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Related papers: Closing in on $\alpha$-attractors

200 papers

In the large extra dimensional braneworld inflation, Friedmann equation is modified to include a quadratic term in energy density with an additional parameter $\lambda$ called brane tension in addition to the usual linear term. The high…

General Relativity and Quantum Cosmology · Physics 2020-01-15 Mudassar Sabir , Waqas Ahmed , Yungui Gong , Yizhou Lu

Recently a broad class of superconformal inflationary models was found leading to a universal observational prediction $n_s=1-2/N$ and $r=12/N^2$. Here we generalize this class of models by introducing a parameter $\alpha$ inversely…

High Energy Physics - Theory · Physics 2015-06-17 Renata Kallosh , Andrei Linde , Diederik Roest

Motivated by $\alpha$-attractor models, in this paper we consider a Gauss-Bonnet inflation with E-model type of potential. We consider the Gauss-Bonnet coupling function to be the same as the E-model potential. In the small $\alpha$ limit…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-02 Kourosh Nozari , Narges Rashidi

We present the first Bayesian constraints on the single field inflationary reheating era obtained from Cosmic Microwave Background (CMB) data. After demonstrating that this epoch can be fully characterized by the so-called reheating…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Jerome Martin , Christophe Ringeval

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 a class of slow roll inflationary models in the light of the recent Cosmic Microwave Background constraints from Planck 2018, ACT DR6, DESI DR1, and BICEP/\textit{Keck} 2018. The combined dataset favors a higher value of the…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-08 Suvashis Maity

Inflation creates both scalar (density) and tensor (gravity wave) metric perturbations. We find that the tensor mode contribution to the CMB anisotropy on large-angular scales can only exceed that of the scalar mode in models where the…

Astrophysics · Physics 2009-09-15 R. L. Davis , H. M. Hodges , G. F. Smoot , P. J. Steinhardt , M. S. Turner

Reheating phase of inflationary Universe can be modeled by parameters $T_{\text{reh}}$, $\bar{w}_{\text{reh}}$ and $N_{\text{reh}}$, which can be constrained by the scalar spectral amplitude $A_{s}$ and the scalar spectral index $n_{s}$. On…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-22 Rajesh Goswami , Urjit A. Yajnik

We study the evolution of the Universe at early stages, we discuss also preheating in the framework of hybrid braneworld inflation by setting conditions on the coupling constants $\lambda $ and $g$\ for effective production of…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-17 K. El Bourakadi , M. Bousder , Z. Sakhi , M. Bennai

The simplest $\alpha$-attractor $T$ model is given by the potential $V=V_0\tanh^2(\lambda\phi/M_{pl})$. However its generalization to the class of models of the type $V = V_0 \tanh^p (\lambda \phi/M_{pl})$ is difficult to interpret as a…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-13 Gabriel German

The $\alpha$-attractor models are some of the most interesting models of inflation from the point of view of upcoming observations in cosmology and also attractive from the point of view of supergravity. We confront representative models of…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-02 Sukannya Bhattacharya , Koushik Dutta , Mayukh R. Gangopadhyay , Anshuman Maharana

In the recent paper by Mielczarek \emph{et al.} (JCAP {\bf 1007} (2010) 004) an idea of the method which can be used to put some constraint for the reheating phase was proposed. Another method of constraining the reheating temperature has…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-25 Jakub Mielczarek

We explore constraints on inflationary models employing data on large scale structure mainly from COBE temperature anisotropies and IRAS selected galaxy surveys, taking care not to apply linear perturbation theory to data in the non-linear…

Astrophysics · Physics 2009-12-30 R. K. Schaefer , Q. Shafi

The recent data from the Boomerang and MAXIMA-1 balloon flights have marked the beginning of the precision era of Cosmic Microwave Background anisotropy (CMB) measurements. We investigate the observational constraints from the current CMB…

Astrophysics · Physics 2009-10-31 William H. Kinney , Alessandro Melchiorri , Antonio Riotto

Observations of the temperature anisotropies in the Cosmic Microwave Background (CMB) radiation show that the models of inflation with the monomial potentials are inconsistent with the allowed $n_s-r$ bounds. However certain monomial…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-17 Richa Arya , Raghavan Rangarajan

Constraints to the parameters of inflation models are often derived assuming some plausible range for the number--e.g., $N_k=46$ to $N_k=60$--of $e$-folds of inflation that occurred between the time that our current observable Universe…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-08 Julian B. Munoz , Marc Kamionkowski

Reheating in inflationary cosmology is essential for understanding the early universe, influencing particle production, thermalization, and the primordial power spectrum. Crucial quantities defined during the reheating epoc, such as the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-16 Gabriel German

Recent analyses combining Atacama Cosmology Telescope (ACT) data with other cosmological datasets report a higher scalar spectral index $n_s$, creating tension with a wide range of inflationary models. Since a Gauss-Bonnet term with a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-03 Yigan Zhu , Qing Gao , Yungui Gong , Zhu Yi

In this paper, we discuss three modified single-field natural inflation models in detail, including Special generalized Natural Inflation model(SNI), Extended Natural Inflation model(ENI) and Natural Inflation inspired model(NII). We derive…

High Energy Physics - Phenomenology · Physics 2022-07-13 Hua Zhou , Qing Yu , Yu Pan , Ruiyu Zhou , Wei Cheng

A novel approach to quintessential inflation model building is studied, within the framework of $\alpha$-attractors, motivated by supergravity theories. Inflationary observables are in excellent agreement with the latest CMB observations,…

General Relativity and Quantum Cosmology · Physics 2017-06-23 Konstantinos Dimopoulos , Charlotte Owen