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Related papers: A modified Friedmann equation

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A simple and surprisingly realistic model of the origin of the universe can be developed using the Friedmann equation from general relativity, elementary quantum mechanics, and the experimental values of h, c, G and the proton mass. The…

General Relativity and Quantum Cosmology · Physics 2015-06-25 T. R. Mongan

We describe a model where breaking of W3 symmetry will lead to the emergence of time and subsequently of space. Surprisingly the simplest such models which lead to higher dimensional spacetimes are based on the four "magical" Jordan…

High Energy Physics - Theory · Physics 2017-05-03 J. Ambjorn , Y. Watabiki

An interesting idea is that the universe could be spontaneously created from nothing, but no rigorous proof has been given. In this paper, we present such a proof based on the analytic solutions of the Wheeler-DeWitt equation (WDWE).…

General Relativity and Quantum Cosmology · Physics 2014-04-07 Dongshan He , Dongfeng Gao , Qing-yu Cai

We show in the paper that Friedman universes can be created from empty, flat Minkowski spacetime by using suitable conformal rescaling of the spacetime metric.

General Relativity and Quantum Cosmology · Physics 2015-03-13 Janusz Garecki

We show how our Universe can emerge from a symmetry breaking of a multicomponent $W_3$ algebra, where the components in addition form a Jordan algebra. We discuss how symmetry breaking related to the Jordan algebras $H_3(C)$ and $H_3(O)$…

General Relativity and Quantum Cosmology · Physics 2026-01-16 Jan Ambjorn , Yoshiyuki Watabiki

In this work we demonstrate that wormholes can in principle be naturally created during the cosmological bounce without the need for the exotic matter or any kind of additional modifications of the gravitational sector, apart from the one…

General Relativity and Quantum Cosmology · Physics 2025-02-07 Petar Pavlović , Marko Sossich

Could one start from scratch, ignore relativity theory and quantum theory, create and expand our 3-D universe with no singularities, have the mathematical model predict correctly all of the cosmological parameters, provide the origins and…

Astrophysics · Physics 2007-05-23 Charles B. Leffert

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $\Lambda>0$ for a general linear equation of state…

General Relativity and Quantum Cosmology · Physics 2016-08-31 A. S. Silbergleit

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $\Lambda>0$ for a general linear equation of state…

Astrophysics · Physics 2009-11-07 A. S. Silbergleit

We develop a new approach to building cosmological models, in which small pieces of perturbed Minkowski space are joined together at reflection-symmetric boundaries in order to form a global, dynamical space-time. Each piece of this…

General Relativity and Quantum Cosmology · Physics 2016-04-12 Viraj A. A. Sanghai , Timothy Clifton

We point out that a simple late-time cosmological model where our Universe can absorb "baby universes" explains the exponential expansion of our universe without the need of a cosmological constant and leads to a z-dependence of the…

General Relativity and Quantum Cosmology · Physics 2026-05-15 Jan Ambjorn , Yoshiyuki Watabiki

The theoretical and observational consequences of thermodynamics of open systems, which allow particle creation are investigated in modified $f(R,T)$ ($R$ is the Ricci scalar and $T$ is the trace of energy-momentum tensor) theory of gravity…

General Relativity and Quantum Cosmology · Physics 2014-08-26 C. P. Singh , Vijay Singh

We address the question of universes inside a $\Lambda$ black hole which is described by a spherically symmetric globally regular solution to the Einstein equations with a variable cosmological term $\Lambda_{\mu\nu}$, asymptotically…

General Relativity and Quantum Cosmology · Physics 2009-11-07 I. G. Dymnikova , A. Dobosz , M. L. Fil'chenkov , A. Gromov

We discuss the essential features of baby-universe production, starting from a description of black holes and wormholes, in terms of the causal structure of spacetime, and following a qualitative review of the connection between vacuum…

General Relativity and Quantum Cosmology · Physics 2018-09-24 S. Ansoldi , Z. Merali , E. I. Guendelman

The general relativistic cosmological Friedmann equations which describe how the scale factor of the universe evolves are expanded explicitly to include energy forms not usually seen. The evolution of the universe as predicted by the…

Astrophysics · Physics 2008-11-26 Robert J. Nemiroff , Bijunath Patla

We investigate the minimal conditions under which the creation of our universe might arise due to a "bounce" from a previous collapse, rather than an explosion from a big-bang singularity. Such a bounce is sometimes referred to as a Tolman…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Carmen Molina-Paris , Matt Visser

We have already shown how a modified Friedmann equation, originating from a model of the Universe built from a certain $W_3$ algebra, is able to explainthe difference between the Hubble constants extracted from CMB data and from local…

General Relativity and Quantum Cosmology · Physics 2022-08-05 Jan Ambjorn , Yoshiyuki Watabiki

We describe a CDT-like model where breaking of W3 symmetry will lead to the emergence of time and subsequently of space. Surprisingly the simplest such models which lead to higher dimensional spacetimes are based on the four "magical"…

High Energy Physics - Theory · Physics 2017-04-11 J. Ambjorn , Y. Watabiki

Wormholes are non-trivial topological structures that arise as exact solutions to Einstein's field equations, theoretically connecting distinct regions of spacetime via a throat-like geometry. While static traversable wormholes necessarily…

General Relativity and Quantum Cosmology · Physics 2025-07-22 Mahdi Kord Zangeneh , Francisco S. N. Lobo

In a recent paper [arXiv:1206.4916] by T. Padmanabhan, it was argued that our universe provides an ideal setup to stress the issue that cosmic space is emergent as cosmic time progresses and that the expansion of the universe is due to the…

General Relativity and Quantum Cosmology · Physics 2012-11-09 Rong-Gen Cai
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