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Related papers: ACT Implications for Hilltop Inflation

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Recent measurements from the Atacama Cosmology Telescope (ACT), particularly when combined with DESI baryon acoustic oscillation data, have reported a scalar spectral index $n_s$ slightly higher than that inferred by {\it Planck}~2018,…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-18 Jureeporn Yuennan , Farruh Atamurotov , Phongpichit Channuie

We propose a new class of inflationary models in which inflation takes place while the inflaton is climbing up a potential hill due to a coupling to gravity. We study their attractor behavior, and investigate its relation with known…

High Energy Physics - Phenomenology · Physics 2017-08-30 Ryusuke Jinno , Kunio Kaneta

We analyze the latest cosmic microwave background (CMB) constraints on the scalar spectral index $n_s$ and tensor-to-scalar ratio $r$ from Planck 2018, BICEP/Keck 2018, the Atacama Cosmology Telescope Data Release 6 (ACT DR6), and the South…

High Energy Physics - Phenomenology · Physics 2025-10-22 John Ellis , Marcos A. G. Garcia , Keith A. Olive , Sarunas Verner

Recent observations from the Atacama Cosmology Telescope (ACT) indicate a moderate upward shift in the scalar spectral index $n_s$ compared to Planck $2018$, thereby placing tighter constraints on inflationary scenarios. Motivated by these…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-25 Li-Yang Chen , Rongrong Zha , Feng-Yi Zhang

In the era of Planck cosmology, the inflationary paradigm is best fitted toward the cosmological attractor scenarios, including the induced inflation, universal attractors, conformal attractors, and special attractors that are cataloged as…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-28 Chengjie Fu , Di Lu , Shao-Jiang Wang

Recent analyses that combine the latest data from the Atacama Cosmology Telescope (ACT) with cosmic microwave background observations by BICEP/Keck and Planck, together with the DESI baryon acoustic-baryonic-oscillation (BAO) measurements,…

High Energy Physics - Phenomenology · Physics 2025-05-07 Wen Yin

In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton-Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the ${\cal W}_{-1}$ branch of the Lambert function. Depending…

General Relativity and Quantum Cosmology · Physics 2018-05-15 Barun Kumar Pal

We investigate the observational viability of non-minimally coupled scalar-Einstein-Gauss-Bonnet (GB) gravity, during inflation and post-inflationary reheating dynamics, from the perspective of the latest ACT-DR6 combined with the Planck…

General Relativity and Quantum Cosmology · Physics 2025-10-08 Sergei D. Odintsov , Tanmoy Paul

The Atacama Cosmology Telescope (ACT) has recently released new measurements and constraints on inflationary observables. In this paper it is shown that a component of a dynamical affine connection, which is independent of the metric, can…

High Energy Physics - Phenomenology · Physics 2025-09-03 Alberto Salvio

We analyze the Starobinsky inflation model and the impact of curvature corrections, particularly a cubic $R^3$ term, to assess their behavior in light of the latest observational results from the Atacama Cosmology Telescope (ACT). With the…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-30 J. Bezerra-Sobrinho , L. G. Medeiros

One of the longstanding goals in the framework of inflation is the construction of tools that can be used to classify models in theory space. An idea that has been put forward in this context is to consider the energy dependent scaling…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-21 Monika Lynker , Rolf Schimmrigk

In this article, we examine the effects of anisotropy on a model of canonical warm inflation with the power-law potential. The results of this model are compared to Planck satellite observational data. Using a conventional local scalar…

General Relativity and Quantum Cosmology · Physics 2022-05-05 Zahra Ghadiri , Ali Aghamohammadi , Abdollah Refaei

Recent measurements from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT) have placed the strictest constraints on the primordial scalar perturbation spectrum, reporting a spectral index of $n_s\sim0.967-0.98$ at 95%…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Qing-Yang Wang

There are many single field inflationary models that are consistent with the recent Planck 2018 measurements of the spectral index $n_s$ and tensor-to-scalar ratio $r$. Despite good agreement with observational data some of these models…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Josh Hoffmann , David Sloan

In this work we assess the implications of the Atacama Cosmology Telescope DR6 measurements for two interacting dark radiation scenarios previously shown to mitigate the Hubble tension. The first model, Wess-Zumino dark radiation (WZDR),…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 William Cvetko , Melissa Joseph , Gustavo Marques-Tavares

We investigate the observational constraints on $\alpha$-attractor inflationary models and their post-inflationary reheating dynamics in light of the latest CMB data from ACT DR6 combined with Planck18, BICEP/$Keck$ 2018, and DESI…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-06 Md Riajul Haque , Sourav Pal , Debarun Paul

Hilltop inflation models are often described by potentials $V = V_{0}(1-{\phi^{n}\over m^{n}}+...)$. The omitted terms indicated by ellipsis do not affect inflation for $m \lesssim 1$, but the most popular models with $n =2$ and $4$ for $m…

High Energy Physics - Theory · Physics 2019-09-25 Renata Kallosh , Andrei Linde

The recent measurements from the Atacama Cosmology Telescope (ACT) favor a higher value of the scalar spectral index $n_s$ compared to the Planck data, challenging many well-established inflationary models. In this work, we investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-27 Zhi-Zhang Peng , Zu-Cheng Chen , Lang Liu

Accurate estimation of cosmological parameters from microwave background anisotropies requires high-accuracy understanding of the cosmological model. Normally, a power-law spectrum of density perturbations is assumed, in which case the…

Astrophysics · Physics 2009-10-30 Edmund J Copeland , Ian J Grivell , Andrew R Liddle

We investigate the impact of different choice of prior's range for the reheating epoch on cosmic inflation parameter inference in light of cosmic microwave background (CMB) anisotropy measurements from the {\em Planck} 2018 legacy release…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 Mario Ballardini