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It is shown that Einstein gravity tends to modify the electric and magnetic fields appreciably at distances of the order of the Compton wavelength. At that distance the gravitational field becomes spin dominated rather than mass dominated.…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Kjell Rosquist

Einstein-Cartan theory is formulated in (1+2)-dimensions using the algebra of exterior differential forms. A Dirac spinor is coupled to gravity and the field equations are obtained by a variational principle. The space-time torsion is found…

General Relativity and Quantum Cosmology · Physics 2010-02-05 T. Dereli , N. Ozdemir , O. Sert

Einstein's theory of general relativity, which contains a universal value of the Planck mass, has been so far successfully invoked to explain gravitational dynamics from sub-millimeter scales to the scale of the cosmological horizon.…

Astrophysics · Physics 2009-11-13 Georg Robbers , Niayesh Afshordi , Michael Doran

Within the context of the usual semi classical investigation of Planck scale Schwarzchild Black Holes, as in Quantum Gravity, and later attempts at a full Quantum Mechanical description in terms of a Kerr-Newman metric including the…

Quantum Physics · Physics 2007-05-23 B. G. Sidharth

We present a simple gedanken experiment in which a compact object traverses a spacetime with three macroscopic spatial dimensions and $n$ compact dimensions. The compactification radius is allowed to vary, as a function of the object's…

General Relativity and Quantum Cosmology · Physics 2023-05-08 Matthew J. Lake , Shi-Dong Liang , Anucha Watcharapasorn

We propose a new formulation for 3+1 numerical relativity, based on a constrained scheme and a generalization of Dirac gauge to spherical coordinates. This is made possible thanks to the introduction of a flat 3-metric on the spatial…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. Bonazzola , E. Gourgoulhon , P. Grandclement , J. Novak

The scale invariance of the source-free Einstein field equations suggests that one might be able to model hadrons as "strong gravity" black holes, if one uses an appropriate rescaling of units or a revised gravitational coupling factor. The…

Astrophysics · Physics 2010-04-29 R. L. Oldershaw

The results of a study of Dirac's Hamiltonian for a point electron in the zero-gravity Kerr--Newman spacetime are reported; here, "zero-gravity" means G to 0, where G is Newton's constant of universal gravitation, and the limit is effected…

Mathematical Physics · Physics 2015-05-22 Michael K. -H. Kiessling , A. Shadi Tahvildar-Zadeh

An original way of presentation of the Schwarzschild black hole in the form of a point-like mass with making the use of the Dirac $\delta$-function, including a description of a continuous collapse to such a point mass, is given. A…

General Relativity and Quantum Cosmology · Physics 2017-12-29 A. N. Petrov

We study a class of Hamiltonian deformations of the massless Einstein-Klein-Gordon system in spherical symmetry for which the Dirac constraint algebra closes. The system may be regarded as providing effective equations for quantum…

General Relativity and Quantum Cosmology · Physics 2012-04-24 Andreas Kreienbuehl , Viqar Husain , Sanjeev S. Seahra

We study a complex Dirac field in the chiral representation minimally coupled to gravity in 3+1 dimensions in the context of Einstein-Cartan theory. Generically the matter content gravitates in two different ways: On the one hand, the…

General Relativity and Quantum Cosmology · Physics 2015-03-12 Adolfo Toloza

We apply in a simple model derived from quadratic $\mathcal{R}^2$ gravity the technique of Dyson-Schwinger equations to solve for its corresponding quantum theory. Particularly, we solve the classical equations of motion to get a solution…

High Energy Physics - Theory · Physics 2025-12-29 Sayantan Choudhury , Marco Frasca , Anish Ghoshal

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

Traditional derivations of the Planck mass ignore the role of charge and spin in general relativity. From the Kerr-Newman null surface and horizon radii, quantized charge and spin dependence are introduced in an extended Planck scale of…

High Energy Physics - Theory · Physics 2009-11-10 F. I. Cooperstock , V. Faraoni

As the only gravity theory with quadratic curvature terms and second-order field equations, Einstein-dilaton-Gauss-Bonnet gravity is a natural testbed to probe the high-curvature regime beyond General Relativity in a fully nonperturbative…

General Relativity and Quantum Cosmology · Physics 2023-03-15 Fabrizio Corelli , Marina De Amicis , Taishi Ikeda , Paolo Pani

We consider a spatially homogeneous and isotropic cosmological model where Dirac spinors are coupled to classical gravity. For the Dirac spinors we choose a Hartree-Fock ansatz where all one-particle wave functions are coherent and have the…

Mathematical Physics · Physics 2014-04-23 Felix Finster , Christian Hainzl

Einstein gravity minimally coupled to a scalar field with a two-parameter Higgs-like self-interaction in three spacetime dimensions is recast in terms of a Chern-Simons form for the algebra $g^{+}\oplus g^{-}$ where, depending on the sign…

High Energy Physics - Theory · Physics 2023-02-22 Marcela Cárdenas , Oscar Fuentealba , Cristián Martínez , Ricardo Troncoso

With the simplest proof ever, we justify the significance of quantum-gravity in non-relativistic quantum mechanics together with the related theories and experiments. Since the de Broglie wave length is inverse proportional to the mass, it…

Quantum Physics · Physics 2020-01-08 Lajos Diósi

The coupling between spin and torsion in the Einstein-Cartan-Sciama-Kibble theory of gravity generates gravitational repulsion at very high densities, which prevents a singularity in a black hole and may create there a new universe. We show…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-22 Shantanu Desai , Nikodem J. Poplawski

The new scale-covariant formulation of the Dirac's Large Number Hypothesis (LNH) is proposed. The basic equations of LNH are formulated in the scale-covariant and "G-invariant" (invariant on the transformation law for G) form. On the basis…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Alexander Rogachev