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Related papers: Cosmological Singularities in Conformal Weyl Gravi…

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We present a comprehensive study of cosmological singularities within the framework of Covariant Extrinsic Gravity (CEG), addressing both the initial Big Bang singularity and potential finite-time future singularities. Through detailed…

General Relativity and Quantum Cosmology · Physics 2025-04-08 R. Jalalzadeh , S. Jalalzadeh , Y. Heydarzade

One resolution of the ancient cosmic singularity, i.e., the Big Bang Singularity (BBS), is to assume an inflationary stage preceded by a long enough static state in which the universe and its physical properties would oscillate around…

General Relativity and Quantum Cosmology · Physics 2025-05-01 Hamid Shabani , Avik De , Tee-How Loo

In this paper, in an FLRW background and a perfect fluid equation of state, we explore the possibility of the realization of an emergent scenario in a 4D regularized extension of Einstein-Gauss-Bonnet gravity, with the field equations…

General Relativity and Quantum Cosmology · Physics 2024-06-12 Mrinnoy M. Gohain , Kalyan Bhuyan

We explore the possibility of emergent cosmology using the effective potential formalism. We discover new models of emergent cosmology which satisfy the constraints posed by the cosmic microwave background (CMB). We demonstrate that, within…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Satadru Bag , Varun Sahni , Yuri Shtanov , Sanil Unnikrishnan

We present exact analytical solutions to the Conformal Weyl Gravity cosmological equations that are valid for both the matter and radiation dominated eras. The Primordial Nucleosynthesis process is also exhaustively studied. The main…

Astrophysics · Physics 2009-10-22 D. Elizondo , G. Yepes

We summarise the new conformal framework of an Anisotropic Future Endless Universe and an Anisotropic Future Singularity. Both new definitions are motivated by, but not restricted to quiescent cosmology and the Weyl curvature hypothesis,…

General Relativity and Quantum Cosmology · Physics 2010-01-25 Philipp A Hoehn , Susan M Scott

We show that a class of finite quantum non-local gravitational theories is conformally invariant at classical as well as at quantum level. This is actually a range of conformal anomaly-free theories in the spontaneously broken phase of the…

High Energy Physics - Theory · Physics 2018-09-03 Leonardo Modesto , Leslaw Rachwal

We explicitly prove that a class of finite quantum gravitational theories (in odd as well as in even dimension) is actually a range of anomaly-free conformally invariant theories in the spontaneously broken phase of the conformal Weyl…

High Energy Physics - Theory · Physics 2016-05-16 Leonardo Modesto , Leslaw Rachwal

The Einstein static (ES) universe has played a major role in various emergent scenarios recently proposed in order to cure the problem of initial singularity of the standard model of cosmology. In the herein model, we study the existence…

General Relativity and Quantum Cosmology · Physics 2017-01-23 Hamid Shabani , Amir Hadi Ziaie

We hereby address the cosmological singularity problem in a general gravitational theory invariant under Weyl conformal transformations. In particular, we focus on the Bianchi IX spacetime and we show that both the initial (big bang) and…

General Relativity and Quantum Cosmology · Physics 2026-01-21 Jiale Gu , Leonardo Modesto , Cosimo Bambi

Quiescent cosmology and the Weyl curvature hypothesis possess a mathematical framework, namely the definition of an Isotropic Singularity, but only for the initial state of the universe. A complementary framework is necessary to also encode…

General Relativity and Quantum Cosmology · Physics 2016-09-08 Philipp A Hoehn , Susan M Scott

The scenario of an emergent universe provides a promising resolution to the big bang singularity in universes with positive or negative spatial curvature. It however remains unclear whether the scenario can be successfully implemented in a…

General Relativity and Quantum Cosmology · Physics 2015-06-17 Kaituo Zhang , Puxun Wu , Hongwei Yu

Closed, singularity-free, inflationary cosmological models have recently been studied in the context of general relativity. Despite their appeal, these so called emergent models suffer from a number of limitations. These include the fact…

Astrophysics · Physics 2009-11-10 David J. Mulryne , Reza Tavakol , James E. Lidsey , George F. R. Ellis

We investigate a class of horizonless solutions in Einstein-Weyl gravity, corresponding to the so-called attractive naked singularities of the (-2,2) type. In contrast to General Relativity, where naked singularities are generically…

General Relativity and Quantum Cosmology · Physics 2025-11-14 Alfio M. Bonanno , Samuele Silveravalle , Andrea Spina

We discuss the cosmological evolution of the Weyl conformal geometry and its associated Weyl quadratic gravity. The Einstein gravity (with a positive cosmological constant) is recovered in the spontaneously broken phase of Weyl gravity;…

General Relativity and Quantum Cosmology · Physics 2022-06-24 D. M. Ghilencea , T. Harko

A possibility of journeys through antigravity has recently been proposed, with the suggestion that Weyl-invariant extension of scalars coupled to Einstein gravity allows for an unambiguous classical evolution through cosmological…

High Energy Physics - Theory · Physics 2015-06-17 John Joseph M. Carrasco , Wissam Chemissany , Renata Kallosh

We study the emergent scenario, which is proposed to avoid the big bang singularity, in the Einstein-Cartan (EC) theory with a positive cosmological constant and a perfect fluid by analyzing the existence and stability of the Einstein…

General Relativity and Quantum Cosmology · Physics 2015-10-19 Qihong Huang , Puxun Wu , Hongwei Yu

We investigate the cosmological evolution for the physical parameters in Weyl integrable gravity in a Friedmann--Lema\^{\i}tre--Robertson--Walker universe with zero spatially curvature. For the matter component, we assume that it is an…

General Relativity and Quantum Cosmology · Physics 2021-12-02 Andronikos Paliathanasis

We investigate the Einstein static universe (ESU) and the emergent universe scenario in the framework of Ho\v{r}ava-Lifshitz-like $F(R)$ gravity. We first perform a dynamical analysis in the phase space, and amongst others we show that a…

General Relativity and Quantum Cosmology · Physics 2016-06-10 M. Khodadi , Y. Heydarzade , F. Darabi , E. N. Saridakis

In this paper we explore the physical consequences of assuming Weyl invariance of the laws of gravity from the classical standpoint exclusively. Actual Weyl invariance requires to replace the underlying Riemannian geometrical structure of…

General Relativity and Quantum Cosmology · Physics 2020-04-20 Israel Quiros
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