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Related papers: Brane-$f(R)$ gravity and dark matter

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A version of the virial theorem, which takes into account the effects of the non-compact extra-dimensions, is derived in the framework of the brane world models. In the braneworld scenario, the four dimensional effective Einstein equation…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Harko , K. S. Cheng

We generalize the virial theorem in f(R) modified gravity using the collisionless Boltzmann equation. We find supplementary geometric terms in the modified Einstein equation providing an effective contribution to the gravitational energy.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Christian G. Boehmer , Tiberiu Harko , Francisco S. N. Lobo

We use the collision-free Boltzmann equation in Palatini $f({\mathcal{R}})$ gravity to derive the virial theorem within the context of the Palatini approach. It is shown that the virial mass is proportional to certain geometrical terms…

General Relativity and Quantum Cosmology · Physics 2015-05-13 A. S. Sefiedgar , K. Atazadeh , H. R. Sepangi

We consider solutions with conformal symmetry of the static, spherically symmetric gravitational field equations in the vacuum in the brane world scenario. By assuming that the vector field generating the symmetry is non-static, the general…

General Relativity and Quantum Cosmology · Physics 2010-11-19 M. K. Mak , T. Harko

A class of exact solutions of the gravitational field equations in the vacuum on the brane are obtained by assuming the existence of a conformal Killing vector field, with non-static and non-central symmetry. In this case the general…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Harko , M. K. Mak

The behavior of the angular velocity of a test particle moving in a stable circular orbit in the vacuum on the brane is considered. In the brane world scenario, the four dimensional effective Einstein equation acquire extra terms, called…

General Relativity and Quantum Cosmology · Physics 2008-11-26 C. G. Boehmer , T. Harko

We consider a brane world scenario in which the bulk action is assumed to have the form of a generic function of the Ricci scalar $f(\mathcal{R})$ and derive the resulting Einstein field equations on the brane. In a constant curvature bulk…

General Relativity and Quantum Cosmology · Physics 2024-11-18 A. Borzou , H. R. Sepangi , S. Shahidi , R. Yousefi

A version of the virial theorem is derived in a brane-world scenario in the framework of a warped DGP model where the action on the brane is an arbitrary function of the Ricci scalar, L(R). The extra terms in the modified Einstein equations…

General Physics · Physics 2012-12-11 Malihe Heydari-Fard , Mohaddese Heydari-Fard

Bose-Einstein condensate dark matter model and Randall-Sundrum type 2 brane-world theory are tested with galactic rotation curves. Analytical expressions are derived for the rotational velocities of test particles around the galactic center…

General Relativity and Quantum Cosmology · Physics 2014-09-12 Marek Dwornik , Zoltán Keresztes , László Árpád Gergely

In the present investigation flat rotational curves of the galaxies are considered under the framework of brane-world models where the 4d effective Einstein equation has extra terms which arise from the embedding of the 3-brane in the $5d$…

Astrophysics · Physics 2008-11-07 F. Rahaman , M. Kalam , A. DeBenedictis , A. A. Usmani , Saibal Ray

We obtain the virial theorem within the context of a brane-world model without mirror symmetry or any form of junction condition. Taking a constant curvature bulk (neglecting non-local bulk effects), the local bulk effects generate a…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Malihe Heydari-Fard , Hamid R. Sepangi

In the braneworld scenario, the four dimensional effective Einstein equation has extra terms which arise from the embedding of the 3-brane in the bulk. These non-local effects, generated by the free gravitational field of the bulk, may…

Astrophysics · Physics 2016-08-30 T. Harko , K. S. Cheng

We generalize the virial theorem to the warped DGP brane world scenario and consider its implications on the virail mass. In this theory the four dimensional scalar curvature term is included in the bulk action and the resulting four…

General Physics · Physics 2015-06-12 Malihe Heydari-Fard , Mohaddese Heydari-Fard

The simplest gauge gravitation theory in Riemann-Cartan space-time leading to the solution of the problem of cosmological singularity and dark energy problem is investigated with purpose to solve the dark matter problem. It is shown that…

General Relativity and Quantum Cosmology · Physics 2017-05-09 A. V. Minkevich

It is shown that Einstein's equations on the brane can be received from the multi-dimensional vector field equations in pseudo-Euclidean space. The idea is based on the observation that the brane geometry can be equivalently described by…

High Energy Physics - Theory · Physics 2011-07-19 Merab Gogberashvili

The $f(R)$ gravity models formulated in Einstein conformal frame are equivalent to Einstein gravity together with a minimally coupled scalar field. The scalar field couples with the matter sector and the coupling term is given by the…

General Relativity and Quantum Cosmology · Physics 2012-07-24 Yousef Bisabr

We consider the possibility that the Eddington-Born-Infeld (EBI) modified gravity provides an alternative explanation for the mass discrepancy in clusters of galaxies. For this purpose we derive the modified Einstein field equations,…

General Relativity and Quantum Cosmology · Physics 2015-12-07 Noelia S. Santos , Janilo Santos

In the braneworld scenario the four dimensional effective Einstein equation has extra source terms, which arise from the embedding of the 3-brane in the bulk. These non-local effects, generated by the free gravitational field of the bulk,…

General Relativity and Quantum Cosmology · Physics 2011-10-14 L. Á. Gergely , T. Harko , M. Dwornik , G. Kupi , Z. Keresztes

f(R)-gravity with geometric torsion (not related to any spin fluid) is considered in a cosmological context. We derive the field equations in vacuum and in presence of perfect-fluid matter and discuss the related cosmological models.…

General Relativity and Quantum Cosmology · Physics 2009-01-21 S. Capozziello , R. Cianci , C. Stornaiolo , S. Vignolo

Two problems related to dark matter is considered in the context of a brane world model in which the confinement of gauge fields on the brane is achieved by invoking a confining potential. First, we show that the virial mass discrepancy can…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Shahab Shahidi , Hamid Reza Sepangi
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