Results 31 to 40 of about 156,624 (168)
Dynamical Signature: Complex Manifolds, Gauge Fields and Non-Flat Tangent Space
Universe, 2022 Theoretical possibilities of models of gravity with dynamical signature are discussed. The different scenarios of the signature change are proposed in the framework of Einstein-Cartan gravity.
Sergey Bondarenko
doaj +1 more source
Ricci soliton and Ricci almost soliton within the framework of Kenmotsu manifold
Karpatsʹkì Matematičnì Publìkacìï, 2019 First, we prove that if the Reeb vector field $\xi$ of a Kenmotsu manifold $M$ leaves the Ricci operator $Q$ invariant, then $M$ is Einstein. Next, we study Kenmotsu manifold whose metric represents a Ricci soliton and prove that it is expanding ...
A. Ghosh
doaj +1 more source
Projective compactifications and Einstein metrics [PDF]
Journal für die reine und angewandte Mathematik (Crelles Journal), 2014 Abstract For complete affine manifolds we introduce a definition of compactification based on the projective differential geometry (i.e. geodesic path data) of the given connection. The definition of projective compactness involves a real parameter α called the order of projective compactness.
Cap, Andreas, Gover, A. Rod
openaire +4 more sources
Rigidity of Weak Einstein-Randers Spaces [PDF]
Sahand Communications in Mathematical AnalysisThe Randers metrics are popular metrics similar to the Riemannian metrics, frequently used in physical and geometric studies. The weak Einstein-Finsler metrics are a natural generalization of the Einstein-Finsler metrics.
Behnaz Lajmiri +2 more
doaj +1 more source
Metrics With Vanishing Quantum Corrections
, 2008 We investigate solutions of the classical Einstein or supergravity equations that solve any set of quantum corrected Einstein equations in which the Einstein tensor plus a multiple of the metric is equated to a symmetric conserved tensor $T_{\mu \nu ...
A A Coley +21 more
core +1 more source
Spectral metric and Einstein functionals
Advances in Mathematics, 2023 We define bilinear functionals of vector fields and differential forms, the densities of which yield the metric and Einstein tensors on even-dimensional Riemannian manifolds. We generalise these concepts in non-commutative geometry and, in particular, we prove that for the conformally rescaled geometry of the noncommutative two-torus the Einstein ...
Ludwik Dabrowski +2 more
openaire +3 more sources
On Bochner Flat Kähler B-Manifolds
Axioms, 2023 We obtain on a Kähler B-manifold (i.e., a Kähler manifold with a Norden metric) some corresponding results from the Kählerian and para-Kählerian context concerning the Bochner curvature. We prove that such a manifold is of constant totally real sectional
Cornelia-Livia Bejan +2 more
doaj +1 more source
Geometry for the accelerating universe [PDF]
, 2006 The Lorentzian spacetime metric is replaced by an area metric which naturally emerges as a generalized geometry in quantum string and gauge theory. Employing the area metric curvature scalar, the gravitational Einstein-Hilbert action is re-interpreted as
C. Rovelli +5 more
core +2 more sources
European Physical Journal C: Particles and Fields, 2021 We construct an approximate solution to the cosmological perturbation theory around Einstein–de Sitter background up to the fourth-order perturbations. This could be done with the help of the specific symmetry condition imposed on the metric, from which ...
Szymon Sikora, Krzysztof Głód
doaj +1 more source
Distances of qubit density matrices on Bloch sphere
, 2011 We recall the Einstein velocity addition on the open unit ball $\B$ of $\R^{3}$ and its algebraic structure, called the Einstein gyrogroup. We establish an isomorphism between the Einstein gyrogroup on $\B$ and the set of all qubit density matrices ...
Einstein A. +3 more
core +1 more source