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We investigate a standard minimally-coupled scalar-field inflationary scenario, which is based on a new potential, with suitably generalized plateau features, that leads to extra small tensor-to-scalar ratios. In particular, we consider a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-13 Gerasimos Kouniatalis , Emmanuel N. Saridakis

The most current observational data corroborate the Starobinsky model as one of the strongest candidates in the description of an inflationary regime. Motivated by such success, extensions of the Starobinsky model have been increasingly…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 G. Rodrigues-da-Silva , J. Bezerra-Sobrinho , L. G. Medeiros

The first inflationary model conceived was the one proposed by Starobinsky which includes an additional term quadratic in the Ricci-scalar R in the Einstein-Hilbert action. The model is now considered a target for several future cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-27 S. Santos da Costa , M. Benetti , R. M. P. Neves , F. A. Brito , R. Silva , J. S. Alcaniz

We consider the Starobinsky inflation with a set of higher order corrections parametrised by two real coefficients $\lambda_1, \lambda_2$. In the Einstein frame we have found a potential with the Starobinsky plateau, steep slope and…

High Energy Physics - Theory · Physics 2015-02-06 Michal Artymowski , Zygmunt Lalak , Marek Lewicki

We update the constraints on the power spectra of primordial curvature perturbation and tensor perturbation including Planck data 2015 (P15) and recently released BICEP2/Keck data (BK15), Baryon Acoustic Oscillation data and the Type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-15 Jun Li , Qing-Guo Huang

This paper presents the CMB angular power spectrum obtained using the \texttt{CAMB} code for three different models of inflation: the Starobinsky inflationary model, the generalized Starobinsky inflationary model, and the chaotic…

General Relativity and Quantum Cosmology · Physics 2024-10-23 Daniel Pozo , Lenin Calvache , Esteban Orozco , Vicente A. Arévalo , Clara Rojas

An extension of the Starobinsky model is proposed. Besides the usual Starobinsky Lagrangian, a term proportional to the derivative of the scalar curvature, $\nabla_{\mu}R\nabla^{\mu}R$, is considered. The analyzis is done in the Einstein…

General Relativity and Quantum Cosmology · Physics 2019-03-04 R. R. Cuzinatto , L. G. Medeiros , P. J. Pompeia

The Starobinsky model is one of the inflation models consistent with the result of CMB observation by the Planck satellite. We consider the dynamics of the Starobinsky inflation in the presence of another scalar field with a large…

High Energy Physics - Phenomenology · Physics 2016-05-25 Shinta Kasuya , Kanto Moritake

We propose a one-parametric extension of the Starobinsky $R+R^2$ model by adding the $(R+m^2\beta^2)^{3/2}$ term. The parameter $m$ is the inflaton mass, which is determined in the same way as in the Starobinsky model, and $\beta$ is a…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Ekaterina O. Pozdeeva , Sergey Yu. Vernov

We introduce a modification of the Starobinsky model in the form of an additional cubic Ricci scalar curvature term $\sim \alpha R^3$, scaled by a dimensionless parameter $\alpha$, with the resulting inflaton potential being the standard…

General Relativity and Quantum Cosmology · Physics 2025-09-23 Ioannis D. Gialamas , Theodoros Katsoulas , Kyriakos Tamvakis

We investigate a constraint on reheating followed by alpha-attractor-type inflation (the E-model and T-model) from an observation of the spectral index n_s. When the energy density of the universe is dominated by an energy component with…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-04 Yoshiki Ueno , Kazuhiro Yamamoto

The Starobinsky model, considered in the framework of the Palatini formalism, in contrast to the metric formulation, does not provide us with a model for inflation, due to the absence of a propagating scalar degree of freedom that can play…

General Relativity and Quantum Cosmology · Physics 2018-11-28 I. Antoniadis , A. Karam , A. Lykkas , K. Tamvakis

We show how to constrain inflationary models and reheating by using mixed constraints. In particular we study the physics of the reheating phase after inflation from observational constraints to the inflationary stage. We show that it is…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-26 Gabriel German , Juan Carlos Hidalgo , Ariadna Montiel

We investigate the implications of recent CMB observations for Higgs-Starobinsky inflationary models and their associated reheating dynamics, utilizing data from ACT DR6, Planck 2018, BICEP/Keck 2018, and DESI, collectively referred to as…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Md Riajul Haque , Sourav Pal , Debarun Paul

In the present work we study a warm inflationary model defined by a quasi-exponential inflaton potential and an inflaton decay rate proportional to the Hubble rate. The model is characterized by three free parameters. We compute the power…

General Relativity and Quantum Cosmology · Physics 2018-06-13 Nelson Videla , Grigoris Panotopoulos

We point out that the ability of some models of inflation, such as Higgs inflation and the universal attractor models, in reproducing the available data is due to their relation to the Starobinsky model of inflation. For large field values,…

High Energy Physics - Theory · Physics 2014-03-05 Alex Kehagias , Azadeh Moradinezhad Dizgah , Antonio Riotto

We provide the latest constraints on the power spectra of both scalar and tensor perturbations from the CMB data (including \textit{Planck}~2015, BICEP2 \& \textit{Keck Array} experiments) and the new BAO scales from SDSS-III BOSS…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-20 Qing-Guo Huang , Ke Wang , Sai Wang

We extend an alternative, phenomenological approach to inflation by means of an equation of state and a sound speed, both of them functions of the number of $e$-folds and four phenomenological parameters. This approach captures a number of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-10 Stefano Gariazzo , Olga Mena , Hector Ramirez , Lotfi Boubekeur

Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a higher value for the spectral index $n_s$. This places Starobinsky inflation at the edge of the $2\sigma$ constraints for a number…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Manuel Drees , Yong Xu

Inflation is part of the Standard Model of the Universe supported by CMB and large scale structure LSS datasets. This review presents new developments of inflation in three main chapters. (I): The effective theory of inflation a la…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-13 D. Boyanovsky , C. Destri , H. J. de Vega , N. G. Sanchez