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To explore the properties of space and initial singularities in the context of general relativity, where spacetime becomes poorly defined and no longer belongs to a regular manifold, we examine the evolution of the expansion of timelike…

General Relativity and Quantum Cosmology · Physics 2025-04-04 Abdel Nasser Tawfik , Azzah A. Alshehri , Antonio Pasqua

A cubic correction of $f(T)$ gravity, where $T$ is the teleparallel scalar torsion, is considered to describe gravity in spatially flat Friedmann-Robertson-Walker model. A scale factor permitting departure from inflation era has been…

General Physics · Physics 2015-11-06 G. G. L. Nashed , W. El Hanafy

It is first argued that radiation by a uniformly accelerated charge in flat space-time indicates the need for a unified geometric theory of gravity and electromagnetism. Such a theory, based on a metric-affine $U_4$ manifold, is constructed…

General Physics · Physics 2018-08-30 Partha Ghose

General (tele)parallel Relativity, G$_\parallel$R, is the relativistic completion of Einstein's theories of gravity. The focus of this article is the derivation of the homogeneous and isotropic solution in G$_\parallel$R. The…

General Relativity and Quantum Cosmology · Physics 2023-10-18 Débora Aguiar Gomes , Jose Beltrán Jiménez , Tomi S. Koivisto

A spherically symmetric comoving fluid solution of Einstein's equations is adapted for cosmological application by extending the geometry of standard FRW cosmology using a generalised curvature term. The resulting model retains many of the…

General Relativity and Quantum Cosmology · Physics 2009-09-15 Ron Wiltshire

We discuss new models of an `affine' theory of gravity in multidimensional space-times with symmetric connections. We use and develop ideas of Weyl, Eddington, and Einstein, in particular, Einstein's proposal to specify the space - time…

High Energy Physics - Theory · Physics 2010-11-12 A. T. Filippov

Any canonical quantum theory can be understood to arise from the compatibility of the statistical geometry of distinguishable observations with the canonical Poisson structure of Hamiltonian dynamics. This geometric perspective offers a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Vishnu Jejjala , Djordje Minic , Chia-Hsiung Tze

The discovery of cosmic acceleration has presented a unique challenge for cosmologists. As observational cosmology forges ahead, theorists have struggled to make sense of a standard model that requires extreme fine tuning. This challenge is…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Chanda Prescod-Weinstein , Niayesh Afshordi , Michael L. Balogh

The conditions for the existence and stability of cosmological power-law scaling solutions are established when the Einstein-Hilbert action is modified by the inclusion of a function of the Gauss-Bonnet curvature invariant. The general form…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Kotub Uddin , James E. Lidsey , Reza Tavakol

We describe what cosmology looks like in the context of the geometric theory of gravity (GSG) based on a single scalar field. There are two distinct classes of cosmological solutions. An interesting feature is the possibility of having a…

General Relativity and Quantum Cosmology · Physics 2015-02-17 E. Bittencourt , U. Moschella , M. Novello , J. D. Toniato

Based on the distinction between the covariant and contravariant metric tensor components in the framework of the affine geometry approach and also on the choice of the contravariant components, it was shown that a wide variety of third,…

Mathematical Physics · Physics 2009-11-06 Bogdan G. Dimitrov

This thesis investigates the characteristics of modified teleparallel gravity models that incorporate a scalar field and a trace of the energy-momentum tensor, with particular attention to their cosmological effects, especially regarding…

General Relativity and Quantum Cosmology · Physics 2025-10-06 L K Duchaniya

Scalar-tensor gravitational theories are important extensions of standard general relativity, which can explain both the initial inflationary evolution, as well as the late accelerating expansion of the Universe. In the present paper we…

General Relativity and Quantum Cosmology · Physics 2017-06-28 J. A. Belinchón , T. Harko , M. K. Mak

The framework of a theory of gravity from the quantum to the classical regime is presented. The paradigm shift from full spacetime covariance to spatial diffeomorphism invariance, together with clean decomposition of the canonical…

General Relativity and Quantum Cosmology · Physics 2019-12-06 Chopin Soo , Hoi-Lai Yu

A theorem due to Bob Geroch and Pong Soo Jang ["Motion of a Body in General Relativity." Journal of Mathematical Physics 16(1), (1975)] provides a sense in which the geodesic principle has the status of a theorem in General Relativity (GR).…

History and Philosophy of Physics · Physics 2011-06-14 James Owen Weatherall

A shift-symmetric Galileon model in presence of spacetime torsion has been constructed for the first time. This has been realized by localizing (or, gauging) the Galileon symmetry in flat spacetime in an appropriate manner. We have applied…

General Relativity and Quantum Cosmology · Physics 2018-10-09 Rabin Banerjee , Sumanta Chakraborty , Pradip Mukherjee

Hamilton-Jacobi theory provides a natural starting point for a covariant description of the gravitational field. Using a spatial gradient expansion, one may solve for the phase of the wavefunction by using a line-integral in superspace.…

Astrophysics · Physics 2007-05-23 D. S. Salopek

The role of global topology in the dynamics of the Universe is poorly understood. Along with observational programmes for determining the topology of the Universe, some small theoretical steps have recently been made. Heuristic…

General Physics · Physics 2015-06-03 Boudewijn F. Roukema

Along this review, we focus on the study of several properties of modified gravity theories, in particular on black-hole solutions and its comparison with those solutions in General Relativity, and on Friedmann-Lemaitre-Robertson-Walker…

General Relativity and Quantum Cosmology · Physics 2015-06-05 A. de la Cruz-Dombriz , D. Saez-Gomez

A version of the cosmological perturbation theory in general relativity (GR) is developed, where the cosmological scale factor is identified with spatial averaging of the metric determinant logarithm and the cosmic evolution acquires the…

General Relativity and Quantum Cosmology · Physics 2011-07-19 B. M. Barbashov , V. N. Pervushin , A. F. Zakharov , V. A. Zinchuk