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We perform a study of the gravitating electrostatic spherically symmetric (G-ESS) solutions of Einstein field equations minimally coupled to generalized non-linear abelian gauge models in three space dimensions. These models are defined by…

High Energy Physics - Theory · Physics 2010-04-29 J. Diaz-Alonso , D. Rubiera-Garcia

This study explores the behavior of compact stars within the framework of $f(R,L_m,T)$ gravity, focusing on the functional form $f(R,L_m,T) = R + \alpha TL_m$. The modified Tolman-Oppenheimer-Volkoff (TOV) equations are derived and…

General Relativity and Quantum Cosmology · Physics 2024-07-09 Clésio E. Mota , Juan M. Z. Pretel , César O. V. Flores

In general relativity with vector and scalar fields given by the Lagrangian ${\cal L}(F,\phi,X)$, where $F$ is a Maxwell term and $X$ is a kinetic term of the scalar field $\phi$, we study the linear stability of static and spherically…

General Relativity and Quantum Cosmology · Physics 2025-12-18 Antonio De Felice , Shinji Tsujikawa

In the Palatini action of general relativity the connection and the metric are treated as independent dynamical variables. Instead of assuming a relation between these quantities, the desired relation between them is derived through the…

General Relativity and Quantum Cosmology · Physics 2009-11-05 Eran Rosenthal

We generalize previous work by considering a novel gravitational model with an action given by an arbitrary function of the Ricci scalar, the matter Lagrangian density, a scalar field and a kinetic term constructed from the gradients of the…

General Relativity and Quantum Cosmology · Physics 2013-02-06 Tiberiu Harko , Francisco S. N. Lobo , Olivier Minazzoli

We present a new formulation for numerically obtaining axisymmetric equilibrium structures of rotating stars in two spatial dimensions. With a view to apply it to the secular evolution of rotating stars, we base it on the Lagrangian…

Solar and Stellar Astrophysics · Physics 2023-03-15 Misa Ogata , Hirotada Okawa , Kotaro Fujisawa , Nobutoshi Yasutake , Yu Yamamoto , Shoichi Yamada

Effective loop quantum gravity dynamics are derived for spherically symmetric spacetimes with a perfect fluid matter content. For homogeneous spacetimes, the effective dynamics agree with the standard results of loop quantum cosmology,…

General Relativity and Quantum Cosmology · Physics 2025-03-04 Edward Wilson-Ewing

Teleparallel Gravity offers the possibility of reformulating gravity in terms of torsion by exchanging the Levi-Civita connection with the Weitzenb\"ock connection which describes torsion rather than curvature. Surprisingly, Teleparallel…

General Relativity and Quantum Cosmology · Physics 2020-07-23 Maria Caruana , Gabriel Farrugia , Jackson Levi Said

We develop a symmetric teleparallel gravity model in a space-time with only the non-metricity is nonzero, in terms of a Lagrangian quadratic in the non-metricity tensor. We present a detailed discussion of the variations that may be used…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Muzaffer Adak , Mestan Kalay , Ozcan Sert

We study nonlinear gravity theories in both the metric and the Palatini (metric-affine) formalisms. The nonlinear character of the gravity lagrangian in the metric formalism causes the appearance of a scalar source of matter in Einstein's…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Gonzalo J. Olmo , William Komp

We investigate the existence of static, spherically symmetric compact objects within the framework of symmetric teleparallel scalar-tensor gravity. This theory extends the Brans-Dicke and scalar-tensor models within the symmetric…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Grigorios Panotopoulos , Andrés Lueiza-Colipí , Nikolaos Dimakis , Andronikos Paliathanasis

We investigate in this paper the structures of neutron and quark stars in f(T) theory of gravity where T denotes the torsion scalar. Attention is attached to the TOV type equations of this theory and numerical integrations of these…

General Relativity and Quantum Cosmology · Physics 2016-11-29 A. V. Kpadonou , M. J. S. Houndjo , M. E. Rodrigues

We study modified theories of gravity of the f(R) type in Palatini formalism. We first consider the stability of atoms when the Palatini gravitational interaction is taken into account in the derivation of the non-relativistic Schrodinger…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Gonzalo J. Olmo

In this work, we study cosmological and astrophysical applications of the recently proposed generalized hybrid metric-Palatini gravity theory, which combines features of both the metric and the Palatini approaches to the variational method…

General Relativity and Quantum Cosmology · Physics 2019-11-20 João Luís Rosa

The novel proposal to invoke the split of the Ricci scalar into bulk and boundary terms in the gravitational action, opens up a new avenue of investigation into stellar dynamics. The Lagrangian contains functional forms of the bulk term…

General Relativity and Quantum Cosmology · Physics 2026-05-14 Sudan Hansraj , Christian G. Boehmer , Ndumiso Buthelezi

We investigate some fundamental features of a class of non-linear relativistic lagrangian field theories with kinetic self-coupling. We focus our attention upon theories admitting static, spherically symmetric solutions in three space…

High Energy Physics - Theory · Physics 2008-11-26 Joaquin Diaz-Alonso , Diego Rubiera-Garcia

We derive the dynamical equations for a non-local gravity model in the Palatini formalism and we discuss some of the properties of this model. We have shown that, in some specific cases, the vacuum solutions of general relativity are also…

General Relativity and Quantum Cosmology · Physics 2016-12-16 F. Briscese , M. L. Pucheu

We present a new formulation to construct numerically equilibrium configurations of rotating stars in general relativity. Having in mind the application to their quasi static evolutions, we adopt a Lagrangian formulation of our own…

General Relativity and Quantum Cosmology · Physics 2022-04-22 Hirotada Okawa , Kotaro Fujisawa , Nobutoshi Yasutake , Misa Ogata , Yu Yamamoto , Shoichi Yamada

We search for spherically symmetric solutions of f(R) theories of gravity via the Noether Symmetry Approach. A general formalism in the metric framework is developed considering a point-like f(R)-Lagrangian where spherical symmetry is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 S. Capozziello , A. Stabile , A. Troisi

We prove that a generalized Schwarzschild-like ansatz can be consistently employed to construct $d$-dimensional static vacuum black hole solutions in any metric theory of gravity for which the Lagrangian is a scalar invariant constructed…

General Relativity and Quantum Cosmology · Physics 2020-02-20 Sigbjørn Hervik , Marcello Ortaggio