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Related papers: Exact String-Like Solutions in Conformal Gravity

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The field equations of a special class of teleparallel theory of gravitation and electromagnetic fields have been applied to tetrad space having cylindrical symmetry with four unknown functions of radial coordinate $r$ and azimuth angle…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Gamal G. L. Nashed

The cosmological constant problem and the compatibility of gravity with quantum mechanics are the two most pressing problems in all of gravitational theory. While string theory nicely addresses the latter, it has so far failed to provide…

High Energy Physics - Theory · Physics 2007-07-17 Philip D. Mannheim

We derive, in 2+1 dimensions, classical solutions for metric and motion of two or more spinning particles, in the conformal Coulomb gauge introduced previously. The solutions are exact in the $N$-body static case, and are perturbative in…

High Energy Physics - Theory · Physics 2009-10-30 M. Ciafaloni , P. Valtancoli

We present a scale-invariant theory, conformal gravity, which closely resembles the geometrodynamical formulation of general relativity (GR). While previous attempts to create scale-invariant theories of gravity have been based on Weyl's…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Edward Anderson , Julian Barbour , Brendan Foster , Niall O'Murchadha

We present an exact solution to the equations of massive gravity that displays cosmological constant-like behavior for any spherically symmetric distribution of matter, including arbitrary time dependence. On this solution, the new degrees…

High Energy Physics - Theory · Physics 2012-11-22 Pierre Gratia , Wayne Hu , Mark Wyman

We reconsider the cosmic string perturbative solution to the classical fourth-order gravity field equations, obtained in Ref.\cite{CLA94}, and we obtain that static, cylindricaly symmetric gauge cosmic strings, with constant energy density,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Manuela Campanelli

We review some results concerning the properties of static, spherically symmetric solutions of multidimensional theories of gravity: various scalar-tensor theories and a generalized string-motivated model with multiple scalar fields and…

General Relativity and Quantum Cosmology · Physics 2015-06-25 K. A. Bronnikov , V. N. Melnikov

A nonstationary spherically symmetric problem for conformal geometrodynamics equations is considered and general exact solutions in quadratures are obtained. Involvement of Weyl degrees of freedom allows us to consider the problem with…

General Relativity and Quantum Cosmology · Physics 2007-11-13 Mikhail V. Gorbatenko

We analyse the vacuum static spherically symmetric space-time for a specific class of non-conservative theories of gravity based on the Rastall's theory. We obtain a new vacuum solution which has the same structure as the Schwarzschild-de…

General Relativity and Quantum Cosmology · Physics 2016-06-15 A. M. Oliveira , H. E. S. Velten , J. C. Fabris

Solutions to the field equations of the Nonsymmetric Gravitational Theory with $g_[i0] = 0$ are obtained for the homogeneous, plane-symmetric, time-dependent case, both in vacuum and in the presence of a perfect fluid. Cosmological…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Pierre Savaria

Via a straightforward integration of the Einstein equations with cosmological constant, all static circularly symmetric perfect fluid 2+1 solutions are derived. The structural functions of the metric depend on the energy density, which…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Alberto A. Garcia , Cuauhtemoc Campuzano

Gravitation is described in the context of a dilatonic theory that is conformally related to general relativity. All dimensionless ratios of fundamental dimensional quantities, e.g. particle masses and the Planck mass, as well as the…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-21 Meir Shimon

In this paper we calculate the kinematical quantities of the Raychaudhuri equations, to characterize a congruence of time-like integral curves, according to the vacuum radial solution of Weyl theory of gravity. Also the corresponding flows…

General Physics · Physics 2019-05-09 Mohsen Fathi

We analyze an alternative theory of gravity characterized by metrics that are tensor density of rank(0,2)and weight-1/2.The metric compatibility condition is supposed to hold. The simplest expression for the action of gravitational field is…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Amir H. Abbassi , Amir M. Abbassi

In this paper we study regular cosmic string solutions of the non-Abelian Higgs model coupled with the Einstein gravity. In order to do that, we constructed a set of coupled differential ordinary equation. Because there is no closed…

High Energy Physics - Theory · Physics 2015-07-08 Antônio de Pádua Santos , Eugênio R. Bezerra de Mello

We consider some aspects of conformal symmetry in a metric-scalar-torsion system. It is shown that, for some special choice of the action, torsion acts as a compensating field and the full theory is conformally equivalent to General…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. A. Helayel-Neto , A. Penna-Firme , I. L. Shapiro

In this paper we consider an axial torsion to build metric-compatible connections in conformal gravity, with gauge potentials; the geometric background is filled with Dirac spinors: scalar fields with suitable potentials are added…

General Relativity and Quantum Cosmology · Physics 2014-03-12 Luca Fabbri

In this work we find analytical solutions to the null geodesics around a black hole in the conformal Weyl gravity. Exact expressions for the horizons are found, and they depend on the cosmological constant and the coupling constants of the…

General Relativity and Quantum Cosmology · Physics 2013-06-26 J. R. Villanueva , Marco Olivares

We study the static black hole solutions of generalized two-dimensional dilaton-gravity theories generated by pointlike mass sources, in the hypothesis that the matter is conformally coupled. We also discuss the motion of test particles.…

General Relativity and Quantum Cosmology · Physics 2009-11-10 M. Melis , S. Mignemi

We studied spherically symmetric solutions in scalar-torsion gravity theories in which a scalar field is coupled to torsion with a derivative coupling. We obtained the general field equations from which we extracted a decoupled master…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Georgios Kofinas , Eleftherios Papantonopoulos , Emmanuel N. Saridakis