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We obtain an approximate global stationary and axisymmetric solution of Einstein's equations which can be thought as a simple two layers star model: a self-gravitating ball built up by two layers of perfect fluid having different linear…

General Relativity and Quantum Cosmology · Physics 2018-06-12 Alfred Molina , Eduardo Ruiz

We discuss smooth metric measure spaces admitting two weighted Einstein representatives of the same weighted conformal class. First, we describe the local geometries of such manifolds in terms of certain Einstein and quasi-Einstein warped…

Differential Geometry · Mathematics 2025-04-11 Miguel Brozos-Vázquez , Eduardo García-Río , Diego Mojón-Álvarez

Recent advances in nuclear theory combined with new astrophysical observations have led to the need for specific theoretical models that actually apply to phenomena on dense-matter physics. At the same time, quantum chromodynamics (QCD)…

General Relativity and Quantum Cosmology · Physics 2022-08-30 Juan M. Z. Pretel , Takol Tangphati , Ayan Banerjee , Anirudh Pradhan

In this paper, we have presented a compact object model in the framework of Einstein-Gauss-Bonnet gravity (EGB) with a linear equation of state considering a metric potential proposed for Buchdahl (1959). The new obtained models satisfy all…

General Relativity and Quantum Cosmology · Physics 2023-01-24 Manuel Malaver , Rajan Iyer , Israr Khan

The interest in studying relativistic compact objects play an important role in modern astrophysics with an aim to understand several astrophysical issues. It is therefore natural to ask for internal structure and physical properties of…

General Physics · Physics 2018-09-19 S. K. Maurya , Ayan Banerjee , Y. K. Gupta

We study compactifications of Einstein gravity on product spaces in vacuum and their acceleration phases. Scalar potentials for the dimensionally reduced effective theory are found to be of exponential form and exact solutions are obtained…

High Energy Physics - Theory · Physics 2009-11-10 Chiang-Mei Chen , Pei-Ming Ho , Ishwaree P. Neupane , John E. Wang

We explore an interior solution of a physically symmetric vierbein with two unknown functions in conformal teleparallel gravity. The field equations can be described in a closed system for a particular form of the metric potentials and an…

General Relativity and Quantum Cosmology · Physics 2022-09-01 G. G. L. Nashed , K. Bamba

A broad class of generalized Einstein's gravity can be cast into Einstein's gravity with a minimally coupled scalar field using suitable conformal rescaling of the metric. Using this conformal equivalence between the theories, we derive the…

General Relativity and Quantum Cosmology · Physics 2011-09-30 J. Hwang

Higher-order gravity models have been recently the subject of much attention in the context of cosmic acceleration. These models are derived by adding various curvature invariants to the Einstein-Hilbert action. Several studies showed that…

Astrophysics · Physics 2014-11-18 Mustapha Ishak , Jacob Moldenhauer

We numerically construct compact stars in the scalar-tensor theory of gravity with non-minimal derivative coupling of a scalar field to the curvature and nonzero cosmological constant. There are two free parameters in this model of gravity:…

General Relativity and Quantum Cosmology · Physics 2025-04-08 P. E. Kashargin , A. A. Lebedev , S. V. Sushkov

We study a numerical solution to Einstein's equation for a compact object composed of null particles. The solution avoids quantum scale regimes and hence neither relies upon nor ignores the interaction of quantum mechanics and gravitation.…

General Relativity and Quantum Cosmology · Physics 2016-03-22 Dean P. Foster , John Langford , Gabe Perez-Giz

I discuss the conformal approach to the numerical simulation of radiating isolated systems in general relativity. The method is based on conformal compactification and a reformulation of the Einstein equations in terms of rescaled…

General Relativity and Quantum Cosmology · Physics 2022-09-21 Sascha Husa

In present paper a new compact star model in f(R,T) gravity is obtained where R and T denote the Ricci scalar and the trace of energy-momentum tensor $T_{\mu \nu}$ respectively. To develop the model we consider the spherically symmetric…

General Relativity and Quantum Cosmology · Physics 2021-06-01 Piyali Bhar

We study gravitational lensing by compact objects in gravity theories that can be written in a Post-Post-Newtonian (PPN) framework: i.e., the metric is static and spherically symmetric, and can be written as a Taylor series in m/r, where m…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Charles R. Keeton , A. O. Petters

We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken…

High Energy Physics - Theory · Physics 2011-04-20 C. Adam , N. Grandi , P. Klimas , J. Sanchez-Guillen , A. Wereszczynski

Metric $f(R)$ gravity theories are conformally equivalent to models of quintessence in which matter is coupled to dark energy. We derive a condition for stable tracker solution for metric $f(R)$ gravity in the Einstein frame. We find that…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Mahmood Roshan , Fatimah Shojai

We consider a model involving a self-interacting complex scalar field minimally coupled to gravity and emphasize the cylindrically symmetric classical solutions. A general ansatz is performed which transforms the field equations into a…

General Relativity and Quantum Cosmology · Physics 2013-07-11 Y. Brihaye , T. Delsate

Alternative gravity theory is currently an incredibly significant technique for addressing some enduring experimental difficulties, such as the universe's dark region. They may also be employed in celestial cosmology, producing results that…

General Relativity and Quantum Cosmology · Physics 2024-05-01 Tayyaba Naz , Adnan Malik , Zenab Ramay

We investigate the metric perturbations of the restricted f(R) theory of gravity in the cosmological context and explore the phenomenological implications of this model. We show that it is possible to construct a restricted model of…

General Relativity and Quantum Cosmology · Physics 2017-04-12 M. Chaichian , A. Ghalee , J. Kluson

Recent works by the second author and Maxwell et al. have shown that the Einstein-scalar field conformal constraint equations are highly complex and generally intractable, even in the vacuum case. In this article, to gain a clearer…

General Relativity and Quantum Cosmology · Physics 2026-03-11 Philippe Castillon , Cang Nguyen-The
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