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Related papers: Charged gravastar model in $f(T)$ gravity admittin…

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Multiple scalar fields appear in vast modern particle physics and gravity models. When they couple to gravity non-minimally, conformal transformation is utilized to bring the theory into Einstein frame. However, the kinetic terms of scalar…

General Relativity and Quantum Cosmology · Physics 2021-09-22 Yong Tang , Yue-Liang Wu

One of the main challenges in astronomy is the direct observation of black holes. However, differentiating them from black holes through photon observations can be difficult if Ultra-Compact Objects with unstable circular photon orbits…

General Relativity and Quantum Cosmology · Physics 2026-05-06 M. A. Anacleto , A. T. N. Silva , L. Casarini

We investigate the inflationary realization in the context of unimodular $F(T)$ gravity, which is based on the $F(T)$ modification of teleparallel gravity, in which one imposes the unimodular condition through the use of Lagrange…

General Relativity and Quantum Cosmology · Physics 2017-06-29 Kazuharu Bamba , Sergei D. Odintsov , Emmanuel N. Saridakis

We present new exact solutions for the Einstein-Maxwell system in static spherically symmetric interior spacetimes. For a particular form of the gravitational potentials and the electric field intensity, it is possible to integrate the…

General Relativity and Quantum Cosmology · Physics 2009-10-16 S. D. Maharaj , S. Thirukkanesh

A simple modification to Einstein's theory of gravity in terms of a non-Riemannian connection is examined. A new tensor-variational approach yields field equations that possess a covariance similar to the gauge covariance of…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Robin W Tucker , Charles Wang

We calculate static and spherically symmetric solutions for the Rastall modification of gravity to describe Neutron Stars (NS). The key feature of the Rastall gravity is the non-conservation of the energy-momentum tensor proportionally to…

General Relativity and Quantum Cosmology · Physics 2016-10-24 A. M. Oliveira , H. E. S. Velten , J. C. Fabris , L. Casarini

We analyze the construction of conformal theories of gravity in the realm of teleparallel theories. We first present a family of conformal theories which are quadratic in the torsion tensor and are constructed out of the tetrad field and of…

General Relativity and Quantum Cosmology · Physics 2012-01-19 J. W. Maluf , F. F. Faria

This paper discusses the configuration of gravitational vacuum star or gravastar with the impact of geometry and matter coupling present in $f(R,T)$ gravity. The gravastar is also conceptualized as a substitute for a black hole which is…

General Relativity and Quantum Cosmology · Physics 2020-12-07 M. Sharif , Arfa Waseem

We discuss the interior solutions of fluid Sphere in f(R,T) gravity admitting conformal killing vectors, where R is Ricci scalar and T is trace of energy momentum tensor. The solutions corresponding to isotropic and anisotropic…

General Relativity and Quantum Cosmology · Physics 2018-11-15 M. Zubair , I. H. Sardar , F. Rahaman , G. Abbas

We study the modified Reissner Nordstrom metric in the unimodular gravity. So far the spherical symmetric Einstein field equation in unimodular gravity has been studied in the absence of any source. We consider static electric and magnetic…

General Relativity and Quantum Cosmology · Physics 2017-07-26 Pankaj Chaturvedi , Naveen K. Singh , Dharm Veer Singh

We investigate static cylindrical solutions within an extended theory of modified gravity. By incorporating various coupling functions through a straightforward boost symmetry approach, we establish the equations of motion in a…

General Relativity and Quantum Cosmology · Physics 2024-07-31 Davood Momeni , Phongpichit Channuie , Mudhahir Al-Ajmi

We propose a model of gravity in which a General Relativity metric tensor and an effective metric generated from a single scalar formulated in Geometric Scalar Gravity are mixed. We show that the model yields the exact Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2016-10-12 Nahomi Kan , Takuya Maki , Kiyoshi Shiraishi

We consider a model of Bose-Einstein condensate of weakly interacting off-shell gravitons in the regime that is far from the quantum critical point. Working in static spherically symmetric setup, recent study has demonstrated that the…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Andy Octavian Latief , Fiki Taufik Akbar , Bobby Eka Gunara

It is well-known that $f(R)$ gravity models formulated in Einstein conformal frame are equivalent to Einstein gravity together with a minimally coupled scalar field. In this case, the scalar field couples with the matter sector and the…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Yousef Bisabr

Gravastars, theoretical alternatives to black holes, have captured the interest of scientists in astrophysics due to their unique properties. This paper aims to further investigate the exact solution of a novel gravastar model based on the…

General Relativity and Quantum Cosmology · Physics 2024-05-01 Faisal Javed , Ji Lin

We present a new formulation for the canonical approach to conformal (Weyl-squared) gravity and its extension by the Einstein-Hilbert term and a nonminimally coupled scalar field. For this purpose we use a unimodular decomposition of the…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Claus Kiefer , Branislav Nikolic

We explore the recently introduced modified Gauss-Bonnet gravity [1], $f(\mathcal{G},T)$ pragmatic with $\mathcal{G}$, the Gauss-Bonnet term, and ${T}$, the trace of the energy-momentum tensor. Noether symmetry approach has been used to…

General Physics · Physics 2017-01-31 M. Farasat Shamir , Mushtaq Ahmad

We consider f(R,T) modified theory of gravity, in which the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar and the trace of the energy-momentum tensor of the matter, in order to investigate the dark-matter…

General Relativity and Quantum Cosmology · Physics 2016-11-02 Raziyeh Zaregonbadi , Mehrdad Farhoudi , Nematollah Riazi

We extract exact charged black-hole solutions with flat transverse sections in the framework of D-dimensional Maxwell-f(T) gravity, and we analyze the singularities and horizons based on both torsion and curvature invariants. Interestingly…

High Energy Physics - Theory · Physics 2013-03-21 Salvatore Capozziello , P. A. Gonzalez , Emmanuel N. Saridakis , Yerko Vasquez

Consistency of Einstein's gravitational field equation $G_{\mu\nu} \propto T_{\mu\nu}$ imposes a "conservation condition" on the $T$-tensor that is satisfied by (i) matter stress tensors, as a consequence of the matter equations of motion,…

General Relativity and Quantum Cosmology · Physics 2015-12-09 Eric Bergshoeff , Wout Merbis , Alasdair J. Routh , Paul K. Townsend