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There are explored off-diagonal deformations of "prime" metrics in Einstein gravity (for instance, for wormhole configurations) into "target" exact solutions in f(R,T)-modified and massive/ bi-metric gravity theories. The new classes of…

General Relativity and Quantum Cosmology · Physics 2014-03-25 Sergiu I. Vacaru

We find general parameterizations for generic off-diagonal spacetime metrics and matter sources in general relativity (GR) and modified gravity theories when the field equations decouple with respect to certain types of nonholonomic frames…

General Relativity and Quantum Cosmology · Physics 2014-12-25 Tamara Gheorghiu , Olivia Vacaru , Sergiu I. Vacaru

Geometric methods for constructing exact solutions of motion equations with first order $\alpha ^{\prime}$ corrections to the heterotic supergravity action implying a non-trivial Yang-Mills sector and six dimensional, 6-d, almost-K\"ahler…

High Energy Physics - Theory · Physics 2017-01-16 Sergiu I. Vacaru , Klee Irwin

We summarize some our recent results on encoding exact solutions of field equations in Einstein and modified gravity theories into solitonic hierarchies derived for nonholonomic curve flows with associated bi-Hamilton structure. We argue…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Sergiu I. Vacaru

The aims of this work are 1) to sketch a proof that there are such parameterizations of the local frame and canonical connection structures when the gravitational field equations in f(R,T)-modified gravity, MG, can be integrated in generic…

General Relativity and Quantum Cosmology · Physics 2014-01-10 Sergiu I. Vacaru

A generalized geometric method is developed for constructing exact solutions of gravitational field equations in Einstein theory and generalizations. First, we apply the formalism of nonholonomic frame deformations (formally considered for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sergiu I. Vacaru

We use an important decoupling property of gravitational field equations in the general relativity theory and modifications, written with respect to nonholonomic frames with 2+2 spacetime decomposition. This allows us to integrate the…

General Physics · Physics 2013-03-18 Sergiu I. Vacaru

We outline a new geometric method of constructing exact solutions of gravitational field equations parametrized by generic off-diagonal metrics, anholonomic frames and possessing, in general, nontrivial torsion and nonmetricity. The…

Differential Geometry · Mathematics 2007-05-23 Sergiu I. Vacaru

It is shown that in the static, spherically symmetric spacetime the problem of metric f(R) gravity coupled with non-linear Yang-Mills (YM) field constructed from the Wu-Yang ansatz as source, can be solved in all dimensions. By…

General Relativity and Quantum Cosmology · Physics 2011-09-26 S. Habib Mazharimousavi , M. Halilsoy

The gravitational field equations in general relativity (GR) consist of a sophisticated system of nonlinear partial differential equations. Solving such equations in some generic off-diagonal forms is usually a hard analytic or numeric…

General Relativity and Quantum Cosmology · Physics 2025-08-18 Sergiu I. Vacaru , Elşen V. Veliev

We argue that generic off-diagonal vacuum and nonvacuum solutions for Einstein manifolds mimic physical effects in modified gravity theories (MGTs) and encode certain models of the $f(R,T,...)$, Ho\v{r}ava type with dynamical Lorentz…

High Energy Physics - Theory · Physics 2015-02-25 Tamara Gheorghiu , Olivia Vacaru , Sergiu Vacaru

We present new classes of exact solutions with noncommutative symmetries constructed in vacuum Einstein gravity (in general, with nonzero cosmological constant), five dimensional (5D) gravity and (anti) de Sitter gauge gravity. Such…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Sergiu I. Vacaru

We re-investigate how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates can be constructed in massive and f-modified gravity using the anholonomic frame deformation method. There are constructed…

General Relativity and Quantum Cosmology · Physics 2015-05-06 Sergiu I. Vacaru

We show how the Einstein equations with cosmological constant (and/or various types of matter field sources) can be integrated in a very general form following the anholonomic deformation method for constructing exact solutions in four and…

General Physics · Physics 2017-10-19 Sergiu I. Vacaru

Using our anholonomic frame deformation method, we show how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates and undergoing a phase of ultra-slow contraction can be constructed in massive…

High Energy Physics - Theory · Physics 2017-06-05 Sergiu I. Vacaru

We prove that the Einstein equations can be solved in a very general form for arbitrary spacetime dimensions and various types of vacuum and non-vacuum cases following a geometric method of anholonomic frame deformations for constructing…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Sergiu I. Vacaru

A classification of gravitating Yang--Mills systems in all dimensions is presented. These systems are set up so that they support finite energy solutions. Both regular and black hole solutions are considered, the former being the limit of…

General Relativity and Quantum Cosmology · Physics 2009-07-10 Eugen Radu , D. H. Tchrakian

Many papers on modified gravity theories (MGTs), and metric-affine geometry have been published. New classes of black hole (BH), wormhole (WH), and cosmological solutions involving nonmetricity and torsion fields were constructed.…

General Physics · Physics 2025-06-13 Sergiu I. Vacaru

Several exact, cylindrically symmetric solutions to Einstein's vacuum equations are given. These solutions were found using the connection between Yang-Mills theory and general relativity. Taking known solutions of the Yang-Mills equations…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Douglas Singleton

We elaborate on the anholonomic frame deformation method, AFDM, for constructing exact solutions with quasiperiodic structure in modified gravity theories, MGTs, and general relativity, GR. Such solutions are described by generic…

General Physics · Physics 2018-05-29 Laurenţiu Bubuianu , Sergiu I. Vacaru
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