Exhaustive integration and a single expression for the general solution of the typeDvacuum and electrovac field equations with cosmological constant for a nonsingular aligned Maxwell field

1984 ◽  
Vol 25 (6) ◽  
pp. 1955-1972 ◽  
Author(s):  
R. Debever ◽  
N. Kamran ◽  
R. G. McLenaghan
Keyword(s):  
General Solution ◽  
Cosmological Constant ◽  
Maxwell Field ◽  
Field Equations

scholarly journals Spherically Symmetric Charged Dust Distribution in General Relativity. I. General Solution

1980 ◽  
Vol 33 (4) ◽  
pp. 765 ◽  
Author(s):  
BK Nayak
Keyword(s):  
General Relativity ◽  
General Solution ◽  
Charge Density ◽  
Mass Density ◽  
Maxwell Field ◽  
Charged Dust ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Mathematical Condition ◽  
Dust Distribution

The Einstein-Maxwell field equations characterizing a spherically symmetric charged dust distnbution are solved exactly without imposing any mathematical condition on them. The solution is expressed in terms of two arbitrary variables and these can be chosen to correspond to an arbitrary ratio of charge density to mass density, thus allowing the possibility of understanding the interior of the horizon in a more precise manner.

scholarly journals Black hole solutions in Rastall theory

2017 ◽  
Vol 95 (12) ◽  
pp. 1253-1256 ◽  
Author(s):  
Y. Heydarzade ◽  
H. Moradpour ◽  
F. Darabi
Keyword(s):  
Black Hole ◽  
General Solution ◽  
Symmetric Space ◽  
Cosmological Constant ◽  
Black Hole Solution ◽  
Ad Hoc ◽  
Vacuum Field ◽  
De Sitter ◽  
Field Equations ◽  
Black Hole Solutions

The Reissner–Nordström black hole solution in a generic cosmological constant background in the context of Rastall gravity is obtained. It is shown that the cosmological constant arises naturally from the consistency of the non-vacuum field equations of the Rastall theory for a spherical symmetric space–time, rather than its ad hoc introduction in the usual Einstein and Einstein–Maxwell field equations. The usual Reissner–Nordström, Schwarzschild, and Schwarzschild – (anti-)de Sitter black hole solutions in the framework of this theory are also addressed as the special independent subclasses of the obtained general solution.

Cosmological constant Λ in f(R,T) modified gravity

2016 ◽  
Vol 13 (05) ◽  
pp. 1650058 ◽  
Author(s):  
Gyan Prakash Singh ◽  
Binaya Kumar Bishi ◽  
Pradyumn Kumar Sahoo
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Modified Gravity ◽  
Bianchi Type ◽  
Field Equations ◽  
Type Iii ◽  
Expansion Scalar ◽  
Modified Theory Of Gravity ◽  
Shear Scalar ◽  
Modified Theory

In this paper, we have studied the Bianchi type-III cosmological model in the presence of cosmological constant in the context of [Formula: see text] modified theory of gravity. Here, we have discussed two classes of [Formula: see text] gravity, i.e. [Formula: see text] and [Formula: see text]. In both classes, the modified field equations are solved by the relation expansion scalar [Formula: see text] that is proportional to shear scalar [Formula: see text] which gives [Formula: see text], where [Formula: see text] and [Formula: see text] are metric potentials. Also we have discussed some physical and kinematical properties of the models.

On a symbolic algebra for Hencky-Prandtl nets

1983 ◽  
Vol 94 (2) ◽  
pp. 341-350
Author(s):  
R. Hill
Keyword(s):  
General Solution ◽  
Boundary Value Problems ◽  
Classical Theory ◽  
Systematic Approach ◽  
Standard Technique ◽  
Field Equations ◽  
Infinite Matrices ◽  
Symbolic Algebra ◽  
Series Representations ◽  
Plane Deformations

AbstractIn the classical theory of plane deformations in isotropic plastic media, the field equations are hyperbolic and the orthogonal families of characteristics are known as Hencky-Prandtl nets. Their distinctive geometry has been given symbolic expression by Collins (1968), in an algebra of infinite matrices associated with canonical series representations of the general solution. This has become the standard technique when investigating boundary-value problems, both analytically and numerically. The basic framework of the algebra is here reorganized and developed. A systematic approach then leads to new identities which are shown to be fundamental in the algebraic hierarchy.

scholarly journals GENERALIZED EINSTEIN–MAXWELL FIELD EQUATIONS IN THE PALATINI FORMALISM

2013 ◽  
Vol 22 (04) ◽  
pp. 1350017 ◽  
Author(s):  
GINÉS R. PÉREZ TERUEL
Keyword(s):  
Electromagnetic Field ◽  
Algebraic Equation ◽  
Ricci Tensor ◽  
Maxwell Equations ◽  
Natural Generalization ◽  
New Method ◽  
Maxwell Field ◽  
Field Equations ◽  
Palatini Formalism

We derive a new set of field equations within the framework of the Palatini formalism. These equations are a natural generalization of the Einstein–Maxwell equations which arise by adding a function [Formula: see text], with [Formula: see text] to the Palatini Lagrangian f(R, Q). The result we obtain can be viewed as the coupling of gravity with a nonlinear extension of the electromagnetic field. In addition, a new method is introduced to solve the algebraic equation associated to the Ricci tensor.

scholarly journals TRAVERSABLE WORMHOLES IN (2+1) AND (3+1) DIMENSIONS WITH A COSMOLOGICAL CONSTANT

1995 ◽  
Vol 04 (02) ◽  
pp. 231-245 ◽  
Author(s):  
M.S.R. DELGATY ◽  
R.B. MANN
Keyword(s):  
Energy Density ◽  
Cosmological Constant ◽  
Positive Energy ◽  
Mass Energy ◽  
Field Equations ◽  
Dimensional Solution ◽  
Partial Stability ◽  
Traversable Wormholes ◽  
Spacetime Curvature ◽  
Radial Tension

Macroscopic traversable wormhole solutions to Einstein’s field equations in (2+1) and (3+1) dimensions with a cosmological constant are investigated. Ensuring traversability severely constrains the material used to generate the wormhole’s spacetime curvature. Although the presence of a cosmological constant modifies to some extent the type of matter permitted [for example it is possible to have a positive energy density for the material threading the throat of the wormhole in (2+1) dimensions], the material must still be “exotic,” that is matter with a larger radial tension than total mass-energy density multiplied by c2. Two specific solutions are applied to the general cases and a partial stability analysis of a (2+1) dimensional solution is explored.

scholarly journals Wormholes in Wyman's solution

2014 ◽  
Vol 23 (11) ◽  
pp. 1450086 ◽  
Author(s):  
J. B. Formiga ◽  
T. S. Almeida
Keyword(s):  
Scalar Field ◽  
General Solution ◽  
Detailed Analysis ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Human Beings ◽  
Einstein Field Equations ◽  
Field Equations

The most general solution of the Einstein field equations coupled with a massless scalar field is known as Wyman's solution. This solution is also present in the Brans–Dicke theory and, due to its importance, it has been studied in detail by many authors. However, this solutions has not been studied from the perspective of a possible wormhole. In this paper, we perform a detailed analysis of this issue. It turns out that there is a wormhole. Although we prove that the so-called throat cannot be traversed by human beings, it can be traversed by particles and bodies that can last long enough.

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