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The conventional background solution for the evolution of a single canonical inflaton field performs admirably in extreme scenarios such as the slow-roll phase (where the slow-roll parameter is much less than one) and the deep reheating era…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-26 Manjeet Kaur , Debottam Nandi , Sharath Raghavan B

The reconstruction of an inflationary universe considering the parametrization of the scalar spectral index as a function of the number of $e-$folds in the framework of a modified Friedmann equation is analyzed. In this context, we examine…

General Relativity and Quantum Cosmology · Physics 2024-09-12 Ramon Herrera , Carlos Rios

We consider the scale-invariant inflationary model studied in [1]. The Lagrangian includes all the scale-invariant operators that can be built with combinations of $R$, $R^2$ and one scalar field. The equations of motion show that the…

General Relativity and Quantum Cosmology · Physics 2017-03-14 Giovanni Tambalo , Massimiliano Rinaldi

We analyze the consequences of different evolutions of the Hubble parameter on the spectrum of scalar inflationary perturbations. The analysis is restricted to inflationary phases described by a transient evolution, when uncommon features…

General Relativity and Quantum Cosmology · Physics 2023-04-12 Leonardo Chataignier , Alexander Yu. Kamenshchik , Alessandro Tronconi , Giovanni Venturi

We suggest a new method to reconstruct, within canonical single-field inflation, the inflaton potential directly from the primordial power spectrum which may deviate significantly from near scale-invariance. Our approach relies on a more…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-12 Ki-Young Choi , Jinn-Ouk Gong , Su-beom Kang , Rathul Nath Raveendran

The reconstruction of an inflationary universe in the context of one $f(\phi)T$ gravity, in which $T$ corresponds to the trace of energy momentum tensor is studied. To realize this reconstruction during the inflationary epoch, we consider…

General Relativity and Quantum Cosmology · Physics 2023-10-12 Ramon Herrera , Carlos Rios

We analyse the dynamics of spinodal decomposition in inflationary cosmology using the closed time path formalism of out of equilibrium quantum field theory combined with the non-perturbative Hartree approximation. In addition to a general…

High Energy Physics - Phenomenology · Physics 2009-10-31 D. Cormier , R. Holman

We present new single field inflationary scenarios that produce the critical abundance of primordial black holes as dark matter reconstructing the inflaton potential from an input power spectrum. The method is exact in the slow roll…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-11 Gabriele Autieri , Michele Redi

Various scenarios of the initial inflation of the universe are distinguished by the choice of a scalar field {\em potential} $U(\phi)$ which simulates a {\it temporarily} non--vanishing {\em cosmological term}. Our new method, which…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Fjodor V. ~Kusmartsev , Eckehard W. ~Mielke , Yuri N. ~Obukhov , Franz E. ~Schunck

We describe a simple way of incorporating fluctuations of the Hubble scale during the horizon exit of scalar perturbations into the delta N formalism. The dominant effect comes from the dependence of the Hubble scale on low-frequency modes…

High Energy Physics - Theory · Physics 2010-08-12 Christian T. Byrnes , Mischa Gerstenlauer , Arthur Hebecker , Sami Nurmi , Gianmassimo Tasinato

The background evolution in two-field inflation can feature two distinct stages, corresponding to the evolution along two successive field directions. When the second stage occurs at a significantly lower energy scale, the inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-23 I. Dalianis , A. Katsis , N. Tetradis

Curvature perturbations with short wavelengths exit the Hubble horizon when the universe may contain a thermal plasma in addition to an inflaton field that drives its expansion. We solve the corresponding fluctuation-dissipation dynamics at…

High Energy Physics - Phenomenology · Physics 2026-01-05 M. Laine , S. Procacci , A. Rogelj

We apply the holographic principle at the early universe, obtaining an inflation realization of holographic origin. Such a consideration has equal footing with its well-studied late-time application, and moreover the decrease of the…

General Relativity and Quantum Cosmology · Physics 2019-08-14 Shin'ichi Nojiri , Sergei D. Odintsov , Emmanuel N. Saridakis

In this paper, we reconstruct viable inflationary models by starting from spectral index and tensor-to-scalar ratio from Planck observations. We analyze three different kinds of models: scalar field theories, fluid cosmology and…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Ratbay Myrzakulov , Lorenzo Sebastiani , Sergio Zerbini

One method to reconstruct the scalar field potential of inflation is a perturbative approach, where the values of the potential and its derivatives are calculated as an expansion in departures from the slow-roll approximation. They can then…

Astrophysics · Physics 2013-11-13 Edmund Copeland , Edward W. Kolb , Andrew R. Liddle , James E. Lidsey

In this paper the focus is on inflationary dynamics in the context of Einstein Gauss-Bonnet gravitational theories. We investigate the implications of the slow-roll condition on the slow-roll indices and we investigate how the inflationary…

General Relativity and Quantum Cosmology · Physics 2018-09-26 S. D. Odintsov , V. K. Oikonomou

Inflationary cosmology provides a successful paradigm for solving several problems, notably the generation of density perturbations which seed the formation of observed cosmic structure. We show how to use inverse scattering theory as the…

Astrophysics · Physics 2009-11-10 Salman Habib , Katrin Heitmann , Gerard Jungman

The reheating phase after inflation is one of the least observationally constrained epochs in the evolution of the Universe. The forthcoming gravitational wave observatories will enable us to constrain at least some of the non-standard…

High Energy Physics - Phenomenology · Physics 2024-06-24 Jose A. R. Cembranos , Mindaugas Karčiauskas

We present an explicit cosmological model where inflation and dark energy both could arise from the dynamics of the same scalar field. We present our discussion in the framework where the inflaton field $\phi$ attains a nearly constant…

High Energy Physics - Theory · Physics 2008-11-26 Ishwaree P. Neupane

We study inflationary dynamics using a recently introduced classical-quantum correspondence for investigating the backreaction of a quantum mechanical degree of freedom to a classical background. Using specifically a coupled…

General Relativity and Quantum Cosmology · Physics 2021-11-15 Reginald Christian Bernardo
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