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We consider the Weyl-Dirac theory within the framework of the weak field approximation and show that the resulting gravitational potential differs from that of Newtonian by a repulsive correction term increasing with distance. The scale of…

General Relativity and Quantum Cosmology · Physics 2010-11-19 S. Mirabotalebi , S. Jalalzadeh , S. Movahed , H. R. Sepangi

In this paper we apply the symmetry principle in order to search for an alternative unified explanation of several cosmological puzzles such as the present stage of accelerated expansion of the Universe and the Hubble tension issue, among…

General Relativity and Quantum Cosmology · Physics 2023-01-13 Israel Quiros

A possibility of journeys through antigravity has recently been proposed, with the suggestion that Weyl-invariant extension of scalars coupled to Einstein gravity allows for an unambiguous classical evolution through cosmological…

High Energy Physics - Theory · Physics 2015-06-17 John Joseph M. Carrasco , Wissam Chemissany , Renata Kallosh

In two-dimensional dilaton gravity theories, there may exist a global Weyl invariance which makes black hole spurious. If the global invariance and the local Weyl invariance of the matter coupling are intact at the quantum level, there is…

High Energy Physics - Theory · Physics 2015-06-26 Takanori Fujiwara , Yuji Igarashi , Jisuke Kubo

We derive a Weyl invariant equation for Gravity by gauging the global Weyl invariance of vacuum Einstein equations. The equation is linear in the curvature and a natural generalization of Einstein equations to Weyl geometry. The system has…

General Relativity and Quantum Cosmology · Physics 2024-12-03 Máximo Bañados

The higher dimensional Weyl curvature induces on the brane a new source of gravity. This Weyl fluid of geometrical origin (reducing in the spherically symmetric, static configuration to a dark radiation and dark pressure) modifies…

General Relativity and Quantum Cosmology · Physics 2015-06-05 K. C. Wong , T. Harko , K. S. Cheng , L. Á. Gergely

The postulate of universal Weyl conformal symmetry for all elementary physical fields introduces nonclassical gravitational effects in both conformal gravitation(CG) and the conformal Higgs model (CHM). The resulting theory is found to…

General Relativity and Quantum Cosmology · Physics 2023-12-27 R. K. Nesbet

Galaxy rotation curves determined observationally out to a radius well beyond the galaxy cores can provide a critical test of modified gravity models without dark matter. The predicted rotational velocity curve obtained from…

Astrophysics of Galaxies · Physics 2015-03-05 J. W. Moffat , V. T. Toth

Light deflection offers an unbiased test of Weyl's gravity since no assumption on the conformal factor needs to be made. In this second paper of our series ``Light deflection in Weyl gravity'', we analyze the constraints imposed by light…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Pireaux

A Weyl invariant extension of Einstein gravity is studied. It simply consists in the group averaging of Einstein's action under Weyl transformations. Contradicting cherished beliefs, a conformal anomaly is found in the trace of the…

High Energy Physics - Theory · Physics 2013-11-14 Enrique Alvarez , Mario Herrero-Valea

A classical nonlocal generalization of Einstein's theory of gravitation has recently been developed via the introduction of a scalar causal "constitutive" kernel that must ultimately be determined from observational data. It turns out that…

Astrophysics of Galaxies · Physics 2014-05-14 S. Rahvar , B. Mashhoon

In a previous paper we presented a typical set of galactic rotation curves associated with the linear gravitational potential of the conformal invariant fourth order theory of gravity which has recently been advanced by Mannheim and Kazanas…

Astrophysics · Physics 2009-09-25 PHILIP D. MANNHEIM

We discuss the cosmological evolution of the Weyl conformal geometry and its associated Weyl quadratic gravity. The Einstein gravity (with a positive cosmological constant) is recovered in the spontaneously broken phase of Weyl gravity;…

General Relativity and Quantum Cosmology · Physics 2022-06-24 D. M. Ghilencea , T. Harko

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

Within vacuum Weyl gravity, we obtain a solution by which, using different choices of the conformal factor, we derive metrics describing (i)~a bounce of the universe; (ii)~toroidal and spherical wormholes; and (iii)~a change in metric…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Vladimir Dzhunushaliev , Vladimir Folomeev

A model for the dark halos of galaxy clusters, based on the Weyl geometric scalar tensor theory of gravity (WST) with a MOND-like approximation, is proposed. It is uniquely determined by the baryonic mass distribution of hot gas and stars.…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-28 Erhard Scholz

In this paper we give an extensive description of Weyl quadratic gravity as the gauge theory of the Weyl group. The previously discovered (vectorial) torsion/non-metricity equivalence is shown to be built-in as it corresponds to a…

High Energy Physics - Theory · Physics 2025-02-25 Cezar Condeescu , Andrei Micu

Higher order curvature gravity has recently received a lot of attention due to the fact that it gives rise to cosmological models which seem capable of solving dark energy and quintessence issues without using "ad hoc" scalar fields. In…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Capozziello , V. F. Cardone , S. Carloni , A. Troisi

Motivated by an axiomatic approach to characterize space-time it is investigated a reformulation of Einstein's gravity where the pseudo-riemannian geometry is substituted by a Weyl one. It is presented the main properties of the Weyl…

General Relativity and Quantum Cosmology · Physics 2011-12-19 F. P. Poulis , J. M. Salim

Considering the GAIA data for {$\approx 10^6$} stars around the {barycenter,} we estimate the fractal dimension for different regions in the Milky Way. Then we use those fractal dimensions to calculate the gravitational potential…

Astrophysics of Galaxies · Physics 2020-08-04 T Canavesi