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There is a widespread belief that the classical small inhomogeneities which gave rise to all structures in the Universe through gravitational instability originated from primordial quantum cosmological fluctuations. However, this transition…

General Relativity and Quantum Cosmology · Physics 2012-04-06 Nelson Pinto-Neto , Grasiele Santos , Ward Struyve

In this paper, we study the classical limit and unitary evolution of quantum cosmology by applying the Weyl--Wigner--Groenewold--Moyal formalism of deformation quantization to quantum cosmology of a homogeneous and isotropic universe with…

General Relativity and Quantum Cosmology · Physics 2020-11-06 S. Jalalzadeh , M. Rashki , S. Abarghouei Nejad

We propose a simple scenario which explains why our Universe appears spatially flat, homogeneous and isotropic. We use the Einstein-Cartan-Kibble-Sciama (ECKS) theory of gravity which naturally extends general relativity to include the spin…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-20 Nikodem J. Poplawski

Observations indicate that the universe is effectively flat, but they do not rule out a closed universe. The role of positive curvature is negligible at late times, but can be crucial in the early universe. In particular, positive curvature…

General Relativity and Quantum Cosmology · Physics 2010-04-06 George Ellis , Roy Maartens

Universe structure emerges in the unreduced, complex-dynamical interaction process with the simplest initial configuration (two attracting homogeneous fields). The unreduced interaction analysis avoiding any perturbative model gives…

General Physics · Physics 2015-03-20 Andrei P. Kirilyuk

We find a Friedmann model with appropriate matter/energy density such that the solution of the Wheeler-DeWitt equation exactly corresponds to the classical evolution. The well-known problems in quantum cosmology disappear in the resulting…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Moncy V. John

We find a class of solutions for a homogeneous and isotropic universe in which the initially expanding universe stops expanding, experiences contraction, and then expands again (the "bounce"), in the framework of Einstein gravity with a…

General Relativity and Quantum Cosmology · Physics 2019-06-26 Hiroki Matsui , Fuminobu Takahashi , Takahiro Terada

The expansion of our universe, when followed backward in time, implies that it emerged from a phase of huge density, the big bang. These stages are so extreme that classical general relativity combined with matter theories is not able to…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald

We review the main results that have been obtained in quantum cosmology from the perspective of the de Broglie-Bohm quantum theory. As it is a dynamical theory of assumed objectively real trajectories in the configuration space of the…

General Relativity and Quantum Cosmology · Physics 2015-06-16 N. Pinto-Neto , J. C. Fabris

Assuming that Quantum Mechanics is universal and that it can be applied over all scales, then the Universe is allowed to be in a quantum superposition of states, where each of them can correspond to a different space-time geometry. How can…

General Relativity and Quantum Cosmology · Physics 2024-02-27 José Luis Gaona-Reyes , Lucía Menéndez-Pidal , Mir Faizal , Matteo Carlesso

The origin of negative pressure fluid (the dark energy) is investigated in the quantum model of the homogeneous, isotropic and closed universe filled with a uniform scalar field and a perfect fluid which defines a reference frame. The…

General Relativity and Quantum Cosmology · Physics 2008-12-19 V. E. Kuzmichev , V. V. Kuzmichev

In our previous paper \cite{8}, we proposed a cosmological model from the emergence of space, which possesses a significant character of evaluating the vacuum energy from the Hubble constant and the age of universe. And one problem of this…

General Relativity and Quantum Cosmology · Physics 2016-01-01 Zi-Liang Wang , Jian-Bo Deng

Combining intervals of ekpyrotic (ultra-slow) contraction with a (non-singular) classical bounce naturally leads to a novel cyclic theory of the universe in which the Hubble parameter, energy density and temperature oscillate periodically,…

General Relativity and Quantum Cosmology · Physics 2019-07-12 Anna Ijjas , Paul J. Steinhardt

We propose a new cosmological paradigm in which our observed expanding phase is originated from an initially large contracting Universe that subsequently experienced a bounce. This category of models, being geodesically complete, is…

General Relativity and Quantum Cosmology · Physics 2008-11-07 Patrick Peter , Nelson Pinto-Neto

Alternative scenarios to the Big Bang singularity have been subject of intense research for several decades by now. Most popular in this sense have been frameworks were such singularity is replaced by a bounce around some minimal…

General Relativity and Quantum Cosmology · Physics 2017-09-25 Emanuele Alesci , Gioele Botta , Francesco Cianfrani , Stefano Liberati

It is shown that isotropic cosmology in the Riemann-Cartan spacetime allows to solve the problem of cosmological singularity as well as the problems of invisible matter components - dark energy and dark matter. All cosmological models…

General Relativity and Quantum Cosmology · Physics 2011-02-04 A. V. Minkevich

A cosmological model describing the evolution of n Ricci-flat spaces (n>1) in the presence of 1-component perfect-fluid and minimally coupled scalar field is considered. When the pressures in all spaces are proportional to the density, the…

High Energy Physics - Theory · Physics 2009-09-25 V. D. Ivashchuk , V. N. Melnikov

How the time evolution which is typical for classical cosmology emerges from quantum cosmology? The answer is not trivial because the Wheeler-DeWitt equation is time independent. A framework associating the quantum Hamilton-Jacobi to the…

General Relativity and Quantum Cosmology · Physics 2017-04-26 M. Fathi , S. Jalalzadeh

Universe structure emerges in the unreduced, complex-dynamic interaction process with the simplest initial configuration (two attracting homogeneous fields, quant-ph/9902015). The unreduced interaction analysis gives intrinsically creative…

General Physics · Physics 2007-05-23 Andrei P. Kirilyuk

In a Friedmann-Robertson-Walker (FRW) space-time background we study the classical cosmological models in the context of recently proposed theory of nonlinear minimal massive bigravity. We show that in the presence of perfect fluid the…

General Relativity and Quantum Cosmology · Physics 2016-09-07 F. Darabi , M. Mousavi
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