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This paper investigates a scale-invariant inflationary model characterized by a scalar field non-minimally coupled to gravity and a curvature term quadratic in the Ricci scalar. The model's dynamic is analyzed using a full numerical…

High Energy Physics - Theory · Physics 2024-10-10 Mariaveronica De Angelis , Chiara Cecchini , Massimiliano Rinaldi

We study the intermediate inflation in a non-canonical scalar field framework with a power-like Lagrangian. We show that in contrast with the standard canonical intermediate inflation, our non-canonical model is compatible with the…

General Relativity and Quantum Cosmology · Physics 2015-09-24 K. Rezazadeh , K. Karami , P. Karimi

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

We derive general analytic formulae for the power spectrum and spectral index of the curvature perturbation produced during inflation driven by a multi-component inflaton field, up to the second order in the slow-roll approximation. We do…

Astrophysics · Physics 2009-10-28 Takahiro T. Nakamura , Ewan D. Stewart

We study cosmological perturbations in generalized Einstein scenarios and show the equivalence of inflationary observables both in the Jordan frame and the Einstein frame. In particular the consistency relation relating the tensor-to-scalar…

Astrophysics · Physics 2010-11-23 Shinji Tsujikawa , Burin Gumjudpai

We examine inflationary universe models driven by scalar fields with logarithmic potentials of the form $V(\phi) = V_0 \phi^p(\ln \phi)^q$. Combining the slow-roll approximation with asymptotic techniques, we identify regions of the…

Astrophysics · Physics 2009-10-28 John D. Barrow , Paul Parsons

We embed general $f(R)$ inflationary models in minimal supergravity plus matter, a single chiral superfield $\Phi$, with or without another superfield $S$, via a Jordan frame Einstein+scalar description. In particular, inflationary models…

High Energy Physics - Theory · Physics 2016-02-17 Horatiu Nastase

A stiff matter-dominated universe modeled by a free massless scalar field minimally coupled to gravity in a Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) geometry is quantized. Generalized complex-width gaussian superpositions of the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Felipe T. Falciano , Nelson Pinto-Neto , E. Sergio Santini

We propose a model for cosmic inflation which is based on an effective description of strongly interacting, nonsupersymmetric matter within the framework of dynamical Abelian projection and centerization. The underlying gauge symmetry is…

High Energy Physics - Phenomenology · Physics 2009-11-07 Ralf Hofmann , Mathias Th. Keil

We study cosmological perturbations generated from quantum fluctuations in multi-field inflationary scenarios in generalized Einstein theories, taking both adiabatic and isocurvature modes into account. In the slow-roll approximation,…

Astrophysics · Physics 2009-11-07 Alexei A. Starobinsky , Shinji Tsujikawa , Jun'ichi Yokoyama

Recent cosmic microwave background observations favor low energy scale inflationary models in a closed universe. However, onset of inflation in such models for a closed universe is known to be severely problematic. In particular, such a…

General Relativity and Quantum Cosmology · Physics 2021-03-03 Lucia Gordon , Bao-Fei Li , Parampreet Singh

We discuss the cosmological inflation in the context of $f(Q)$ non-metric gravity, where $Q$ is the non-metric scalar. After introducing conformal transformations for $f(Q)$ gravity, we first focus on the potential-slow-roll inflation by…

General Relativity and Quantum Cosmology · Physics 2022-09-23 Salvatore Capozziello , Mehdi Shokri

We show how we can implement chaotic inflation in the context of supergravity by conveniently selecting the functional form of a strong enough non-minimal coupling between the inflaton and the Ricci scalar curvature. The procedure can be…

High Energy Physics - Phenomenology · Physics 2014-12-12 C. Pallis

We study early universe with a particular form of F(T) Telleparallel gravity theory, in which inflation is driven by a scalar field. To ensure slow rollover, two different potentials are chosen in a manner, such that they remain almost flat…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-20 Manas Chakrabortty , Nayem Sk , Susmita Sanyal , Abhik Kumar Sanyal

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 investigate intermediate inflation in the framework of a Galileon scalar field. To this aim, we first obtain the inflationary observables, including the scalar spectral index, the tensor-to-scalar ratio, the running of the scalar…

General Relativity and Quantum Cosmology · Physics 2018-09-03 Zeinab Teimoori , Kayoomars Karami

We study cosmological inflation on a warped DGP braneworld where inflaton field is non-minimally coupled to induced gravity on the brane. We present a detailed calculation of the perturbations and inflation parameters both in Jordan and…

General Relativity and Quantum Cosmology · Physics 2015-06-05 Kourosh Nozari , Narges Rashidi

We study inflation in the framework of $f(T)$-gravity in the presence of a canonical scalar field. After reviewing the basic equations governing the background cosmology in $f(T)$-gravity, we turn to study the cosmological perturbations and…

General Relativity and Quantum Cosmology · Physics 2016-02-02 K. Rezazadeh , A. Abdolmaleki , K. Karami

We propose a model for cosmic inflation which is based on an effective description of strongly interacting, nonsupersymmetric matter within the framework of dynamical abelian projection and centerization. The underlying gauge symmetry is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ralf Hofmann , Mathias Th. Keil

Inflationary cosmology proposes that the early Universe undergoes accelerated expansion, driven, in simple scenarios, by a single scalar field, or inflaton. The form of the inflaton potential determines the initial spectra of density…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 Richard Easther , Benedict Bahr-Kalus , David Parkinson
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