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Loop quantum cosmology homogeneous models with a massless scalar field show that the big-bang singularity can be replaced by a big quantum bounce. To gain further insight on the nature of this bounce, we study the semi-discrete loop quantum…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Pablo Laguna

It is well known that a closed universe with a minimally coupled massive scalar field always collapses to a singularity unless the initial conditions are extremely fine tuned. We show that the corrections to the equations of motion for the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Parampreet Singh , Alexey Toporensky

Loop quantum cosmology predicts that, in simple models, the big bang singularity of classical general relativity is replaced by a quantum bounce. Because of the extreme physical conditions near the bounce, a natural question is whether the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Alejandro Corichi , Parampreet Singh

The absence of isotropic singularity in loop quantum cosmology can be understood in an effective classical description as the universe exhibiting a Big Bounce. We show that with scalar matter field, the big bounce is generic in the sense…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Ghanashyam Date , Golam Mortuza Hossain

We investigate the emergence of a quantum Big-Bounce in the context of an isotropic Universe, filled by a self-interacting scalar field, which plays the role of a physical clock. The bouncing cosmology is the result of a scattering process,…

General Relativity and Quantum Cosmology · Physics 2024-10-04 S. Lo Franco , G. Montani

The dynamics of an inhomogeneous universe is studied with the methods of Loop Quantum Cosmology as an example of the quantization of vacuum cosmological spacetimes containing gravitational waves (Gowdy spacetimes). The analysis performed at…

General Relativity and Quantum Cosmology · Physics 2010-02-17 David Brizuela , Guillermo A. Mena Marugan , Tomasz Pawlowski

Several examples are known where quantum gravity effects resolve the classical big bang singularity by a bounce. The most detailed analysis has probably occurred for loop quantum cosmology of isotropic models sourced by a free, massless…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Martin Bojowald

We investigate non-singular bounce and cyclic cosmological evolutions in a universe governed by the extended nonlinear massive gravity, in which the graviton mass is promoted to a scalar-field potential. The extra freedom of the theory can…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-05 Yi-Fu Cai , Caixia Gao , Emmanuel N. Saridakis

General relativity predicts a singularity in the beginning of the universe being called big bang. Recent developments in loop quantum cosmology avoid the singularity and the big bang is replaced by a big bounce. A classical theory of…

General Physics · Physics 2011-02-08 Walter Petry

In recent years, Loop Quantum Gravity has emerged as a solid candidate for a nonperturbative quantum theory of General Relativity. It is a background independent theory based on a description of the gravitational field in terms of…

General Relativity and Quantum Cosmology · Physics 2009-10-16 Guillermo A. Mena Marugan

We examine the nature of the cosmological Big Bounce transition within the loop geometry underlying loop quantum cosmology at classical and quantum levels. Our canonical quantization method is an alternative to the standard loop quantum…

General Relativity and Quantum Cosmology · Physics 2009-09-24 Przemyslaw Malkiewicz , Wlodzimierz Piechocki

Loop Quantum Gravity is a background independent, nonperturbative approach to the quantization of General Relativity. Its application to models of interest in cosmology and astrophysics, known as Loop Quantum Cosmology, has led to new and…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Guillermo A. Mena Marugan

The quantum bounce a priori connects several (semi)classical epochs of Universe evolution, however determining if and how well the semiclassicality is preserved in this transition is highly nontrivial. We review the present state of…

General Relativity and Quantum Cosmology · Physics 2016-08-03 Tomasz Pawłowski

In Loop Quantum Gravity mathematically rigorous models of full quantum gravity were proposed. In this paper we study a cosmological sector of one of the models describing quantum gravity with positive cosmological constant coupled to…

General Relativity and Quantum Cosmology · Physics 2022-11-09 Marcin Kisielowski

We analyse the classical and quantum dynamics of a Bianchi I model in the presence of a small negative cosmological constant characterizing its evolution in term of the dust-time dualism. We demonstrate that in a canonical metric approach,…

General Relativity and Quantum Cosmology · Physics 2016-09-02 Riccardo Moriconi , Giovanni Montani , Salvatore Capozziello

We analyze the canonical quantum dynamics of the isotropic Universe in a metric approach by adopting a self-interacting scalar field as relational time. When the potential term is absent we are able to associate the the expanding and…

General Relativity and Quantum Cosmology · Physics 2023-09-15 Eleonora Giovannetti , Fabio Maione , Giovanni Montani

The big bounce (BB) transition within a flat Friedmann-Robertson-Walker model is analyzed in the setting of loop geometry underlying the loop cosmology. We solve the constraint of the theory at the classical level to identify physical phase…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Piotr Dzierzak , Przemyslaw Malkiewicz , Wlodzimierz Piechocki

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 consider a dynamical system of phantom scalar field under exponential potential in background of loop quantum cosmology. In our analysis, there is neither stable node nor repeller unstable node but only two saddle points, hence no Big…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Daris Samart , Burin Gumjudpai

We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields. Focusing initially on the collective coordinates (minisuperspace) associated with homogeneous,…

High Energy Physics - Theory · Physics 2016-07-07 Steffen Gielen , Neil Turok
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