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There is now overwhelming observational evidence that our Universe is accelerating in its expansion. I discuss how modified gravitational models can provide an explanation for this observed late-time cosmic acceleration. We consider…

Astrophysics · Physics 2008-11-26 Damien A. Easson

We investigate the inflationary expansion of the universe induced by higher curvature corrections in M-theory. The inflationary evolution of the geometry is discussed in ref.[1], thus we succeed to analyse metric perturbations around the…

High Energy Physics - Theory · Physics 2020-09-15 Kazuho Hiraga , Yoshifumi Hyakutake

For the Poincare gauge theory of gravity we consider the dynamical scalar torsion mode in a cosmological context. We explore in particular the possibility of using dynamical torsion to explain the current state of the accelerating Universe.…

Astrophysics · Physics 2008-11-26 Hwei-Jang Yo , James M. Nester

We review the current standard model for the evolution of the Universe from an early inflationary epoch to the complex hierarchy of structure seen today. We summarize and provide key references for the following topics: observations of the…

Astrophysics · Physics 2009-06-23 Bharat Ratra , Michael S. Vogeley

Inflation is a bold and expansive extension of the Standard Cosmology. It holds the promise to extend our understanding of the Universe to within 10^{-32}sec of the big bang and answer most of the pressing questions in cosmology. Its…

Astrophysics · Physics 2007-05-23 Michael S. Turner

After a brief summary of general relativity and cosmology, we present the basic concepts underlying inflation, the currently best motivated models for the early Universe. We describe the simplest inflation models, based on a single scalar…

General Relativity and Quantum Cosmology · Physics 2008-11-27 David Langlois

The incorporation of bulk viscosity process to General Relativity leads to the appearance of nonsingular backgrounds that, at early and late times, depict an accelerated universe. These backgrounds could be analytically calculated and…

General Relativity and Quantum Cosmology · Physics 2017-12-20 Jaume Haro , Supriya Pan

In this article, we consider a bouncing Universe, as described for example by Loop Quantum Cosmology. If the current acceleration is due to a true cosmological constant, this constant is naturally conserved through the bounce and the…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Aurelien Barrau , Linda Linsefors

Dynamics of the inflaton scalar field oscillating around a minimum of the singular potentials in the expanding Universe is investigated. Asymptotic formulas are obtained describing the cosmological expansion at the late times. The problem…

General Relativity and Quantum Cosmology · Physics 2017-03-22 Vladimir A. Koutvitsky , Eugene M. Maslov

In this work we propose a new general model of eternal cyclic Universe. We start from the assumption that quantum gravity corrections can be effectively accounted by the addition of higher order curvature terms in the Lagrangian density for…

General Relativity and Quantum Cosmology · Physics 2017-06-06 Petar Pavlovic , Marko Sossich

The effect of the global rotation of the universe on the formation of galaxies is investigated. It is found that the global rotation provides a natural origin for the rotation of galaxies, and the morphology of the objects formed from…

Astrophysics · Physics 2015-06-24 Li-Xin Li

An introductory account is given of the inflationary cosmology, which postulates a period of accelerated expansion during the Universe's earliest stages. The historical motivation is briefly outlined, and the modelling of the inflationary…

Astrophysics · Physics 2007-05-23 Andrew R Liddle

As a sequel to (Berman, 2008a), we show that the rotation of the Universe can be dealt by generalised Gaussian metrics, defined in this paper. Robertson-Walker's metric has been employed with proper-time, in its standard applications; the…

General Physics · Physics 2009-11-13 Marcelo Samuel Berman

The cosmological model best capable of fitting current observational data features two separate epochs during which the Universe is accelerating. During the earliest stages of the Universe, such acceleration is known as cosmological…

Astrophysics · Physics 2009-10-31 Andrew R Liddle

A gauge-invariant, linear cosmological perturbation theory of an almost homogeneous and isotropic universe with dynamically evolving Newton constant G and cosmological constant $\Lambda$ is presented. The equations governing the evolution…

General Relativity and Quantum Cosmology · Physics 2011-04-22 Adriano Contillo

By extending the potential, we propose a mechanism for the end of the constant-roll inflation and the subsequent reheating phase in the FLRW space-time. Based on astrophysical data, we estimate the Universe reheating temperature.

General Relativity and Quantum Cosmology · Physics 2020-01-22 H. Mohseni Sadjadi , V. Anari

Previously defined covariant and gauge-invariant perturbation variables, representing, e.g., the fractional spatial energy density gradient on hypersurfaces of constant expansion, are used to simplify the linear perturbation analysis of a…

Astrophysics · Physics 2009-10-30 Winfried Zimdahl

If the spatial curvature of the universe is positive, then the curvature term will always dominate at early enough times in a slow-rolling inflationary epoch. This enhances inflationary effects and hence puts limits on the possible number…

General Relativity and Quantum Cosmology · Physics 2015-06-25 G. F. R. Ellis , W. Stoeger , P. McEwan , P. Dunsby

In the frame of multifractal theory of time and space (in this model our universe is consisting of real time and space fields and is the multifractal universe) in the works [1]-[16] some problems were analyzed: how the fractional dimensions…

General Physics · Physics 2007-05-23 L. Ya. Kobelev

We analyze dynamics of the FRW models with global rotation in terms of dynamical system methods. We reduce dynamics of these models to the FRW models with some fictitious fluid which scales like radiation matter. This fluid mimics…

Astrophysics · Physics 2009-11-10 Wlodzimierz Godlowski , Marek Szydlowski