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We provide a gauge-invariant theory of gravitation in the context of Weyl Integrable Space-Times. After making a brief review of the theory's postulates, we carefully define the observers' proper-time and point out its relation with…

General Relativity and Quantum Cosmology · Physics 2014-10-31 F. P. Poulis , J. M. Salim

We present a parametric study of the spacetime structures obtainable in Weyl conformal gravity's dyonic Reissner-Nordstr\"{o}m solution. We derive expressions for photon sphere radii and horizons for this metric in terms of the conformal…

General Relativity and Quantum Cosmology · Physics 2026-02-05 Reinosuke Kusano , Miguel Yulo Asuncion , Keith Horne

We consider a mimetic type extension of the Weyl geometric gravity theory, by assuming that the metric of the space-time manifold can be parameterized in terms of a scalar field, called the mimetic field. The action of the model is obtained…

General Relativity and Quantum Cosmology · Physics 2025-03-19 Daria-Ioana Visa , Tiberiu Harko , Shahab Shahidi

We extend the f(R) gravity action by including a generic dependence upon the Weyl tensor, and further generalize it to supergravity by using the super-curvature (R) and super-Weyl (W) chiral superfields in N=1 chiral curved superspace. We…

High Energy Physics - Theory · Physics 2013-07-24 Sergei V. Ketov , Takahiro Terada

We study the Hamiltonian structure of unimodular-like theories, where the cosmological constant (or other supposed constants of nature) are demoted from fixed parameters to classical constants of motion. No new local degrees of freedom are…

High Energy Physics - Theory · Physics 2024-04-30 Raymond Isichei , João Magueijo

The on shell equivalence of first order and second order formalisms for the Einstein-Hilbert action does not hold for those actions quadratic in curvature. It would seem that by considering the connection and the metric as independent…

High Energy Physics - Theory · Physics 2017-02-15 Enrique Alvarez , Sergio Gonzalez-Martin

The four-dimensional gauge group of general relativity corresponds to arbitrary coordinate transformations on a four-manifold. Theories of gravity with a dynamical structure remarkably like Einstein's theory can be obtained on the basis of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Julian Barbour , Niall O Murchadha

We study various classical aspects of the Weyl transverse (WTDiff) gravity in a general space-time dimension. First of all, we clarify a classical equivalence among three kinds of gravitational theories, those are, the conformally-invariant…

High Energy Physics - Theory · Physics 2017-05-24 Ichiro Oda

Complexifying space time has many interesting applications, from the construction of higher dimensional unification, to provide a useful framework for quantum gravity and to better define some local symmetries that suffer singularities in…

General Relativity and Quantum Cosmology · Physics 2023-09-22 Eduardo Guendelman

The possibility of the extension of spatial diffeomorphisms to a larger family of symmetries in a class of classical field theories is studied. The generator of the additional local symmetry contains a quadratic kinetic term and a potential…

High Energy Physics - Theory · Physics 2015-05-18 Szilard Farkas , Emil J. Martinec

We compute the one-loop effective action in unimodular gravity, starting from two different classical formulations of the theory. We find that the effective action is the same in both cases, and agrees with the one of General Relativity.

General Relativity and Quantum Cosmology · Physics 2018-01-31 R. de Leon Ardon , N. Ohta , R. Percacci

We propose a new class of gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the spacetime manifold. For the matter we choose appropriate…

High Energy Physics - Theory · Physics 2015-07-23 Eduardo Guendelman , Emil Nissimov , Svetlana Pacheva

This thesis deals with the construction of conserved charges for asymptotically flat spacetimes at spatial infinity in four spacetime dimensions in a hopefully pedagogical way. As a first motivation of this work, it highlights the…

High Energy Physics - Theory · Physics 2011-12-20 François Dehouck

We have investigated the vacuum maximally symmetric solutions of recently proposed density-metric unimodular gravity theory,the results are widely different from inflationary senario.The exponential dependence on time in deSitter space is…

General Relativity and Quantum Cosmology · Physics 2015-05-18 Amir H. Abbassi , Amir M. Abbassi

The usual interpretation of Weyl geometry is modified in two senses. First, both the additive Weyl connection and its variation are treated as (1, 2) tensors under the action of Weyl covariant derivative. Second, a modified covariant…

General Relativity and Quantum Cosmology · Physics 2013-09-18 Fang-Fang Yuan , Yong-Chang Huang

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

Recently, a gauge theory of unified gravity [Rep. Prog. Phys. 88, 057802 (2025)] has been developed to extend the Standard Model to include gravity. Here we present unified gravity using the ordinary four-vector and tensor field notation of…

General Relativity and Quantum Cosmology · Physics 2025-08-12 Mikko Partanen , Jukka Tulkki

It is the object of the present paper to unimodularise a disformal bimetric scalar-tensor theory, thereby defining what we call bimodular gravity. We impose one unimodular constraint per metric via multipliers $\lambda_{1,2}$ and show that…

General Relativity and Quantum Cosmology · Physics 2025-11-18 James Hallam , João Magueijo

Within the context of a $5D$ space-time, we construct a unified theory of gravity and electromagnetism from which the Einstein field equations and Maxwell equations emerge, with homogenous Maxwell equations appearing naturally. We also…

General Relativity and Quantum Cosmology · Physics 2010-06-17 A. Borzou , H. R. Sepangi

It is first argued that radiation by a uniformly accelerated charge in flat space-time indicates the need for a unified geometric theory of gravity and electromagnetism. Such a theory, based on a metric-affine $U_4$ manifold, is constructed…

General Physics · Physics 2018-08-30 Partha Ghose