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Related papers: Early Universe Cosmology in Internal Relativity

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Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion…

High Energy Physics - Phenomenology · Physics 2014-11-17 Scott Dodelson

Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may…

We study the effects of various phenomena which may have happened in the early universe on the spectrum of inflationary gravitational waves. The phenomena include phase transitions, entropy productions from non-relativistic matter, the…

High Energy Physics - Phenomenology · Physics 2015-06-16 Ryusuke Jinno , Takeo Moroi , Kazunori Nakayama

In this letter, we propose a model of inflationary cosmology with a bounce preceded and study its primordial curvature perturbations. Our model gives rise to a primordial power spectrum with a feature of oscillation on large scales compared…

Astrophysics · Physics 2009-02-02 Yi-Fu Cai , Tao-tao Qiu , Jun-Qing Xia , Xinmin Zhang

We study the origin of the universe (or pre-inflation) by suggesting that the primordial space-time in the universe suffered a global topological phase transition, from a 4D Euclidean manifold to an asymptotic 4D hyperbolic one. We…

General Relativity and Quantum Cosmology · Physics 2017-07-21 Mauricio Bellini

Warm inflation is an interesting possibility of describing the early universe, whose basic feature is the absence, at least in principle, of a preheating or reheating phase. Here we analyze the dynamics of warm inflation generalizing the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 H. P. De Oliveira , S. E. Jorás

We present a new version of holographic cosmology, which is compatible with present observations. A primordial $p=\rho$ phase of the universe is followed by a brief matter dominated era and a brief period of inflation, whose termination…

High Energy Physics - Theory · Physics 2014-11-18 T. Banks , W. Fischler

Loop quantum cosmology provides an efficient framework to study the evolution of the Universe beyond the classical Big Bang paradigm. Because of holonomy corrections, the singularity is replaced by a "bounce". The dynamics of the background…

General Relativity and Quantum Cosmology · Physics 2015-03-13 Jakub Mielczarek , Thomas Cailleteau , Julien Grain , Aurelien Barrau

We provide a realisation of a singularity-free inflationary universe in the form of a simple cosmological model dominated at early times by a single minimally coupled scalar field with a physically based potential. The universe starts…

General Relativity and Quantum Cosmology · Physics 2008-11-26 George F. R. Ellis , Jeff Murugan , Christos G. Tsagas

We discuss metric perturbations produced during a period of inflation in the early universe where two scalar fields evolve. The final scalar perturbation spectrum can be calculated in terms of the perturbed expansion along neighbouring…

Astrophysics · Physics 2007-05-23 David Wands , Juan Garcia-Bellido

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

The post-inflationary epochs are critical for comprehending the early evolution of our Universe. This article delves into the cosmological signatures that shed light on these early epochs, particularly focusing on the generation of various…

General Relativity and Quantum Cosmology · Physics 2024-12-24 K. El Bourakadi , Z. Sakhi , M. Bennai

A new idea of deriving a cosmological term from an underlying theory has been proposed in order to explain the expansion history of the universe. We obtain the scale factor with this derived cosmological term and demonstrate that it…

General Relativity and Quantum Cosmology · Physics 2008-10-15 Supratik Pal

Flat space cosmology spacetimes are exact time-dependent solutions of 3-dimensional gravity theories, such as Einstein gravity or topologically massive gravity. We exhibit a novel kind of phase transition between these cosmological…

High Energy Physics - Theory · Physics 2013-11-13 Arjun Bagchi , Stephane Detournay , Daniel Grumiller , Joan Simon

A new class of gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold are studied in some detail. These models involve…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Eduardo Guendelman , Ramón Herrera , Pedro Labraña , Emil Nissimov , Svetlana Pacheva

In most current models of inflation based on a weakly self-coupled scalar matter field minimally coupled to gravity, the period of inflation lasts so long that, at the beginning of the inflationary period, the physical wavelengths of…

High Energy Physics - Theory · Physics 2008-11-26 Jerome Martin , Robert H. Brandenberger

A brief review of the modern state of quantum cosmology is presented as a theory of quantum initial conditions for inflationary scenario. The no-boundary and tunneling states of the Universe are discussed as a possible source of probability…

General Relativity and Quantum Cosmology · Physics 2017-08-23 A. O. Barvinsky

Recently, it has been showed that a slow expansion, which is asymptotically a static state in infinite past and may be described as an evolution with \epsilon \ll -1, of early universe may lead to the generation of primordial perturbation…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Yun-Song Piao

In order to draw out the essential behavior of the universe, investigations of early universe cosmology often reduce the complex system to a simple integrable system. Inflationary models are of this kind as they focus on simple scalar field…

Astrophysics · Physics 2009-10-28 Neil J. Cornish , Janna J. Levin

We wish to demonstrate how the presence of a dynamic cosmological parameter, plus a model of the universe as a quantum computer can be combined to give us a picture of early universe inflationary physics which is quite non linear, with a…

Mathematical Physics · Physics 2011-11-10 A. W. Beckwith