Results 21 to 30 of about 193 (38)
Flat deformation of a spacetime admitting two Killing fields [PDF]
, 2010 It is shown that given an analytic Lorentzian metric on a 4-manifold, $g$, which admits two Killing vector fields, then it exists a local deformation law $\eta = a g + b H$, where $H$ is a 2-dimensional projector, such that $\eta$ is flat and admits the ...
Choquet-Bruhat Y +9 more
core +3 more sources
Intrinsic Spectral Geometry of the Kerr-Newman Event Horizon
, 2006 We uniquely and explicitly reconstruct the instantaneous intrinsic metric of the Kerr-Newman Event Horizon from the spectrum of its Laplacian. In the process we find that the angular momentum parameter, radius, area; and in the uncharged case, mass, can ...
Martin Engman +4 more
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Critical Robertson-Walker universes [PDF]
, 2019 The integral of the energy density function $\mathfrak m$ of a closed Robertson-Walker (RW) spacetime with source a perfect fluid and cosmological constant $\Lambda$ gives rise to an action functional on the space of scale functions of RW spacetime ...
Eshkobilov, Olimjon +2 more
core +2 more sources
Exact Fermi coordinates for a class of spacetimes
, 2009 We find exact Fermi coordinates for timelike geodesic observers for a class of spacetimes that includes anti-de Sitter spacetime, de Sitter spacetime, the constant density interior Schwarzschild spacetime with positive, zero, and negative cosmological ...
David Klein +3 more
core +1 more source
A Special Universe and its Massless Scalar Field Mathematical Structure
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria MatematicaThe present paper highlights an exotic universe having a metric which is partially suggested by the metric of an universe without time seen in [2]. The new metric is globally defined and depends on an exotic matter created by some classical waves.
Boskoff Wladimir-Georges +1 more
doaj +1 more source
Nonholonomic Ricci Flows and Running Cosmological Constant: I. 4D Taub-NUT Metrics [PDF]
, 2006 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.
Astefanesei D. +8 more
core +3 more sources
LRS Bianchi type-I cosmological model with constant deceleration parameter in $f(R,T)$ gravity
, 2017 A spatially homogeneous anisotropic LRS Bianchi type-I cosmological model is studied in $f(R,T)$ gravity with a special form of Hubble's parameter, which leads to constant deceleration parameter.
Bishi, Binaya K. +3 more
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Fractional Curve Flows and Solitonic Hierarchies in Gravity and Geometric Mechanics
, 2011 Methods from the geometry of nonholonomic manifolds and Lagrange-Finsler spaces are applied in fractional calculus with Caputo derivatives and for elaborating models of fractional gravity and fractional Lagrange mechanics.
Dumitru Baleanu +3 more
core +1 more source
Generating potentials via difference equations
, 2006 The condition for pressure isotropy, for spherically symmetric gravitational fields with charged and uncharged matter, is reduced to a recurrence equation with variable, rational coefficients.
Debnath +10 more
core +1 more source
, 2003 We present the method of group foliation for constructing non-invariant solutions of partial differential equations on an important example of the Boyer-Finley equation from the theory of gravitational instantons.
Sheftel, M. B.
core +1 more source