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Related papers: $f(Q,L_m)$ gravity, and its cosmological implicati…

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We consider the symmetric teleparallel $f\left( Q\right) $-gravity in Friedmann--Lema\^{\i}tre--Robertson--Walker cosmology with nonzero spatial curvature. For a nonlinear $f\left( Q\right) $ model there exist always the limit of General\…

General Relativity and Quantum Cosmology · Physics 2023-10-09 Andronikos Paliathanasis

The quantum field theory of gravitation is constructed in terms of Lagrangian density of Dirac fields which couple to the electromagnetic field $A_\mu$ as well as the gravitational field $\cal G$. The gravity appears in the mass term as $…

General Physics · Physics 2008-04-17 Takehisa Fujita

The superstring and superbrane theories which include gravity as a necessary and fundamental part renew an interest to alternative representations of general relativity as well as the alternative models of gravity. We study the coframe…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Yakov Itin

It has been shown that at the semi-classical order, gravitational theories with quantum fluctuations can be effectively recast as modified theories of gravity with non-minimal gravity-matter couplings. We proceed from an observational…

General Relativity and Quantum Cosmology · Physics 2022-04-29 Reginald Christian Bernardo , Che-Yu Chen , Jackson Levi Said , Yu-Hsien Kung

As a classical approach, the dynamics of the Universe, influenced by its dark components, are unveiled through prior modifications of Einstein's equations. Cosmography, on the other hand, is a highly efficient tool for reconstructing any…

General Relativity and Quantum Cosmology · Physics 2024-07-19 Sai Swagat Mishra , N. S. Kavya , P. K. Sahoo , V. Venkatesha

Modified theories of gravity have been invoked recently as an alternative to dark energy, in an attempt to explain the apparent accelerated expansion of the universe at the present time. In order to describe inhomogeneities in cosmological…

General Relativity and Quantum Cosmology · Physics 2016-04-15 Adam J. Christopherson

Generalised Teleparallel gravity, also referred to as f(T) gravity, has been recently proposed as an extended theory of gravitation able to give rise to an accelerated expansion in a matter only universe. The cosmic speed up is driven by an…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Vincenzo F. Cardone , Ninfa Radicella , Stefano Camera

We study flat Friedmann-Lemaitre-Robertson-Walker cosmological models for a scalar field coupled nonminimally to teleparallel gravity with generic coupling and potential functions. The goal of this paper is to determine the conditions under…

General Relativity and Quantum Cosmology · Physics 2016-08-08 Laur Jarv , Alexey Toporensky

I consider theories of gravity built not just from the metric and affine connection, but also other (possibly higher rank) symmetric tensor(s). The Lagrangian densities are scalars built from them, and the volume forms are related to…

High Energy Physics - Theory · Physics 2020-04-06 Chethan Krishnan

In the present manuscript, I examine an intriguing relation at the classical level between general relativity and a theory where matter couples uniquely multiplicatively to geometry in the Lagrangian density. Interestingly, the…

General Relativity and Quantum Cosmology · Physics 2018-12-20 Olivier Minazzoli

We propose a cosmological model in the framework of the Poincar\'e gauge theory of gravity (PG). The gravitational Lagrangian is quadratic in curvature and torsion. In our specific model, the Lagrangian contains (i) the curvature scalar $R$…

General Relativity and Quantum Cosmology · Physics 2011-02-25 Peter Baekler , Friedrich W. Hehl , James M. Nester

In the present article we analyze the matter-geometry coupled $f(Q,T)$ theory of gravity. We offer the fully covariant formulation of the theory, with which we construct the correct energy balance equation and employ it to conduct a…

General Relativity and Quantum Cosmology · Physics 2023-03-30 Tee-How Loo , Raja Solanki , Avik De , P. K. Sahoo

Two approaches to the study of cosmological density perturbations in modified theories of Palatini gravity have recently been discussed. These utilise, respectively, a generalisation of Birkhoff's theorem and a direct linearization of the…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Kotub Uddin , James E Lidsey , Reza Tavakol

Teleparallel gravity offers a new avenue in which to construct gravitational models beyond general relativity. While teleparallel gravity can be framed in a way to be dynamically equivalent to general relativity, its modifications are…

General Relativity and Quantum Cosmology · Physics 2021-01-28 Sebastian Bahamonde , Viktor Gakis , Stella Kiorpelidi , Tomi Koivisto , Jackson Levi Said , Emmanuel N. Saridakis

We explore the role of the affine connection in $f(Q)$ gravity, a modified theory where gravity is governed by non-metricity within the symmetric teleparallel framework. Although the connection is constrained to be flat and torsionless, it…

General Relativity and Quantum Cosmology · Physics 2025-11-27 Ismael Ayuso , Mariam Bouhmadi-López , Che-Yu Chen , Xiao Yan Chew , Konstantinos Dialektopoulos , Yen Chin Ong

The relationship between the metric and nonrelativistic matter distribution depends on the theory of gravity and additional fields, providing a possible way of distinguishing competing theories. With the assumption that the geometry and…

Astrophysics · Physics 2008-10-28 Mustafa A. Amin , Robert V. Wagoner , Roger D. Blandford

$f(Q)$ gravity is an extension of the symmetric teleparallel equivalent to general relativity. We demonstrate the Hamiltonian analysis of $f(Q)$ gravity with fixing the coincident gauge condition. Using the standard Dirac-Bergmann…

General Relativity and Quantum Cosmology · Physics 2022-08-12 Kun Hu , Taishi Katsuragawa , Taotao Qiu

Standard cosmological models rely on an approximate treatment of gravity, utilizing solutions of the linearized Einstein equations as well as physical approximations. In an era of precision cosmology, we should ask: are these approximate…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-06 John T. Giblin , James B. Mertens , Glenn D. Starkman , Chi Tian

After recalling the differential geometry of non-metric connections in the formalism of differential forms, we introduce the idea of a Non-Metricity (NM) connection, whose connection $1$--forms coincides with the non-metricity $1$--forms…

General Relativity and Quantum Cosmology · Physics 2020-09-04 Igor Mol

In this article, we study the expanding nature of universe in the contest of $f(R,L_m)$ gravity theory, here $ R $ represents the Ricci scalar and $ L_m $ is the matter Lagrangian density. With a specific form of $ f(R,L_m) $, we obtain the…

General Relativity and Quantum Cosmology · Physics 2023-06-28 J. K. Singh , Shaily , Ratbay Myrzakulov , Harshna Balhara
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