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To study asymptotic structures, we regularize Einstein's field equations by means of conformal transformations. The conformal factor is chosen so that it carries a dimensional scale that captures crucial asymptotic features. By choosing a…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Niklas Rohr , Claes Uggla

In this paper we apply the anholonomic frames method developed in refs. [1-4] to construct and study anisotropic vacuum field configurations in 5D gravity. Starting with an off--diagonal 5D metric, parameterized in terms of several ansatz…

High Energy Physics - Theory · Physics 2009-11-07 Sergiu I. Vacaru , D. Singleton

We develop the method of anholonomic frames with associated nonlinear connection (in brief, N--connection) structure and show explicitly how geometries with local anisotropy (various type of Finsler--Lagrange--Cartan--Hamilton geometry) can…

High Energy Physics - Theory · Physics 2007-05-23 Sergiu I. Vacaru

New geometric and analytic methods for generating exact and parametric solutions in generalized Einstein-Finsler like gravity theories and nonholonomic Ricci soliton models are reviewed and developed. We show how generalizations of the…

General Physics · Physics 2019-03-12 Laurenţiu Bubuianu , Sergiu I. Vacaru

A systematic study of deformations of four-dimensional Einsteinian space-times embedded in a pseudo-Euclidean space $E^N$ of higher dimension is presented. Infinitesimal deformations, seen as vector fields in $E^N$, can be divided in two…

General Relativity and Quantum Cosmology · Physics 2008-02-01 Richard Kerner , Salvatore Vitale

The goal of this work is to elaborate on new geometric methods of constructing exact and parametric quasiperiodic solutions for anamorphic cosmology models in modified gravity theories, MGTs, and general relativity, GR. There exist…

General Relativity and Quantum Cosmology · Physics 2017-10-24 Marcelo M. Amaral , Raymond Aschheim , Laurenţiu Bubuianu , Klee Irwin , Sergiu I. Vacaru , Daniel Woolridge

Exact solutions to the Einstein field equations may be generated from already existing ones (seed solutions), that admit at least one Killing vector. In this framework, a space of potentials is introduced. By the use of symmetries in this…

General Relativity and Quantum Cosmology · Physics 2016-03-16 I. G. Contopoulos , F. P. Esposito , K. Kleidis , D. B. Papadopoulos , L. Witten

We study new classes of generic off-diagonal and diagonal cosmological solutions for effective Einstein equations in modified gravity theories, MGTs, with modified dispersion relations, MDRs, encoding possible violations of (local) Lorentz…

General Physics · Physics 2021-06-02 Panayiotis Stavrinos , Sergiu I. Vacaru

We construct solutions of higher-dimensional Einstein gravity coupled to nonlinear $\sigma$-model with cosmological constant. The $\sigma$-model can be perceived as exterior configuration of a spontaneously-broken $SO(D-1)$ global…

General Relativity and Quantum Cosmology · Physics 2017-08-30 Ilham Prasetyo , Handhika S. Ramadhan

A class of integrable models of 1+1 dimensional dilaton gravity coupled to scalar and electromagnetic fields is obtained and explicitly solved. More general models are reduced to 0+1 dimensional Hamiltonian systems, for which two integrable…

High Energy Physics - Theory · Physics 2009-10-30 A. T. Filippov

Certain off-diagonal vacuum and nonvacuum configurations in Einstein gravity can mimic physical effects of modified gravitational theories of $ f(R,T,R_{\mu\nu}T^{\mu\nu})$ type. We prove this statement by constructing exact and approximate…

Mathematical Physics · Physics 2015-06-30 Emilio Elizalde , Sergiu I. Vacaru

We obtain a new family of exact vacuum solutions to quadratic gravity that describe pp-waves with two-dimensional wave surfaces that can have any prescribed constant curvature. When the wave surfaces are flat we recover the Peres waves…

General Relativity and Quantum Cosmology · Physics 2024-12-19 Sjors Heefer , Lorens F. Niehof , Andrea Fuster

We show that a geometric techniques can be elaborated and applied for constructing generic off-diagonal exact solutions in $f(R,T)$--modified gravity for systems of gravitational-Yang-Mills-Higgs equations. The corresponding classes of…

General Relativity and Quantum Cosmology · Physics 2014-11-12 Sergiu I. Vacaru , Elsen Veli Veliev , Enis Yazici

We find new classes of exact solutions to the Einstein-Maxwell system of equations for a charged sphere with a particular choice of the electric field intensity and one of the gravitational potentials. The condition of pressure isotropy is…

General Relativity and Quantum Cosmology · Physics 2009-03-19 K. Komathiraj , S. D. Maharaj

We study a noncommutative deformation of general relativity where the gravitational field is described by a matrix-valued symmetric two-tensor field. The equations of motion are derived in the framework of this new theory by varying a…

General Relativity and Quantum Cosmology · Physics 2011-02-17 Guglielmo Fucci , Ivan G. Avramidi

We study nonlinear gravity theories in both the metric and the Palatini (metric-affine) formalisms. The nonlinear character of the gravity lagrangian in the metric formalism causes the appearance of a scalar source of matter in Einstein's…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Gonzalo J. Olmo , William Komp

We argue that the Einstein gravity theory can be reformulated in almost Kahler (nonsymmetric) variables with effective symplectic form and compatible linear connection uniquely defined by a (pseudo) Riemannian metric. A class of…

General Relativity and Quantum Cosmology · Physics 2009-07-24 Sergiu I. Vacaru

In this work a study of the gravity is made using Einstein's equation in the post-Newtonian approach. This is a method to linearise the General Relativity indicated to treat non-relativistic objects. It enables us to construct, from…

General Relativity and Quantum Cosmology · Physics 2013-04-29 I. C. Jardim , R. R. Landim

Over the last seventy years, many Finsler-type geometric and modified gravity theories have been elaborated. They have been formulated in terms of different classes of Finsler generating functions, metric and nonmetric structures, nonlinear…

Mathematical Physics · Physics 2026-03-19 Sergiu I. Vacaru

We discuss dynamical aspects of gravitational plane waves in Einstein theory with massless scalar fields. The general analytic solution describes colliding gravitational waves with constant polarization, which interact with scalar waves…

General Relativity and Quantum Cosmology · Physics 2018-10-17 Jorge G. Russo