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We consider inflation with a constant rate of rolling in which a complex scalar field plays the role of inflaton during the inflationary epoch. We implement the inflationary analysis for an accredited angular speed $\dot{\theta}$ which…

General Relativity and Quantum Cosmology · Physics 2024-05-16 Ramón Herrera , Mehdi Shokri , Jafar Sadeghi

The primary purpose of this study is to investigate the constant-roll inflationary scenario with anisotropic conditions concerning the Einstein-aether Scalar-tensor cosmology in noncommutative phase space. We first introduce an…

General Relativity and Quantum Cosmology · Physics 2023-02-14 Antonio Pasqua , Saeed Noori Gashti

I describe a general approach to characterizing cosmological inflation outside the standard slow-roll approximation, based on the Hamilton-Jacobi formulation of scalar field dynamics. The basic idea is to view the equation of state of the…

High Energy Physics - Phenomenology · Physics 2016-08-24 William H. Kinney

In this paper, we study a constant-roll inflationary model in the presence of a noncommutative parameter with a homogeneous scalar field minimally coupled to gravity. The specific noncommutative inflation conditions proposed new…

High Energy Physics - Theory · Physics 2023-02-14 J. Sadeghi , S. Noori Gashti

In this paper we consider the $\alpha-$attractor model and study inflation under a non-slow-roll dynamics. More precisely, we follow the approach recently proposed by Gong and Sasaki \cite{Gong:2015ypa} by means of assuming…

General Relativity and Quantum Cosmology · Physics 2016-04-05 K. Sravan Kumar , João Marto , Paulo Vargas Moniz , Suratna Das

The linear and quadratic perturbations for a scalar-tensor model with non-minimal coupling to curvature, coupling to the Gauss-Bonnet invariant and non-minimal kinetic coupling to the Einstein tensor are developed. The quadratic action for…

General Relativity and Quantum Cosmology · Physics 2019-09-24 L. N. Granda , D. F. Jimenez

We study the possibility that inflation is driven by a scalar field together with a vector field minimally coupled to gravity. By assuming an effective potential that incorporates both fields into the action, we explore two distinct…

General Relativity and Quantum Cosmology · Physics 2024-12-09 Manuel Gonzalez-Espinoza , Ramon Herrera

We consider the constant-roll condition in the model of the inflaton nonminimal coupling to the Gauss-Bonnet term. By assuming the first Gauss-Bonnet flow parameter $\delta_1$ is a constant, we discuss the constant-roll inflation with…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Tie-Jun Gao

We have explicitly demonstrated that scalar coupled Gauss-Bonnet gravity in four dimension can have non-trivial effects on the early inflationary stage of our universe. In particular, we have shown that the scalar coupled Gauss-Bonnet term…

General Relativity and Quantum Cosmology · Physics 2018-11-13 Sumanta Chakraborty , Tanmoy Paul , Soumitra SenGupta

We study a single field inflationary model modified by a non-minimal coupling term between the Ricci scalar $R$ and the scalar field $\varphi$ in the context of constant-roll inflation. The first-order formalism is used to analyse the…

General Relativity and Quantum Cosmology · Physics 2021-08-11 Mehdi Shokri , Jafar Sadeghi , Mohammad Reza Setare , Salvatore Capozziello

In the light of the new observational results we discuss the status of the exponential potentials driving inflation. We depart form the minimal scenario and study an inflaton kinetically coupled to the Einstein tensor. We find that in this…

High Energy Physics - Theory · Physics 2014-11-05 Iannis Dalianis , Fotis Farakos

The inflation model with non-minimal coupling scalar field in the context of the hybrid metric Palatini is studied in this paper. We derive the Einstein's field equations, the equations of motion of the scalar field. Furthermore,the…

General Relativity and Quantum Cosmology · Physics 2024-02-29 Brahim Asfour , Aatifa Bargach , Ahmed Errahmani , Taoufik Ouali

We consider cosmological inflation generated by a scalar field slowly rolling off from a de Sitter maximum of its potential. The models belong to the class of hilltop models and represent the most general model of this kind in which the…

General Relativity and Quantum Cosmology · Physics 2016-09-05 Mariano Cadoni , Edgardo Franzin , Salvatore Mignemi

One common approach for cosmic inflation consists in couple Einstein's gravity with a scalar field, often referred to inflaton field. In order to derive analytic simple scenarios, we usually work in the {\it slow-roll} regime. In such an…

General Relativity and Quantum Cosmology · Physics 2021-01-01 J. R. L. Santos , P. H. R. S. Moraes

We derive the general formulae for the the scalar and tensor spectral tilts to the second order for the inflationary models with non-minimally derivative coupling without taking the high friction limit. The non-minimally kinetic coupling to…

General Relativity and Quantum Cosmology · Physics 2017-02-08 Nan Yang , Qin Fei , Qing Gao , Yungui Gong

We consider a Lorentz-violating theory of inflation consisting of Einstein-aether theory with a scalar inflaton coupled bilinearly to the expansion of the aether. We determine the conditions for linearized stability, positive energy, and…

General Relativity and Quantum Cosmology · Physics 2012-01-17 William Donnelly , Ted Jacobson

Slow-roll inflation is studied in theories where the inflaton field is conformally coupled to the Ricci scalar. In particular, the case of Higgs field inflation in the context of the noncommutative spectral action is analyzed. It is shown…

High Energy Physics - Theory · Physics 2010-08-31 Michel Buck , Malcolm Fairbairn , Mairi Sakellariadou

One of the fundamental objectives of contemporary cosmology is to understand the physics of the inflationary universe, owing to its observably verifiable predictions about the very early universe with an energy scale of $\sim 10^{16}$ GeV.…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-14 Aayush Randeep , Rajib Saha

We investigate the possibility of inflation with models of antisymmetric tensor field having minimal and nonminimal couplings to gravity. Although the minimal model does not support inflation, the nonminimal models, through the introduction…

General Relativity and Quantum Cosmology · Physics 2018-11-02 Sandeep Aashish , Abhilash Padhy , Sukanta Panda , Arun Rana

Transforming canonical scalars to the Einstein frame can give a multi-field generalization of pole inflation (namely, a scalar with a divergent kinetic term) at vanishing field-dependent Planck mass. However, to obtain an attractor, the…

High Energy Physics - Theory · Physics 2022-09-07 Sotirios Karamitsos , Alessandro Strumia