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Related papers: Congruence Kinematics in Conformal Gravity

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We apply singularity analysis to investigate the integrability properties of the gravitational field equations in Weyl Integrable Spacetime for a spatially flat Friedmann--Lema\^itre--Robertson--Walker background spacetime induced with an…

General Relativity and Quantum Cosmology · Physics 2022-06-28 Andronikos Paliathanasis

We consider the motion of test particles and light rays in a static cylindrically symmetric conformal spacetime given by Said et al [1]. We derive the equations of motion and present their analytical solutions in terms of the Weierstrass…

General Relativity and Quantum Cosmology · Physics 2016-08-16 Bahareh Hoseini , Reza Saffari , Saheb Soroushfar , Jutta Kunz , Saskia Grunau

The conformal gravity fit to observed galactic rotation curves requires {\gamma}>0. On the other hand, conventional method for light deflection by galaxies gives a negative contribution to Schwarzschild value for {\gamma}>0, which is…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Carlo Cattani , Massimo Scalia , Ettore Laserra , Ivana Bochicchio , Kamal K. Nandi

An important task faced by all approaches of quantum gravity is to incorporate superpositions and quantify quantum uncertainties of spacetime causal relations. We address this task in 2D. By identifying a global $Z_2$ symmetry of 1+1D…

General Relativity and Quantum Cosmology · Physics 2022-03-03 Ding Jia

We show quantitatively that an exact solution of Einstein's conformal gravity can explain very well the galactic rotation curves for a sample of 104 galaxies without need for dark matter or other exotic modification of gravity. The metric…

General Relativity and Quantum Cosmology · Physics 2019-06-13 Qiang Li , Leonardo Modesto

We study Weyl symmetry (local conformal symmetry) in unimodular gravity. It is shown that the Noether currents for both Weyl symmetry and global scale symmetry, identically vanish as in the conformally invariant scalar-tensor gravity. We…

General Relativity and Quantum Cosmology · Physics 2016-08-24 Ichiro Oda

A conformal gauge theory is used to describe and unify myriad electromechanical and magnetomechanical coupling effects observed in solid continua. Using a space-time pseudo-Riemannian metric in a finite-deformation setup and exploiting the…

Classical Physics · Physics 2023-07-19 Pranesh Roy , Sanjeev Kumar , Debasish Roy

We present a detailed investigation of the properties of the galactic rotation curves in the Weyl geometric gravity model, in which the gravitational action is constructed from the square of the Weyl curvature scalar, and of the strength of…

General Relativity and Quantum Cosmology · Physics 2023-11-29 Maria Crăciun , Tiberiu Harko

A solution to the equivalence problem in three-dimensional gravity is given and a practically useful method to obtain a coordinate invariant description of local geometry is presented. The method is a nontrivial adaptation of Karlhede…

General Relativity and Quantum Cosmology · Physics 2011-03-28 F. C. Sousa , J. B. Fonseca , C. Romero

The stationary cosmological model without closed timelike curves of G\"odel type is obtained for the ideal dust matter source within the framework of the teleparallel gravity. For a specific choice of the teleparallel gravity parameters,…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Yu. N. Obukhov , T. Vargas

We investigate (2+1)-dimensional gravity in a Weyl integrable spacetime (WIST). We show that, unlike general relativity, this scalar-tensor theory has a Newtonian limit for any dimension and that in three dimensions the congruence of world…

General Relativity and Quantum Cosmology · Physics 2015-10-21 J. E. Madriz Aguilar , C. Romero , J. B. Fonseca-Neto , T. S. Almeida , J. B. Formiga

We suggest to consider conformal factor dynamics as applying to composite boundstates, in frames of the $1/N$ expansion. In this way, a new model of effective theory for quantum gravity is obtained. The renormalization group (RG) analysis…

High Energy Physics - Theory · Physics 2009-09-17 E. Elizalde , S. D. Odintsov

The Unification of Conformal and Fuzzy gravities with Internal Interactions is based on the following two facts. The first is that the tangent group of a curved manifold and the manifold itself do not necessarily have the same dimensions.…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Gregory Patellis , Danai Roumelioti , Stelios Stefas , George Zoupanos

It has been known that the propagation of sound in fluids can be used to model acoustic spacetimes. These acoustic spacetimes offer analogue models for gravity. We use the Raychaudhuri equation to study the propagation of sound in these…

General Relativity and Quantum Cosmology · Physics 2023-08-23 Akshat Pandey

We derive the chiral kinetic theory under the presence of a gravitational Riemann curvature. It is well-known that in the chiral kinetic theory there inevitably appears a redundant ambiguous vector corresponding to the choice of the Lorentz…

High Energy Physics - Theory · Physics 2021-05-06 Tomoya Hayata , Yoshimasa Hidaka , Kazuya Mameda

We consider the recently introduced mimetic gravity, which is a Weyl-symmetric extension of the General Relativity and which can play a role of an imperfect fluid-like Dark Matter with a small sound speed. In this paper we discuss in…

General Relativity and Quantum Cosmology · Physics 2015-12-31 Katrin Hammer , Alexander Vikman

A major unsolved problem in theoretical physics is to reconcile the classical theory of general relativity with quantum mechanics. These lectures will deal with an attempt to describe quantum gravity as a path integral over geometries known…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Jan Ambjorn , Jerzy Jurkiewicz , Renate Loll

It is shown that the timelike, spacelike and null versions of the Ehlers identity, as well as ensuing Raychaudhuri equations, might be all derived within a single geometrical approach based on the definition of the Riemann curvature tensor…

General Relativity and Quantum Cosmology · Physics 2017-10-31 Eduard G. Mychelkin , Maxim A. Makukov

We discuss the relational strategy to solve the problem of time in quantum gravity and different ways in which it could be implemented, pointing out in particular the fundamentally new dimension that the problem takes in a quantum gravity…

General Relativity and Quantum Cosmology · Physics 2021-09-23 Luca Marchetti , Daniele Oriti

The space-time curvature carried by electromagnetic fields is discovered and a new unification of geometry and electromagnetism is found. Curvature is invariant under charge reversal symmetry. Electromagnetic field equations are examined…

General Relativity and Quantum Cosmology · Physics 2007-05-23 R. W. M. Woodside
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