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In this paper, we study inflation with {\alpha}-attractor potential in the RS braneworlds where high energy corrections to the Friedmann equation facilitate slow roll. In this scenario, we numerically investigate the inflationary parameters…

General Relativity and Quantum Cosmology · Physics 2019-05-22 Nur Jaman , Kairat Myrzakulov

We consider a brane world inflationary model in which inflation is driven by dynamics of a self-interacting scalar field living in the five-dimensional bulk. The scalar field is non-minimally coupled to matter fields on the brane and acts…

General Relativity and Quantum Cosmology · Physics 2020-11-11 Y. Bisabr , F. Ahmadi

In this work we shall investigate the phenomenological implications of the constant-roll condition on a $k$-Inflation theory of gravity. The latter theories are particularly promising, since these remained robust to the results of GW170817,…

General Relativity and Quantum Cosmology · Physics 2020-01-29 S. D. Odintsov , V. K. Oikonomou

We consider the simplest extension to the Starobinsky model, by allowing an extra scalar field to help drive inflation. We perform our analysis in the Einstein frame and calculate the power spectra at the end of inflation to second order in…

High Energy Physics - Theory · Physics 2015-10-21 Carsten van de Bruck , Laura Elena Paduraru

We explore the homogeneous background dynamics and the evolution of generated perturbations of cosmological inflation that is driven by multiple scalar fields interacting with a perfect fluid.Then we apply the method to warm inflation…

General Relativity and Quantum Cosmology · Physics 2018-04-04 Yang-Yang Wang , Jian-Yang Zhu , Xiao-Min Zhang

We consider inflation in the system containing a Ricci scalar squared term and a canonical scalar field with quadratic mass term. In the Einstein frame this model takes the form of a two-field inflation model with a curved field space, and…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-01 Taro Mori , Kazunori Kohri , Jonathan White

We examine cosmological inflation in a broad family of scalar-tensor models characterized by scalar-dependent non minimal kinetic couplings and Gauss-Bonnet terms. Using a slow roll-approximation, we compute in detail theoretical…

High Energy Physics - Theory · Physics 2026-05-21 A. Belhaj , H. Es-Sobbahi , M. Oualaid , E. Torrente-Lujan

We compare the standard single scalar field inflationary predictions with those of an inflationary phase driven by a tachyon field. A slow-roll formalism is defined for tachyon inflation, and we derive the spectra of scalar and tensor…

High Energy Physics - Theory · Physics 2008-11-26 D. A. Steer , F. Vernizzi

We consider non-canonical generalizations of two classes of simple single-field inflation models. First, we study the non-canonical version of "ultra-slow roll" inflation, which is a class of inflation models for which quantum modes do not…

Astrophysics · Physics 2009-11-13 Konstantinos Tzirakis , William H. Kinney

We calculate the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$ in a class of recently proposed two-field no-scale inflationary models in supergravity. We show that, in order to obtain correct predictions, it is crucial to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Sébastien Renaux-Petel , Krzysztof Turzynski

We investigate slow-roll inflation in a multi-field random Gaussian landscape. The landscape is assumed to be small-field, with a correlation length much smaller than the Planck scale. Inflation then typically occurs in small patches of the…

High Energy Physics - Theory · Physics 2018-02-13 Ali Masoumi , Alexander Vilenkin , Masaki Yamada

We discuss the coupled Einstein-Klein-Gordon equations for a complex scalar field with and without a quartic self-interaction in a zero curvature Friedman-Lema\^{\i}tre Universe. The complex scalar field, as well as the metric, is…

General Relativity and Quantum Cosmology · Physics 2011-04-15 D. Scialom

In the context of scalar-tensor theories of gravity we compute the third-order corrected spectral indices in the slow-roll approximation. The calculation is carried out by employing the Green's function method for scalar and tensor…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Alexandros Karam , Thomas Pappas , Kyriakos Tamvakis

We investigate slow-roll inflation within the framework of Kaniadakis and dual Kaniadakis cosmology, where the usual entropy formalism is generalized through a deformation parameter $\kappa$. By deriving the modified Friedmann equations and…

General Relativity and Quantum Cosmology · Physics 2026-05-19 Leila Liravi , Ahmad Sheykhi

In this paper we study canonical scalar field models with a varying second slow-roll parameter, that allow transitions between constant-roll eras. In the models with two constant-roll eras it is possible to avoid fine-tunings in the initial…

General Relativity and Quantum Cosmology · Physics 2017-07-26 S. D. Odintsov , V. K. Oikonomou

Higgs inflation with a Gauss-Bonnet term is studied in the Einstein frame. Our model features two coupling functions, $\Omega^2(\phi)$ and $\omega(\phi)$, coupled to the Ricci scalar and Gauss-Bonnet combinations. We found a special…

General Relativity and Quantum Cosmology · Physics 2024-03-26 Seoktae Koh , Seong Chan Park , Gansukh Tumurtushaa

We discuss and clarify the validity of effective single field theories of inflation obtained by integrating out heavy degrees of freedom in the regime where adiabatic perturbations propagate with a suppressed speed of sound. We show by…

High Energy Physics - Theory · Physics 2012-12-17 Ana Achucarro , Vicente Atal , Sebastian Cespedes , Jinn-Ouk Gong , Gonzalo A. Palma , Subodh P. Patil

We initially consider two simple situations where inflationary slow roll parameters are large and modes no longer freeze out shortly after exiting the horizon, treating both cases analytically. We then consider applications to transient…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-03 Jessica L. Cook , Lawrence M. Krauss

Solid inflation is a cosmological model where inflation is driven by fields which enter the Lagrangian in the same way as body coordinates of a solid matter enter the equation of state, spontaneously breaking spatial translational and…

General Relativity and Quantum Cosmology · Physics 2019-03-18 Peter Mészáros

One of the firm predictions of the single-scalar field inflationary cosmology is the consistency relation between the scalar and tensor perturbations. It has been argued that such a relation, if observationally verified, would offer strong…

Astrophysics · Physics 2010-02-09 Damien Gredat , S. Shankaranarayanan