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The novel idea is that the undergoing accelerated expansion of the universe happens due to infrared quantum gravity modifications at intermediate astrophysical scales of galaxies or galaxy clusters, within the framework of Asymptotically…

General Relativity and Quantum Cosmology · Physics 2021-02-16 Fotios K. Anagnostopoulos , Georgios Kofinas , Vasilios Zarikas

We consider spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) solutions of Milgrom's recently proposed class of bimetric theories of gravity. These theories have two different regimes, corresponding to high and low…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Timothy Clifton , Thomas G. Zlosnik

We derive the quantum energy-momentum tensor and the corresponding quantum equation of state for gauge field theory using the effective Lagrangian approach. The energy-momentum tensor has a term proportional to the space-time metric and…

High Energy Physics - Theory · Physics 2022-01-05 George Savvidy

Alternative cosmological models have been under deep scrutiny in recent years, aiming to address the main shortcomings of the $\Lambda$CDM model. Moreover, as the accuracy of cosmological surveys improved, new tensions have risen between…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-05 Filippo Bouchè , Salvatore Capozziello , Vincenzo Salzano

An overview is given of the current status of the theory and observations of the acceleration of the expansion of the observable part of the Universe. Contents 1. Historical Introduction 2. Friedmann equations and cosmological acceleration…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-16 Sergei I. Blinnikov , Alexander D. Dolgov

We study a cosmological model based on the canonical Hamiltonian transformation theory. Using a linear-quadratic approach for the free gravitational De Donder-Weyl Hamiltonian $H_\mathrm{Gr}$, the model contains terms describing a…

General Relativity and Quantum Cosmology · Physics 2023-06-07 Johannes Kirsch , David Vasak , Armin van de Venn , Jürgen Struckmeier

In order to explain the late-time cosmological acceleration, we propose a new pure geometric gravity based on Deser-Woodard theory, in which the expansion of a matter-dominated universe can be accelerating. This new theory behaves as well…

General Relativity and Quantum Cosmology · Physics 2018-10-31 Shuxun Tian

We present the detailed derivation of the recently announced most general cosmological solution with homogeneous and isotropic metric in the ghost-free massive gravity theory. We use the standard parametrization of the theory in terms of…

High Energy Physics - Theory · Physics 2013-05-30 Mikhail S. Volkov

The Wheeler-DeWitt equation is solved for some scalar-tensor theories of gravitation in the case of homogeneous and isotropic cosmological models.We present general solutions corresponding to cosmological term: (i)\lambda(\phi)=0$ and $(ii)…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Luis O. Pimentel , César Mora

The late time acceleration of the Universe has challenged contemporary cosmology since its discovery. General Relativity explains this phenomenon by introducing the cosmological constant, named the standard cosmological model…

General Relativity and Quantum Cosmology · Physics 2024-01-02 Simran Arora

The Nobel Prize winning confirmation in 1998 of the accelerated expansion of our Universe put into sharp focus the need of a consistent theoretical model to explain the origin of this acceleration. As a result over the past two decades…

General Relativity and Quantum Cosmology · Physics 2018-12-07 Sebastian Bahamonde , Christian G. Boehmer , Sante Carloni , Edmund J. Copeland , Wei Fang , Nicola Tamanini

It is shown that all torsion-free vacuum solutions of the model of dS gauge theory of gravity are the vacuum solutions of Einstein field equations with the same positive cosmological constant. Furthermore, for the gravitational theories…

General Relativity and Quantum Cosmology · Physics 2009-10-02 Chao-Guang Huang , Meng-Sen Ma

Recently, inhomogeneous generalisations of the Friedmann-Lemaitre-Robertson-Walker cosmological models have gained interest in the astrophysical community and are more often employed to study cosmological phenomena. However, in many papers…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-17 Krzysztof Bolejko , Marie-Noëlle Célérier , Andrzej Krasiński

The accelerating expansion of the Universe poses a major challenge to our understanding of fundamental physics. One promising avenue is to modify general relativity and obtain a new description of the gravitational force. Because…

General Relativity and Quantum Cosmology · Physics 2015-08-28 Adam R. Solomon

This article deals with a nonrelativistic cosmological model based on Galilean covariance, formulated within a five-dimensional Galilean manifold. Within this framework, we construct an isotropic and homogeneous metric analogous to the…

General Relativity and Quantum Cosmology · Physics 2025-11-17 R. G. G. Amorim , A. F. Santos , K. V. S. Araújo , S. C. Ulhoa

We establish a new model, which takes into account a dynamic (inertial) self-interaction of gravitating systems. The model is formulated by introduction of a new function depending on the square of the covariant derivative of the velocity…

General Relativity and Quantum Cosmology · Physics 2009-12-17 A. B. Balakin , H. Dehnen

It is proved that in order to obtain a model of the accelerated cosmic expansion the thing one only need to do is to add a perturbation term to the Einstein-Hilbert Lagrangian. This term leads to some symmetry breaking terms in the fields…

General Relativity and Quantum Cosmology · Physics 2013-01-22 G. Y. Chee

In this paper, we construct and study solutions of Einstein's equations in vacuum with a positive cosmological constant which can be considered as inhomogeneous generalizations of the Nariai cosmological model. Similar to this Nariai…

General Relativity and Quantum Cosmology · Physics 2017-07-12 Florian Beyer , Leon Escobar , Jörg Frauendiener

The Klein-Gordon equations were recently solved in general relativity for the case of a plane-symmetric static massless scalar field with cosmological constant. By analytic continuation, time-dependent solutions can be obtained that…

General Relativity and Quantum Cosmology · Physics 2009-04-22 Chris Vuille , Jocelyn Dunn

A scale invariant, Weyl geometric, Lagrangian approach to cosmology is explored, with a a scalar field phi of (scale) weight -1 as a crucial ingredient besides classical matter \cite{Tann:Diss,Drechsler:Higgs}. For a particularly simple…

Astrophysics · Physics 2009-11-18 Erhard Scholz