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Related papers: Topological Early Universe Cosmology

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We investigate cosmological models in a recently proposed geometrical theory of gravity, in which the scalar field appears as part of the space-time geometry. We extend the previous theory to include a scalar potential in the action. We…

General Relativity and Quantum Cosmology · Physics 2016-09-14 M. L. Pucheu , F. A. P. Alves-Junior , A. B. Barreto , C. Romero

Giving up Einstein's assumption, implicit in his 1916 field equations, that inertial mass, even in its appearance as energy, is equivalent to active gravitational mass and therefore is a source of gravity allows revising the field equations…

General Relativity and Quantum Cosmology · Physics 2016-03-18 Homer G. Ellis

A perfect fluid, spatially flat cosmology in a $f(T)$ model, derived from a recently proposed general Born-Infeld type theory of gravity is studied. Four dimensional cosmological solutions are obtained assuming the equation of state…

General Relativity and Quantum Cosmology · Physics 2014-12-04 Soumya Jana

This article examines how the physical presence of field energy and particulate matter can be interpreted in terms of the topological properties of space-time. The theory is developed in terms of vector and matrix equations of exterior…

General Relativity and Quantum Cosmology · Physics 2007-12-10 R. M. Kiehn

The approximate homogeneity of spatial sections of the Universe is well supported observationally, but the inhomogeneity of the spatial sections is even better supported. Here, we consider the implications of inhomogeneity in dust models…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-20 Boudewijn F. Roukema , Vincent Blanloeil , Jan J. Ostrowski

Seiberg-Witten theory leads to a delicate interplay between Riemannian geometry and smooth topology in dimension four. In particular, the scalar curvature of any metric must satisfy certain non-trivial estimates if the manifold in question…

Differential Geometry · Mathematics 2016-09-07 Claude LeBrun

We consider a non singular origin for the Universe starting from an Einstein static Universe, the so called "emergent universe" scenario, in the framework of a theory which uses two volume elements $\sqrt{-{g}}d^{4}x$ and $\Phi d^{4}x$,…

General Relativity and Quantum Cosmology · Physics 2015-05-27 E. I. Guendelman

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

An alternative formulation of the no-boundary initial state of the universe in the Euclidean quantum theory of gravity is proposed. Unlike the no-boundary Hartle-Hawking wave function, in which time appears together with macroscopic…

General Relativity and Quantum Cosmology · Physics 2023-10-24 Natalia Gorobey , Alexander Lukyanenko , A. V. Goltsev

Based on an earlier introduced new class of generalized gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold, we…

High Energy Physics - Theory · Physics 2016-11-29 Eduardo Guendelman , Ramon Herrera , Pedro Labrana , Emil Nissimov , Svetlana Pacheva

It is known that if gauge conditions have Gribov zero modes, then topological symmetry is broken. In this paper we apply it to topological gravity in dimension $n \geq 3$. Our choice of the gauge condition for conformal invariance is…

High Energy Physics - Theory · Physics 2015-06-26 Akifumi Sako

In this work, we study the issue of the past and future cosmological singularities in the context of the fourth-order conformal Weyl gravity. In particular, we investigate the emergent universe scenario proposed by Ellis {\it et al}, and…

General Relativity and Quantum Cosmology · Physics 2020-06-02 Yaghoub Heydarzade

In the late 1990s, observations of type Ia supernovae led to the astounding discovery that the universe is expanding at an accelerating rate. The explanation of this anomalous acceleration has been one of the great problems in physics since…

General Physics · Physics 2015-11-09 Wun-Yi Shu

Topological defects are common in many everyday systems. In general, they appear if a symmetry is broken at a rapid phase transition. In this article, I explain why it is believed that they should have also been formed in the early universe…

Astrophysics · Physics 2007-05-23 A. Rajantie

A free scalar field minimally coupled to gravity model is quantized and the Wheeler-DeWitt equation in minisuperspace is solved analytically, exhibiting positive and negative frequency modes. The analysis is performed for positive, negative…

General Relativity and Quantum Cosmology · Physics 2009-10-31 R. Colistete , J. C. Fabris , N. Pinto-Neto

We develop a comprehensive cosmological framework based on the principle that our universe originated as a three-dimensional spatial configuration governed purely by energy functionals, with time emerging dynamically through quantum loop…

General Physics · Physics 2026-01-13 Farrukh A. Chishtie

We consider the no-boundary proposal for homogeneous isotropic closed universes with a cosmological constant and a scalar field with a quadratic potential. In the semi-classical limit, it predicts classical behavior at late times if the…

High Energy Physics - Theory · Physics 2008-11-26 James B. Hartle , S. W. Hawking , Thomas Hertog

The global topology of the Universe could, in principle, affect quantum systems through boundary condition constraints. We investigate this connection by analyzing how compact, flat, cosmologically inspired topologies, specifically the…

Quantum Physics · Physics 2025-05-14 Evangelos Achilleas Paraskevas , Leandros Perivolaropoulos

Friedmann-Lemaitre equations with contributions coming from matter, curvature, cosmological constant, and radiation, when written in terms of conformal time u rather than in terms of cosmic time t, can be solved explicitly in terms of…

General Relativity and Quantum Cosmology · Physics 2018-09-12 Robert Coquereaux

We propose that the Universe was created from "Nothing" with a relatively small particles number and it very quick relaxed to quasiequilibrium state at the Planck parameters. The classic cosmological solution for this Universe, with the…

Astrophysics · Physics 2009-10-28 V. Burdyuzha , Yu. Ponomarev , O. Lalaculich , G. Vereshkov
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