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We investigate a coupled system consisting of a complex scalar field, a U(1) gauge field, a complex Higgs scalar field, and Einstein gravity. We present nontopological soliton star solutions in which the interior geometry is described by…

High Energy Physics - Theory · Physics 2024-09-25 Tatsuya Ogawa , Hideki Ishihara

The dynamics of the torsion field is analyzed in the framework of the Covariant Canonical Gauge Theory of Gravity (CCGG), a De~Donder-Weyl Hamiltonian formulation of gauge gravity. The action is quadratic in both, the torsion and the…

General Relativity and Quantum Cosmology · Physics 2024-05-29 Vladimir Denk , David Vasak , Johannes Kirsch

We construct a gravastar configuration within the Shtanov-Sahni (SS) braneworld scenario, characterized by a timelike extra dimension and negative brane tension. Unlike classical black holes, which inevitably culminate in central curvature…

General Relativity and Quantum Cosmology · Physics 2026-03-25 Shounak Ghosh , Rikpratik Sengupta , Kazuharu Bamba

The manifesto of the current article is to investigate the compact anisotropic matter profiles in the context of one of the modified gravitational theories, known as $f(\mathcal{R}, \mathcal{T})$ gravity, where $\mathcal{R}$ is a Ricci…

General Relativity and Quantum Cosmology · Physics 2021-01-05 G. Mustafa , Xia Tie-Cheng , Mushtaq Ahmad , M. Farasat Shamir

We use a modified Einstein-Maxwell gravity to study stability of an electrostatic spherical star. Correction terms in this model are scalers which are made from contraction of Ricci tensor and electromagnetic vector potential. Our…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Hossein Ghaffarnejad , Tohid Ghorbani , Firoozeh Eidizadeh

The present work is to introduce a new kind of modified gravitational theory, named as $f(\mathcal{R,G,T})$ (also $f(\mathcal{R,T,G})$) gravity, where $\mathcal{R}$ is the Ricci scalar, $\mathcal{G}$ is Gauss-Bonnet invariant and…

General Relativity and Quantum Cosmology · Physics 2021-11-16 M. Ilyas

In this paper, we are interested to explore stable configurations of $d$-dimensional gravastars constructed from the interior $d$-dimensional de Sitter and exterior $d$-dimensional Schwarzschild/Reissner-Nordstr\"om (de Sitter) black holes…

General Relativity and Quantum Cosmology · Physics 2022-05-10 M. Sharif , Faisal Javed

The main purpose of this paper is to investigates structure scalars in the context of $f(\mathcal{G}, T)$ gravity, where $\mathcal{G}$ is the Gauss-Bonnet invariant and $T$ is the trace of stress energy tensor. For this aim, we have…

General Relativity and Quantum Cosmology · Physics 2018-04-05 M. Farasat Shamir , M. Awais Sadiq

This is an introduction to an algebraic construction of a gravity theory on noncommutative spaces which is based on a deformed algebra of (infinitesimal) diffeomorphisms. We start with some fundamental ideas and concepts of noncommutative…

High Energy Physics - Theory · Physics 2007-05-23 Frank Meyer

Rastall gravity is a generalization of the Einstein gravity in which the matter is not conserved in the presence of a non-constant spacetime curvature. In this report, we analyze Rastall gravity using the linearized formalism. The…

General Relativity and Quantum Cosmology · Physics 2025-05-12 Yuwadee Tongkong

We investigate scalar-tensor theories where matter couples to the scalar field via a kinetically dependent conformal coupling. These models can be seen as the low-energy description of invariant field theories under a global Abelian…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-29 Philippe Brax , Patrick Valageas

We investigate various anisotropic spherical distributions of charged celestial bodies within the context of f(R) gravity, where R represents the Ricci scalar. The properties of specific charged compact objects are analyzed by using the…

General Relativity and Quantum Cosmology · Physics 2025-05-13 W. U. Rahman , M. Ilyas , Yi Zhong , De-Liang Yao

In this Letter we construct the noncommutative (NC) gravity model on the $\theta$-constant NC space-time. We start from the NC $SO(2,3)_\star$ gauge theory and use the enveloping algebra approach and the Seiberg-Witten map to construct the…

High Energy Physics - Theory · Physics 2017-08-02 Marija Dimitrijevic Ciric , Biljana Nikolic , Voja Radovanovic

The properties of a star with constant positive energy density inside (as for the Schwarzschild interior geometry) and a negative pressure are investigated, using a static conformally flat spacetime. Because of the negative pressure, the…

General Relativity and Quantum Cosmology · Physics 2025-04-08 Hristu Culetu

We discuss some of the key topological aspects of a two $(1+1)$-dimensional (2D) self-interacting non-Abelian gauge theory (having no interaction with matter fields) in the framework of {\it chiral} superfield formalism. We provide the…

High Energy Physics - Theory · Physics 2008-11-26 R. P. Malik

We study plane-fronted electrovacuum waves in metric-affine gravity theories (MAG) with cosmological constant. Their field strengths are, on the gravitational side, curvature $R_{\alpha}{}^{\beta}$, nonmetricity $Q_{\alpha\beta}$, torsion…

General Relativity and Quantum Cosmology · Physics 2009-04-03 Alberto Garcia , Alfredo Macias , Dirk Puetzfeld , Jose Socorro

It was recently found that, when linearised in the absence of matter, 58 cases of the general gravitational theory with quadratic curvature and torsion are (i) free from ghosts and tachyons and (ii) power-counting renormalisable. We inspect…

General Relativity and Quantum Cosmology · Physics 2021-10-13 W. E. V. Barker , A. N. Lasenby , M. P. Hobson , W. J. Handley

We build extended sources for the Reissner-Nordstr\"{o}m metric. Our models describe a neutral perfect fluid core bounded by a charged thin shell, and feature everywhere positive rest mass density and everywhere non-negative active…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Victor Varela

In this study, we explore the thermodynamic aspects of a modified version of Rastall's gravity theory and its implications for cosmological scenarios. We analyze the role of non-conserved energy-momentum tensor equations and investigate…

General Relativity and Quantum Cosmology · Physics 2025-12-01 José A. C. Nogales , K. Luz-Burgoa , Laysa G. Martins

One of the very small number of serious alternatives to the usual concept of an astrophysical black hole is the "gravastar" model developed by Mazur and Mottola; and a related phase-transition model due to Laughlin et al. We consider a…

General Relativity and Quantum Cosmology · Physics 2009-04-17 Celine Cattoen , Tristan Faber , Matt Visser