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The generic prediction for the perturbations generated during slow--roll, single--field inflation, as they appear in the cosmic microwave background (CMB), is a flat, close--to--Gaussian spectrum. We calculate the general solution for a…

Astrophysics · Physics 2007-05-23 S. Gupta

We study the statistics of scalar perturbations in models of inflation with small and rapid oscillations in the inflaton potential (resonant non-Gaussianity). We do so by deriving the wavefunction $\Psi[\zeta(\boldsymbol{x})]$…

High Energy Physics - Theory · Physics 2024-03-05 Paolo Creminelli , Sébastien Renaux-Petel , Giovanni Tambalo , Vicharit Yingcharoenrat

For variable gravity models the strength of gravity, as measured by Newton's ``constant'' or the Planck mass, depends on the value of a scalar field, the cosmon. We discuss two simple four-parameter models with a quadratic or constant…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-15 C. Wetterich

A viable model for inflation driven by a torsion function in a Friedmann background is presented. The scalar spectral index in the interval $0.92\lesssim n_{s}\lesssim 0.97$ is obtained in order to satisfy the initial conditions for…

General Relativity and Quantum Cosmology · Physics 2022-09-22 T. M. Guimarães , R. de C. Lima , S. H. Pereira

The previously proposed modification of the standard (flat) inflationary $\Lambda CDM$ model in which the inflaton field(s) and ``dark energy" are replaced by the vacum in expanding Friedmann-Lema\^itre-Robertson-Walker Universe is studied.…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Robert Alicki

During the inflationary epoch,geometry of the universe may be described by quasi-de Sitter space. On the other hand,maximally extended de Sitter metric in the comoving coordinates accords with a special FLRW model with positive spatial…

General Relativity and Quantum Cosmology · Physics 2016-01-20 A. A. Asgari , A. H. Abbassi

We study a scale-invariant model of quadratic gravity with a non-minimally coupled scalar field. We focus on cosmological solutions and find that scale invariance is spontaneously broken and a mass scale naturally emerges. Before the…

General Relativity and Quantum Cosmology · Physics 2016-07-13 Massimiliano Rinaldi , Luciano Vanzo

We present a unified framework that simultaneously addresses the dynamics of early-time cosmic inflation and late-time cosmic acceleration within the context of a single scalar field non-minimally coupled to gravity. By employing an…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Seong Chan Park

In this paper we consider a new approach to unify inflation and the late universe with dark energy and dark matter formulated in a model that includes a non-Riemannian metric independent measure and a scalar field with spontaneously broken…

General Relativity and Quantum Cosmology · Physics 2025-01-31 Eduardo Guendelman , Ramon Herrera

In this paper we investigate the asymptotic dynamics of inflationary cosmological models that are based in scalar-tensor theories of gravity. Our main aim is to explore the global structure of the phase space in the framework of…

General Relativity and Quantum Cosmology · Physics 2020-05-20 Israel Quiros , Tame Gonzalez , Roberto De Arcia , Ricardo García-Salcedo , Ulises Nucamendi , Joel F. Saavedra

There is strong evidence from cosmological data that the universe underwent an epoch of superluminal expansion called inflation. A satisfactory embedding of inflation in fundamental physics has been an outstanding problem at the interface…

High Energy Physics - Phenomenology · Physics 2008-12-26 Rouzbeh Allahverdi

A huge value of cosmological constant characteristic for the particle physics and the inflation of early Universe are inherently related to each other: one can construct a fine-tuned superpotential, which produces a flat potential of…

General Relativity and Quantum Cosmology · Physics 2015-06-03 V. V. Kiselev , S. A. Timofeev

We propose a model of inflation with a suitable potential for a single scalar field which falls in the wide class of hilltop inflation. We derive the analytical expressions for most of the physical quantities related to inflation and show…

High Energy Physics - Theory · Physics 2010-01-28 Barun Kumar Pal , Supratik Pal , B. Basu

In the primordial universe, fields with mass much larger than the mass-scale of the event-horizon (such as the Hubble parameter in inflation) exist ubiquitously, and can be excited from time to time and oscillate quickly around their…

High Energy Physics - Theory · Physics 2011-06-28 Xingang Chen

We briefly review the arising of an inflationary phase in the Universe evolution in order to discuss an inhomogeneous cosmological solution in presence of a real self interacting scalar field minimally coupled to gravity in the region of a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giovanni Imponente

In order to solve the fine-tuning problem of the cosmological constant, we propose a simple model with the vacuum energy non-minimally coupled to the inflaton field. In this model, the vacuum energy decays to the inflaton during…

General Relativity and Quantum Cosmology · Physics 2016-06-27 Chao-Qiang Geng , Chung-Chi Lee

In this review I consider several different issues related to inflation. I will begin with the wave function of the Universe. This issue is pretty old, but recently there were some new insights based on the theory of the self-reproducing…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Andrei Linde

This paper investigates Starobinsky's model of inflation driven by the trace anomaly of conformally coupled matter fields. This model does not suffer from the problem of contrived initial conditions that occurs in most models of inflation…

High Energy Physics - Theory · Physics 2009-10-31 S. W. Hawking , T. Hertog , H. S. Reall

The chaotic inflationary model of the early universe, proposed by Linde is explored in the brane world considering matter described by a minimally coupled self interacting scalar field. We obtain cosmological solutions which admit evolution…

High Energy Physics - Theory · Physics 2009-11-10 Bikash Chandra Paul

We study inflationary universe models that are characterized by a single scalar inflaton field. The study of these models are based on two dynamical equations; one corresponding to the Klein-Gordon equation for the inflaton field, and the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Sergio del Campo