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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

A new technique is presented for modifying the Einstein evolution equations off the constraint hypersurface. With this approach the evolution equations for the constraints can be specified freely. The equations of motion for the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 J. David Brown , Lisa L. Lowe

A new method of construction of integral varieties of Einstein equations in three dimensional (3D) and 4D gravity is presented whereby, under corresponding redefinition of physical values with respect to anholonomic frames of reference with…

General Relativity and Quantum Cosmology · Physics 2010-02-03 Sergiu I. Vacaru

A broad class of generalized Einstein's gravity can be cast into Einstein's gravity with a minimally coupled scalar field using suitable conformal rescaling of the metric. Using this conformal equivalence between the theories, we derive the…

General Relativity and Quantum Cosmology · Physics 2011-09-30 J. Hwang

The fundamental field equations in modified gravity (including general relativity; massive and bimetric theories; Ho\vrava-Lifshits, HL; Einstein--Finsler gravity extensions etc) posses an important decoupling property with respect to…

General Physics · Physics 2014-10-30 Sergiu I. Vacaru

This article is a status report on the Anholonomic Frame and Connection Deformation Method, AFCDM, for constructing generic off-diagonal exact and parametric solutions in general relativity, GR, relativistic geometric flows, and modified…

General Relativity and Quantum Cosmology · Physics 2025-10-07 Laurenţiu Bubuianu , Julia O. Seti , Douglas Singleton , Panayiotis Stavrinos , Sergiu I. Vacaru , Elşen Veli Veliev

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

It is well known that the Einstein-Hilbert action in two dimensions is topological and yields an identically vanishing Einstein tensor. Consequently one is faced with difficulties when formulating a non-trivial gravity model. We present a…

General Relativity and Quantum Cosmology · Physics 2024-06-10 Christian G. Boehmer , Erik Jensko

Following a bi-cylindrical model of geometrical dynamics, in the present study we show that Einstein gravitational equation leads to bi-geodesic description in an extended symmetrical time-space which fit Hubble expansion in a "microscopic"…

General Physics · Physics 2016-05-13 Vo Van Thuan

The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Vitor Cardoso , Leonardo Gualtieri , Carlos Herdeiro , Ulrich Sperhake

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

In Einstein's general relativity, with its nonlinear field equations, the discoveries and analyzes of various specific explicit solutions made a great impact on understanding many of the unforeseen features of the theory. Some solutions…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jiri Bicak

We get the general static, spherically symmetric solutions of the d-dimensional Einstein-Maxwell-Dilaton theories by dimensionally reducing them to a class of 2-dimensional dilaton gravity theories. By studying the symmetries of the actions…

High Energy Physics - Theory · Physics 2010-11-19 Youngjai Kiem , Dahl Park

We construct a new class of exact solutions describing spacetimes possessing Lie algebroid symmetry. They are described by generic off-diagaonal 5D metrics embedded in bosonic string gravity and possess nontrivial limits to the Einstein…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Sergiu I. Vacaru

For (2+2)-dimensional nonholonomic distributions, the physical information contained into a spacetime (pseudo) Riemannian metric can be encoded equivalently into new types of geometric structures and linear connections constructed as…

General Relativity and Quantum Cosmology · Physics 2010-04-08 Sergiu I. Vacaru

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

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 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

We study the Riemann geometric approach to be aimed at unifying soliton systems. The general two-dimensional Einstein equation with constant scalar curvature becomes an integrable differential equation. We show that such Einstein equation…

Exactly Solvable and Integrable Systems · Physics 2019-09-24 Masahito Hayashi , Kazuyasu Shigemoto , Takuya Tsukioka

The cosmological constant and its phenomenology remain among the greatest puzzles in theoretical physics. We review how modifications of Einstein's general relativity could alleviate the different problems associated with it that result…

General Relativity and Quantum Cosmology · Physics 2022-10-14 The FADE Collaboration , Heliudson Bernardo , Benjamin Bose , Guilherme Franzmann , Steffen Hagstotz , Yutong He , Aliki Litsa , Florian Niedermann