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Recently, there has been an interest in inflation and modified gravity with a Weyl term added to the general-relativistic action (N. Derulle, M. Sasaki, Y. Sendouda and A. Youssef, JCAP, 3, 040 (2011)). In this paper we study empirical…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-13 Wei-Tou Ni

Theory of light absorption and circular photocurrent in Weyl semimetals is developed for arbitrary large light intensities with account for both elastic and inelastic relaxation processes of Weyl fermions. The direct optical transition rate…

Mesoscale and Nanoscale Physics · Physics 2019-10-21 N. V. Leppenen , E. L. Ivchenko , L. E. Golub

While the deflection of light is achromatic in General Relativity, it is not always so in several new-physics models (e.g. certain quantum-gravity and string-inspired models, models with nonminimal photon-gravity coupling or with massive…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-31 P. Egorov , M. Guzinin , H. Hakopyan , S. Troitsky

We present a novel test of general relativity (GR): measuring the geometric component of the time delay due to gravitational lensing. GR predicts that photons and gravitational waves follow the same geodesic paths and thus experience the…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-19 David Rubin , Istvan Szapudi , Benjamin J. Shappee , Gagandeep S. Anand

Geodesics are studied in one of the Weyl metrics, referred to as the M--Q solution. First, arguments are provided, supporting our belief that this space--time is the more suitable (among the known solutions of the Weyl family) for…

General Relativity and Quantum Cosmology · Physics 2009-11-10 L. Herrera

This paper presents three aspects by which the Weyl geometric generalization of Riemannian geometry, and of Einstein gravity, sheds light on actual questions of physics and its philosophical reflection. After introducing the theory's…

General Relativity and Quantum Cosmology · Physics 2015-07-28 Erhard Scholz

We consider cosmological implications of the Weyl geometric gravity theory. The basic action of the model is obtained from the simplest conformally invariant gravitational action, constructed, in Weyl geometry, from the square of the Weyl…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Tiberiu Harko , Shahab Shahidi

Recent experiments on ultra slow light in strongly dispersive media by several research groups reporting slowing down of the optical pulses down to speeds of a few metres per second encourage us to examine the intriguing possibility of…

Optics · Physics 2007-12-27 N. Kumar

Eventual flattening of velocity dispersion profiles of some galactic globular clusters in the Milky Way cannot be explained in the framework of Newtonian gravity and hence in general theory of relativity in the weak field limit, without…

General Relativity and Quantum Cosmology · Physics 2019-07-31 Tousif Islam

We study the Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology in the Weyl-transverse (WTDiff) gravity in a general space-time dimension. The WTDiff gravity is invariant under both the local Weyl (conformal) transformation and the volume…

General Relativity and Quantum Cosmology · Physics 2016-12-14 Ichiro Oda

We construct a Weyl transverse diffeomorphism invariant theory of symmetric teleparallel gravity by employing the Weyl compensator formalism. The low-energy dynamics has a single spin two gravition without a scalar degree of freedom. By…

General Relativity and Quantum Cosmology · Physics 2022-07-06 Yu Nakayama

Understanding the deflection of light by a massive deflector, as well as the associated gravitational lens phenomena, require the use of the theory of General Relativity. I consider here a classical approach, based on Newton's equation of…

Physics Education · Physics 2008-03-05 T. Garel

We consider the geodesic deviation equation, describing the relative accelerations of nearby particles, and the Raychaudhuri equation, giving the evolution of the kinematical quantities associated with deformations (expansion, shear and…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Jin-Zhao Yang , Shahab Shahidi , Tiberiu Harko , Shi-Dong Liang

We review recent developments in physical implications of Weyl conformal geometry. The associated Weyl quadratic gravity action is a gauge theory of the Weyl group of dilatations and Poincar\'e symmetry. Weyl conformal geometry is defined…

High Energy Physics - Theory · Physics 2025-06-05 D. M. Ghilencea

We study strong gravitational lensing in a static, spherically symmetric, naked singularity spacetime, without a photon sphere. The nature of the singularity is found to be lightlike. We discuss the characteristic lensing features of this…

General Relativity and Quantum Cosmology · Physics 2020-09-25 Suvankar Paul

We discuss the concepts of Weyl and Riemann frames in the context of metric theories of gravity and state the fact that they are completely equivalent as far as geodesic motion is concerned. We apply this result to conformally flat…

General Relativity and Quantum Cosmology · Physics 2015-05-27 C. Romero , J. B. Fonseca-Neto , M. L. Pucheu

In this paper we obtain the linear Weyl gravity in de Sitter background. Its linear form in five-dimensional ambient space notation has also been obtained. From the group theoretical point of view, we show that this conformal invariant…

General Relativity and Quantum Cosmology · Physics 2010-12-23 M. V. Takook , M. R. Tanhayi

A crucial property of Weyl gravity is its conformal invariance. It is shown how this gauge symmetry is exactly reflected by the two constraints in the Hamiltonian framework. Since the spatial 3-metric is one of the configuration variables,…

General Relativity and Quantum Cosmology · Physics 2018-09-26 Qian Chen , Yongge Ma

In this paper, we investigate the cosmological implications and constraints of Weyl-type $f(Q, T)$ gravity. This theory introduces a coupling between the non-metricity $Q$ and the trace $T$ of the energy-momentum tensor, using the…

General Relativity and Quantum Cosmology · Physics 2024-03-27 Alnadhief H. A. Alfedeel , M. Koussour , N. Myrzakulov

In this work, we theoretically investigate the deflection of light for strong- and weak-field regimes in the background of an electrically charged BH described in Kalb-Ramond gravity, which introduces the Lorentz symmetry violation…

General Relativity and Quantum Cosmology · Physics 2026-02-27 C. F. S. Pereira , Marcos V. de S. Silva , A. R. Soares , A. A. Araújo Filho , R. L. L. Vitória , H. Belich