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In this work we construct and analyze exact solutions describing Ricci flows and nonholonomic deformations of four dimensional (4D) Taub-NUT spacetimes. It is outlined a new geometric techniques of constructing Ricci flow solutions. Some…

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

In a number of physically important cases, the nonholonomically (nonintegrable) constrained Ricci flows can be modelled by exact solutions of Einstein equations with nonhomogeneous (anisotropic) cosmological constants. We develop two…

Mathematical Physics · Physics 2009-02-17 Sergiu I. Vacaru

We provide a proof that nonholonomically constrained Ricci flows of (pseudo) Riemannian metrics positively result into nonsymmetric metrics (as explicit examples, we consider flows of some physically valuable exact solutions in general…

General Relativity and Quantum Cosmology · Physics 2009-02-18 Sergiu I. Vacaru

We study Ricci flows of some classes of physically valuable solutions in Einstein and string gravity. The anholonomic frame method is applied for generic off-diagonal metric ansatz when the field/ evolution equations are transformed into…

Mathematical Physics · Physics 2009-05-05 Sergiu I. Vacaru

The Ricci flow is a parabolic evolution equation in the space of Riemannian metrics of a smooth manifold. To some extent, Einstein equations give rise to a similar hyperbolic evolution. The present text is an introductory exposition to…

Differential Geometry · Mathematics 2011-06-27 Abdelghani Zeghib

In this paper, it is elaborated the theory the Ricci flows for manifolds enabled with nonintegrable (nonholonomic) distributions defining nonlinear connection structures. Such manifolds provide a unified geometric arena for nonholonomic…

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

This is the second paper in a series of works devoted to nonholonomic Ricci flows. By imposing non-integrable (nonholonomic) constraints on the Ricci flows of Riemannian metrics we can model mutual transforms of generalized Finsler-Lagrange…

Differential Geometry · Mathematics 2008-11-26 Sergiu I. Vacaru

B List has recently studied a geometric flow whose fixed points correspond to static Ricci flat spacetimes. It is now known that this flow is in fact Ricci flow modulo pullback by a certain diffeomorphism. We use this observation to…

General Relativity and Quantum Cosmology · Physics 2009-02-20 M M Akbar , E Woolgar

We find exact solutions describing Ricci flows of four dimensional pp-waves nonlinearly deformed by two/three dimensional solitons. Such solutions are parametrized by five dimensional metrics with generic off-diagonal terms and connections…

High Energy Physics - Theory · Physics 2009-11-11 Sergiu I. Vacaru

We give a global picture of the Ricci flow on the space of three-dimensional, unimodular, nonabelian metric Lie algebras considered up to isometry and scaling. The Ricci flow is viewed as a two-dimensional dynamical system for the evolution…

Differential Geometry · Mathematics 2015-10-22 David Glickenstein , Tracy L. Payne

We investigate gravity models emerging from nonholonomic (subjected to non-integrable constraints) Ricci flows. Considering generalizations of G. Perelman's entropy functionals, relativistic geometric flow equations, nonholonomic Ricci…

General Physics · Physics 2020-11-30 Iuliana Bubuianu , Sergiu I. Vacaru , Elşen Veli Veliev

The geometric constructions are elaborated on (semi) Riemannian manifolds and vector bundles provided with nonintegrable distributions defining nonlinear connection structures induced canonically by metric tensors. Such spaces are called…

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

We consider the Ricci flow equation for invariant metrics on compact and connected homogeneous spaces whose isotropy representation decomposes into two irreducible inequivalent summands. By studying the corresponding dynamical system, we…

Differential Geometry · Mathematics 2012-09-17 Maria Buzano

We give the global picture of the normalized Ricci flow on generalized flag manifolds with two or three isotropy summands. The normalized Ricci flow for these spaces descents to a parameter depending system of two or three ordinary…

Differential Geometry · Mathematics 2011-05-25 Stavros Anastassiou , Ioannis Chrysikos

In order to resolve the cosmological constant problem, the notion of reference frame is re-examined at the quantum level. By using a quantum non-linear sigma model (Q-NLSM), a theory of quantum spacetime reference frame (QSRF) is proposed.…

General Physics · Physics 2021-02-03 M. J. Luo

Imposing non-integrable constraints on Ricci flows of (pseudo) Riemannian metrics we model mutual transforms to, and from, non-Riemannian spaces. Such evolutions of geometries and physical theories can be modelled for nonholonomic manifolds…

Mathematical Physics · Physics 2013-05-20 Sergiu I. Vacaru

A recent article uncovered a surprising dynamical mechanism at work within the (vacuum) Einstein `flow' that strongly suggests that many closed 3-manifolds that do not admit a locally homogeneous and isotropic metric \textit{at all} will…

General Relativity and Quantum Cosmology · Physics 2019-03-04 Vincent Moncrief , Puskar Mondal

A cosmological model describing the evolution of $n$ Einstein spaces $(n>1)$ with $m$-component perfect-fluid matter is considered. When all spaces are Ricci-flat and for any $\alpha$-th component the pressures in all spaces are…

General Relativity and Quantum Cosmology · Physics 2011-04-20 V. D. Ivashchuk , V. N. Melnikov

We prove nonlinear stability for a large class of solutions to the Einstein equations with a positive cosmological constant and compact spatial topology in arbitrary dimensions, where the spatial metric is Einstein with either positive or…

Differential Geometry · Mathematics 2018-05-01 David Fajman , Klaus Kroencke

We study noncommutative Ricci flow in a finite dimensional representation of a noncommutative torus. It is shown that the flow exists and converges to the flat metric. We also consider the evolution of entropy and a definition of scalar…

Mathematical Physics · Physics 2014-02-10 Rocco Duvenhage
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