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Rainbow gravity modifies general relativity by introducing an energy dependent metric, which is expected to have a role in the quantum theory of black holes and in quantum gravity at Planck energy scale. We show that rainbow gravity can be…

General Relativity and Quantum Cosmology · Physics 2018-06-07 Maria Chiara Braidotti , Claudio Conti

We extend our previous study on the effects of an information-theoretically motivated nonlinear correction to the Wheeler-deWitt equation in the minisuperspace scheme for FRW universes. Firstly we show that even when the geometry is…

General Relativity and Quantum Cosmology · Physics 2009-05-01 Le-Huy Nguyen , Rajesh R. Parwani

In this article, we examine the possibility that there exist special scalar-tensor theories of gravity with completely nonsingular FRW solutions. Our investigation in fact shows that while most probes living in such a Universe never see the…

High Energy Physics - Theory · Physics 2009-09-15 Nemanja Kaloper , Keith A. Olive

We investigate gravitational collapse of thick shell of fluid in the isotropic homogeneous universe without radiation described by the Einstein gravity with cosmological constant. We construct analytic solutions of this kind interpolating…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Shuichi Yokoyama

We investigated the cosmology in a higher-curvature gravity where the dimensionality of spacetime gives rise to only quantitative difference, contrary to Einstein gravity. We found exponential type solutions for flat isotropic and…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Y. Ezawa , H. Iwasaki , M. Ohmori , S. Ueda , N. Yamada , T. Yano

In the present work, we study the dynamical evolution of an homogeneous and anisotropic KS cosmological model, considering general relativity as the gravitational theory, such that there are three different perfect fluids in the matter…

General Relativity and Quantum Cosmology · Physics 2022-06-15 G. Oliveira-Neto , D. L. Canedo , G. A. Monerat

We consider a self-consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy. The perfect fluid is taken to be the one obeying the usual equation of state, i.e., $p = \zeta \ve$, with…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha

Loop quantum cosmology is an application of recent developments for a non-perturbative and background independent quantization of gravity to a cosmological setting. Characteristic properties of the quantization such as discreteness of…

Astrophysics · Physics 2009-11-13 Martin Bojowald

In a former paper we proposed a model for the quantization of gravity by working in a bundle $E$ where we realized the Hamilton constraint as the Wheeler-DeWitt equation. However, the corresponding operator only acts in the fibers and not…

General Relativity and Quantum Cosmology · Physics 2018-10-23 Claus Gerhardt

We investigate the quantum dynamics of the isotropic Universe in the presence of a free massless scalar field, playing the role of a physical clock. The Hilbert space is constructed via a direct analogy between the Wheeler-DeWitt equation…

General Relativity and Quantum Cosmology · Physics 2024-06-11 Gabriele Barca , Luisa Boglioni , Giovanni Montani

For the anisotropic Universe filled with massless vector field in the General Relativity frame we obtain bouncing solution for one of scale factors. We obtain the Universe with finite maximal energy density, finite value of…

High Energy Physics - Theory · Physics 2015-05-30 Michal Artymowski , Zygmunt Lalak

Our review is devoted to three promising research lines in quantum cosmology and the physics of the early universe. The nonperturbative renormalization programme is making encouraging progress that we here assess from the point of view of…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Giampiero Esposito

The problems encountered in trying to quantize the various cosmological models, are brought forward by means of a concrete example. The Automorphism groups are revealed as the key element through which G.C.T.'s can be used for a general…

General Relativity and Quantum Cosmology · Physics 2011-07-19 T. Christodoulakis

We explicitly compute the dynamics of closed homogeneous and isotropic universes permeated by a single perfect fluid with a constant equation of state parameter $w$ in the context of a recent reformulation of general relativity, proposed in…

General Relativity and Quantum Cosmology · Physics 2015-05-06 P. P. Avelino

In the background of homogeneous and isotropic flat FLRW space-time, both classical and quantum cosmology has been studied for teleparallel dark energy (DE) model. Using Noether symmetry analysis, not only the symmetry vector but also the…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Dipankar Laya , Roshni Bhaumik , Sourav Dutta , Subenoy Chakraborty

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

Classical models for dark energy can exhibit a variety of singularities, many of which occur for scale factors much bigger than the Planck length. We address here the issue whether some of these singularities, the big freeze and the big…

General Relativity and Quantum Cosmology · Physics 2009-07-09 Mariam Bouhmadi-Lopez , Claus Kiefer , Barbara Sandhoefer , Paulo Vargas Moniz

This talk is about solving cosmological equations analytically without approximations, and discovering new phenomena that could not be noticed with approximate solutions. We found all the solutions of the Friedmann equations for a specific…

General Relativity and Quantum Cosmology · Physics 2011-09-30 Itzhak Bars

In metric-affine gravity, both the gravitational and matter actions depend not just on the metric, but also on the independent affine connection. Thus matter can be modeled as a hyperfluid, characterized by both the energy-momentum and…

General Relativity and Quantum Cosmology · Physics 2025-03-25 Ilaria Andrei , Damianos Iosifidis , Laur Järv , Margus Saal

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