies initial condition and reheating on single-field slow roll models
• Reheating ACTs on Starobinsky and Higgs inflation
• Refined Predictions for Starobinsky Inflation and Post-inflationary Constraints in Light of ACT
• Increase of n_s in regularized pole inflation & Einstein-Cartan gravity
• Non-minimal coupling in light of ACT
• Independent connection in ACTion during inflation

Discussions

• #NewPaper by our theorists Christian Dioguardi (Tallinn U. Tech. and NICPB, Tallinn) and Antonio Racioppi(NICPB, Tallinn) in collaboration with Antonio J. Iovino(New York U., Abu Dhabi and Munster U., [bsky, 1 points, 1 comments]

Related

• Gravitational Foundations and Exact Solutions in n-Dimensional Fractional Cosmology
• Representations of the fractional d'Alembertian and initial conditions in fractional dynamics
• Fractional space-like branes
• Fractional relativity
• Bound states in the continuum of fractional Schrödinger equation in the Earth's gravitational field and their effects in the presence of a minimal length: applications to distinguish ultralight particles