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A modified Newton's gravity is obtained as the weak field approximation of the Einstein's equation in Finsler space. It is found that a specified Finsler structure makes the modified Newton's gravity equivalent to the modified Newtonian…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Zhe Chang , Xin Li

A nonlocal form of the effective gravitational action could cure the unboundedness of euclidean gravity with Einstein action. On sub-horizon length scales the modified gravitational field equations seem compatible with all present tests of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 C. Wetterich

We resurrect Eddington's proposal for the gravitational action in the presence of a cosmological constant and extend it to include matter fields. We show that the Newton-Poisson equation is modified in the presence of sources and that…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-04 Maximo Banados , Pedro G. Ferreira

We study modifications of general relativity, GR, with nonlinear dispersion relations which can be geometrized on tangent Lorentz bundles. Such modified gravity theories, MGTs, can be modeled by gravitational Lagrange density functionals…

General Physics · Physics 2017-06-13 Panayiotis Stavrinos , Olivia Vacaru , Sergiu I. Vacaru

We present a theory of modified gravity, inspired by the gauge theories, where the commutator algebra of covariant derivative gives us an added term with respect to the General Relativity, which represents the interaction of gravity with a…

General Relativity and Quantum Cosmology · Physics 2012-01-05 M. Hamani Daouda , Manuel E. Rodrigues , M. J. S. Houndjo

We develop the complete composite theory of gravity, in which the gauge vector fields of the Yang-Mills theory with Lorentz symmetry group are expressed in terms of the tetrad variables obtained from the decomposition of a metric. A key…

General Relativity and Quantum Cosmology · Physics 2021-10-07 Hans Christian Öttinger

A recent paper studies a modification of Einstein-aether theory in which the aether vector is restricted, at the level of the action, to be the gradient of a scalar. In this comment we note that this scalar version of Einstein-aether theory…

General Relativity and Quantum Cosmology · Physics 2014-06-13 Ted Jacobson , Antony J. Speranza

Classically, unimodular gravity is known to be equivalent to General Relativity (GR), except for the fact that the effective cosmological constant $\Lambda$ has the status of an integration constant. Here, we explore various formulations of…

High Energy Physics - Theory · Physics 2014-11-18 Bartomeu Fiol , Jaume Garriga

Implementing Poincar\'e's `geometric conventionalism' a scalar Lorentz-covariant gravity model is obtained based on gravitationally modified Lorentz transformations (or GMLT). The modification essentially consists of an appropriate…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Jan Broekaert

The field equations in modified gravity theories possess an important decoupling property with respect to certain classes of nonholonomic frames. This allows us to construct generic off--diagonal solutions depending on all spacetime…

General Relativity and Quantum Cosmology · Physics 2015-02-23 Sergiu I. Vacaru

We consider the possibility of generalizing the Newtonian law of gravity and the transition to a general relativistic model for weak fields with the inclusion of a repulsive term identified as a cosmological constant. The analysis includes…

General Relativity and Quantum Cosmology · Physics 2020-12-10 N. N. Fimin , V. M. Chechetkin

Recently proposed quantization in field theory based on an analogue of Hamiltonian formulation which treats space and time on equal footing (the so-called De Donder-Weyl theory) is applied to General Relativity in metric variables. We…

General Relativity and Quantum Cosmology · Physics 2007-05-23 I. V. Kanatchikov

We investigate Einstein theories of gravity, coupled to a scalar field \vphi and point-like matter, which are characterized by a scalar field-dependent matter coupling function e^{H(\vphi)}. We show that under mild constraints on the form…

General Relativity and Quantum Cosmology · Physics 2014-11-18 M. Cadoni , M. Casula

We present a resum\'e on the modified theory of gravity, called pseudo-complex General Relativity (pc-GR). It is the second in a series of papers, where the first one (Boller et al. 2019, referred to as paper I) discussed the observational…

Astrophysics of Galaxies · Physics 2019-04-10 P. O. Hess , Th. Boller , A. Mueller , H. Stoecker

The Einstein-Aether theory provides a simple, dynamical mechanism for breaking Lorentz invariance. It does so within a generally covariant context and may emerge from quantum effects in more fundamental theories. The theory leads to a…

General Relativity and Quantum Cosmology · Physics 2009-01-22 J. A. Zuntz , P. G. Ferreira , T. G. Zlosnik

It has been recently shown that there is a particular combination of conformal invariants in six dimensions which accepts a generic Einstein space as a solution. The Lagrangian of this Conformal Gravity theory -- originally found by Lu,…

High Energy Physics - Theory · Physics 2021-08-04 Giorgos Anastasiou , Ignacio J. Araya , Cristobal Corral , Rodrigo Olea

This note includes results of a study of stationary spherically symmetric ``dark holes'', objects merging central black holes and peripheral scalar graviton dark haloes arising in the framework of the modified gravity -- the quartet-metric,…

General Relativity and Quantum Cosmology · Physics 2025-07-15 Yu. F. Pirogov , O. V. Zenin

We derive the equations of motion that arise from the one-loop effective action for the geometry of 3+1 dimensional quantum branes in the IKKT matrix model. These equations are cast into the form of generalized Einstein equations, with…

High Energy Physics - Theory · Physics 2023-12-06 Kaushlendra Kumar , Harold C. Steinacker

A toy model of Einstein gravity with a Gauss-Bonnet classically "entropic" term mimicking a quantum correction is considered. The static black hole solution due to Tomozawa is found and generalized with the inclusion of non trivial horizon…

General Relativity and Quantum Cosmology · Physics 2013-10-15 Guido Cognola , Ratbay Myrzakulov , Lorenzo Sebastiani , Sergio Zerbini

We give a pedagogical account of noncommutative gauge and gravity theories, where the exterior product between forms is deformed into a $\star$-product via an abelian twist (e.g. the Groenewold-Moyal twist). The Seiberg-Witten map between…

High Energy Physics - Theory · Physics 2023-06-21 Paolo Aschieri , Leonardo Castellani