Testing α -attractor quintessential inflation against CMB and low-redshift data

Journal Article · 12 November 2024 · Physics of the Dark Universe

DOI: https://doi.org/10.1016/j.dark.2024.101713 · OSTI ID:2479979

Giarè, William  ^[1]; Di Valentino, Eleonora  ^[1]; Linder, Eric V.  ^[2]; Specogna, Enrico ^[1]

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1. Univ. of Sheffield (United Kingdom)
2. Univ. of California, Berkeley, CA (United States)

Due to universality and attractor properties, α-attractor quintessential inflation establishes direct relations between inflationary observables such as the scalar tilt n_s and the tensor-to-scalar ratio r, and late-time dark energy equation of state parameters w₀ and w_a. In this work, we examine three different physically motivated regimes, considering complete freedom in the parameter α, models inspired by supergravity where α takes on values up to α = 7/3, and Starobinsky inflation (α = 1). We investigate the consistency and constraints imposed by Cosmic Microwave Background measurements from the Planck satellite, B-mode polarization data from the BICEP/Keck collaboration, and low-redshift observations. Additionally, we consider small-scale CMB measurements released by the Atacama Cosmology Telescope, which give results approaching the Harrison– Zel’dovich spectrum (n_s ≈ 1). Here α-attractors lead to an improved fit over $$\Lambda$$CDM. For the large-scale CMB measurements, α ≳ 2 models can provide equally good fits as $$\Lambda$$CDM

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2479979
• Journal Information: Physics of the Dark Universe, Journal Name: Physics of the Dark Universe Vol. 46; ISSN 2212-6864
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English