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We study inflation within the framework of non-canonical scalar field. In this scenario, we obtain the inflationary observables such as the scalar spectral index, the tensor-to-scalar ratio, the running of the scalar spectral index as well…

General Relativity and Quantum Cosmology · Physics 2017-05-31 Zeinab Teimoori , Kayoomars Karami

An approach to construct cosmological inflation models on the basis of a certain dependence of the scalar field evolution on the e-folds number is considered. The reconstruction of the model background parameters according to the kind of…

General Relativity and Quantum Cosmology · Physics 2025-12-23 Igor V. Fomin , Vladimir L. Glushkov , Evgenii S. Dentsel , Gevorg D. Manucharyan , Vyacheslav A. Sizov

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

I study a thermodynamical approach to scalar metric perturbations during the inflationary stage. In the power-law expanding universe here studied, I find a negative heat capacity as a manifestation of superexponential growing for the number…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Mauricio Bellini

This study explores the interaction between non-extensive entropic FLRW cosmology and the power-law inflationary model, with a focus on the overlap between the scalar spectral index `$n_s$' and the tensor-to-scalar ratio `$r$'. Based on a…

General Relativity and Quantum Cosmology · Physics 2024-09-26 A. Khodam-Mohammadi

Power-Law inflation with scale factor $a \propto t^m$ is investigated in the context of warm inflation. The treatment is performed in the weak and strong dissipation limits. In addition, we discuss the three common cases for the thermal…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-12 M. Alhallak , N. Chamoun , M. S. Eldaher

The inflationary and pre-inflationary evolution of scalar modes of cosmological perturbations in a closed universe is analyzed for a loop quantum cosmology model with an inflationary regime consistent with the constraints on inflation…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

We identify a new inflationary regime for which more than 60 e-folds are generated classically during the waterfall phase occuring after the usual hybrid inflation. By performing a bayesian Monte-Carlo-Markov-Chain analysis, this scenario…

General Relativity and Quantum Cosmology · Physics 2011-03-22 Sebastien Clesse

We present some features of early universe cosmology in terms of Hankel functions index ($\nu$). Actually, the recent data from observational cosmology indicate that our universe was nearly de Sitter space-time in the early times which…

High Energy Physics - Theory · Physics 2018-04-06 E. Yusofi , M. Mohsenzadeh

The trans-Planckian censorship conjecture (TCC) puts an upper bound on the life-time of de Sitter spacetimes. It has immediate consequences for inflationary cosmology. In the standard paradigm, the universe has experienced a single stage of…

High Energy Physics - Theory · Physics 2020-03-18 Mahdi Torabian

The effect of the initial conditions in inflation on scalar and tensor perturbations is investigated. Formulae for the power spectra of gravitational waves and curvature perturbations for any initial conditions in inflation are derived, and…

High Energy Physics - Theory · Physics 2007-05-23 Shiro Hirai

We consider a novel model of cosmic inflation. In our model one does not need any specific matter field to drive inflation, but inflation stems from the microscopic, Planck scale structure of spacetime, thus being of quantum gravitational…

General Relativity and Quantum Cosmology · Physics 2014-08-28 Jarmo Mäkelä

The BB-mode angular correlation power spectrum of CMB is obtained by considering the primordial gravitational waves in the squeezed vacuum state for various inflationary models and results are compared with the joint analysis of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 N. Malsawmtluangi , P. K. Suresh

The single scalar field inflationary models that lead to scalar and tensor perturbation spectra with amplitudes varying in direct proportion to one another are reconstructed by solving the Stewart-Lyth inverse problem to next-to-leading…

Astrophysics · Physics 2009-11-07 C. A. Terrero-Escalante , James E. Lidsey , Alberto A. Garcia

$k$-inflation represents the most general single-field inflation, in which the perturbations usually obey an equation of motion with a time-dependent sound speed. In this paper, we study the observational predictions of the $k$-inflation by…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-19 Tao Zhu , Anzhong Wang , Gerald Cleaver , Klaus Kirsten , Qin Sheng

In a previous paper we proposed a new approach to the beginning of inflation -- a lingering universe. The universe begins in a lingering state with a nearly vanishing Hubble parameter. This calls into question the absolute age of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-09 Brandon Melcher , Arnab Pradhan , Scott Watson

The inflationary mechanism of mode amplification predicts that the state of each mode with a given wave vector is correlated to that of its partner mode with the opposite vector. This implies nonlocal correlations which leave their imprint…

General Relativity and Quantum Cosmology · Physics 2009-11-10 David Campo , Renaud Parentani

A scale-invariant universe can have a period of accelerated expansion at early times: inflation. We use a frame-invariant approach to calculate inflationary observables in a scale invariant theory of gravity involving two scalar fields -…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-26 Pedro G. Ferreira , Christopher T. Hill , Johannes Noller , Graham G. Ross

It is well understood that spatial non-commutativity, if indeed realized in nature, is a phenomenon whose effects are not just felt at energy scales comparable to the non-commutativity scale. Loop effects can transmit signatures of any…

High Energy Physics - Theory · Physics 2009-11-05 Gonzalo A. Palma , Subodh P. Patil

We study power law inflation in the context of non-minimally coupled to the scalar curvature. We analyze the inflationary solutions under an exact analysis and also in the slow roll approximation. In both solutions, we consider the recent…

General Relativity and Quantum Cosmology · Physics 2015-08-06 Sergio del Campo , Carlos Gonzalez , Ramon Herrera