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Related papers: New Numerical Algorithm for Modeling of Boson-Ferm…

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We present solutions for non-spherically symmetric neutron stars. We begin by deriving the Tolman-Oppenheimer-Volkoff equations from a parameterized metric that takes into account the deformation of the star due to differences in equatorial…

General Relativity and Quantum Cosmology · Physics 2024-03-01 J. T. Quartuccio , P. H. R. S. Moraes , J. D. V. Arbañil

In a series of articles we describe a novel class of geometrical models of relativistic stars. Our approach to the static spherically symmetric solutions of Einstein equations is based on a careful physical analysis of radial gauge…

Astrophysics · Physics 2007-05-23 P. P. Fiziev

Assuming static and spherically symmetric stars with perfect fluid matter, we used realistic equations of state to study neutron stars in covariant $f(Q)$ gravity. The structure profiles and properties of neutron stars such as mass, radius…

General Relativity and Quantum Cosmology · Physics 2024-09-05 Muhammad Azzam Alwan , Tomohiro Inagaki , B. Mishra , S. A. Narawade

Numerous tabletop experiments have been dedicated to exploring the manifestations of screened scalar field dark energy, such as symmetron or chameleon fields. Precise theoretical predictions require simulating field configurations within…

High Energy Physics - Phenomenology · Physics 2024-01-30 Hauke Fischer , René I. P. Sedmik

In the version \cite{Fiziev14} of this paper we presented for the first time the basic equations and relations for relativistic static spherically symmetric stars (SSSS) in the model of minimal dilatonic gravity (MDG). This model is {\em…

General Relativity and Quantum Cosmology · Physics 2017-08-14 Plamen P Fiziev

We study the stability of rotating scalar boson stars, comparing those made from a simple massive complex scalar (referred to as mini boson stars), to those with several different types of nonlinear interactions. To that end, we numerically…

General Relativity and Quantum Cosmology · Physics 2021-02-16 Nils Siemonsen , William E. East

We investigate BBN in scalar-tensor theories of gravity with arbitrary matter couplings and self-interaction potentials. We first consider the case of a massless dilaton with a quadratic coupling to matter. We perform a full numerical…

Astrophysics · Physics 2009-01-14 Alain Coc , Keith A. Olive , Jean-Philippe Uzan , Elisabeth Vangioni

Some recent results on rotating self-gravitating configurations composed with Bosons and Fermions are reported. Given a star composed of both Bosons and Fermions without interaction, it is shown that it is possible to obtain stable slowly…

Astrophysics · Physics 2016-11-09 Claudio M. G. de Sousa

A large class of scalar-tensor theories of gravity exhibit a screening mechanism that dynamically suppresses fifth forces in the Solar system and local laboratory experiments. Technically, at the scalar field equation level, this usually…

General Relativity and Quantum Cosmology · Physics 2022-12-21 Hugo Lévy , Joël Bergé , Jean-Philippe Uzan

A self-consistent field method is developed, which can be used to construct models of differentially rotating stars to first post-Newtonian order. The rotation law is specified by the specific angular momentum distribution j(m), where m is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Yuk Tung Liu

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 construct boson star configurations in quantum field theory using the semiclassical gravity approximation. Restricting our attention to the static case, we show that the semiclassical Einstein-Klein-Gordon system for a {\it single real…

General Relativity and Quantum Cosmology · Physics 2023-03-08 Miguel Alcubierre , Juan Barranco , Argelia Bernal , Juan Carlos Degollado , Alberto Diez-Tejedor , Miguel Megevand , Darío Núñez , Olivier Sarbach

The formalism of geometric algebra can be described as deformed super analysis. The deformation is done with a fermionic star product, that arises from deformation quantization of pseudoclassical mechanics. If one then extends the…

Mathematical Physics · Physics 2009-11-10 Peter Henselder , Allen C. Hirshfeld , Thomas Spernat

We discuss the Damour--Esposito-Far\`ese model of gravity, which predicts the spontaneous scalarization of neutron stars in a certain range of parameter space. In the cosmological setup, the scalar field responsible for scalarization is…

General Relativity and Quantum Cosmology · Physics 2019-11-27 Timothy Anson , Eugeny Babichev , Sabir Ramazanov

This paper is devoted to study cylindrically symmetric stellar filaments in self-interacting Brans-Dicke gravity. For this purpose, we construct polytropic filamentary models through generalized Lane-Emden equation in Newtonian regime. The…

General Physics · Physics 2016-06-22 M. Sharif , Rubab Manzoor

We build analytical models of spherically symmetric stars in the brane-world, in which the external space-time contains both an ADM mass and a tidal charge. In order to determine the interior geometry, we apply the principle of minimal…

General Relativity and Quantum Cosmology · Physics 2013-03-26 Roberto Casadio , Jorge Ovalle

The general solution of Einstein's gravity equation in $D$ dimensions for an anisotropic and spherically symmetric matter distribution is calculated in a bulk with position dependent cosmological constant. Results for $n$ concentric…

General Relativity and Quantum Cosmology · Physics 2013-03-01 I. C. Jardim , R. R. Landim , G. Alencar , R. N. Costa Filho

We present a derivation of the basic equations and boundary conditions for relativistic static spherically symmetric stars (SSSS) in the model of minimal dilatonic gravity (MDG) which offers an alternative and simultaneous description of…

General Relativity and Quantum Cosmology · Physics 2015-07-21 Plamen P. Fiziev

Starting from Clifton's spherical static solution for f(R)-gravity we can derive axial symmetric solutions using a methods that takes the advantage of a complex coordinate transformation. The new solutions are generated by applying the…

General Relativity and Quantum Cosmology · Physics 2011-11-10 Mariafelicia De Laurentis

We study the Brans-Dicke model in the presence of an axion. The dynamical equations are solved when the fields are space independent and the metric is spatially flat. It is found that at late time the scale factor undergoes decelerated…

High Energy Physics - Theory · Physics 2009-10-30 Sudipta Mukherji
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