共查询到20条相似文献，搜索用时 31 毫秒
1.
In this paper, using the energy definition in MØller’s tetrad theory of gravity we calculate the total energy of the universe in Bianchi-type I cosmological models which includes both the matter and gravitational fields. The total energy is found to be zero and this result agrees with a previous works of Banerjee and Sen who investigated this problem using the general relativity version of the Einstein energy-momentum complex and Xulu who investigated same problem using the general relativity versions of the Landau and lifshitz, Papapetrou and Weinberg’s energy-momentum complexes. The result that total energy of the universe in Bianchi-type I universes is zero supports the viewpoint of Tryon. 相似文献
2.
3.
4.
Mustafa Saltı 《Astrophysics and Space Science》2006,306(4):201-204
We use the teleparallel geometry analog of the Møller energy-momentum complex to calculate the energy distribution (due to matter plus field including gravity) of a charged black hole solution in heterotic string theory. We find the same energy distribution as obtained by Gad who investigated the same problem by using the Møller energy-momentum complex in general relativity. The total energy depends on the black hole mass M and charge Q. The energy obtained is also independent of the teleparallel dimensionless coupling constant, which means that it is valid not only in the teleparallel equivalent of general relativity, but also in any teleparallel model. Furthermore, our results also sustains (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime and (b) the viewpoint of Lessner that the Møller energy-momentum complex is a powerful concept of energy and momentum. 相似文献
5.
Ngangbam Ishwarchandra N. Ibohal K. Yugindro Singh 《Astrophysics and Space Science》2014,353(2):633-639
In this paper we present an exact solution of Einstein’s field equations describing the Schwarzschild black hole in dark energy background. It is also regarded as an embedded solution that the Schwarzschild black hole is embedded into the dark energy space producing Schwarzschild-dark energy black hole. It is found that the space-time geometry of Schwarzschild-dark energy solution is non-vacuum Petrov type D in the classification of space-times. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor of the Schwarzschild-dark energy solution. We also find that the energy-momentum tensor of the Schwarzschild-dark energy solution violates the strong energy condition due to the negative pressure leading to a repulsive gravitational force of the matter field in the space-time. It is shown that the time-like vector field for an observer in the Schwarzschild-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity and the area of the horizons for the Schwarzschild-dark energy black hole. 相似文献
6.
Time-dependent wormhole solutions are found which evolve on inhomogeneous spherically symmetric space time. By using a constraint
on energy-momentum tensor, solutions are derived from Einstein’s equations with cosmological constant. 相似文献
7.
8.
In this paper we present a class of non-stationary solutions of Einstein’s field equations describing embedded Vaidya-de Sitter black holes with a cosmological variable function Λ(u). The Vaidya-de Sitter black hole is interpreted as the radiating Vaidya black hole is embedded into the non-stationary de Sitter space with variable Λ(u). The energy-momentum tensor of the Vaidya-de Sitter black hole is expressed as the sum of the energy-momentum tensors of the Vaidya null fluid and that of the non-stationary de Sitter field, and satisfies the energy conservation law. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor. We find the violation of the strong energy condition due to the negative pressure and leading to a repulsive gravitational force of the matter field associated with Λ(u) in the space-time. We also find that the time-like vector field for an observer in the Vaidya-de Sitter space is expanding, accelerating, shearing and non-rotating. It is also found that the space-time geometry of non-stationary Vaidya-de Sitter solution with variable Λ(u) is Petrov type D in the classification of space-times. We also find the Vaidya-de Sitter black hole radiating with a thermal temperature proportional to the surface gravity and entropy also proportional to the area of the cosmological black hole horizon. 相似文献
9.
10.
We discuss (n+1)-dimensional dynamical wormholes in an evolving cosmological background with a throat expanding with time. These solutions are examined in the general relativity framework. A linear relation between diagonal elements of an anisotropic energy-momentum tensor is used to obtain the solutions. The energy-momentum tensor elements approach the vacuum case when we are far from the central object for one class of solutions. Finally, we discuss the energy-momentum tensor which supports this geometry, taking into account the energy conditions. 相似文献
11.
Gamal G. L. Nashed 《Astrophysics and Space Science》2010,330(1):173-181
We apply the energy-momentum tensor which is coordinate independent to calculate the energy content of the axisymmetric solutions.
Our results are compared with what have been obtained before within the framework of Einstein general relativity and M?ller’s
tetrad theory of gravitation. 相似文献
12.
13.
Can Battal Kılınç 《Astrophysics and Space Science》2004,289(1-2):103-109
Einstein's equations with variable gravitational and cosmological constants are considered in the presence of a perfect fluid for the anizotropic Bianchi I universe in a way which conserving the energy-momentum tensor. Two solutions are found, one of which the cosmological term varies inversely with power law of time. The other of which cosmological term is constant. 相似文献
14.
Harald H. Soleng 《Astrophysics and Space Science》1987,139(1):13-19
The field equations for Barber's two self-creation theories of gravitation are solved for Friedmann-Robertson-Walker space times, using perfect fluid energy-momentum tensors. Barber's first theory is discussed for the radiation dominated case, whereas cosmologies according to Barber's second sefl-creation theory are constructed for vacuum-dominated, radiation-dominated, and dust-filled cases. 相似文献
15.
N. Riazi 《Astrophysics and Space Science》2003,283(2):235-244
Spherical, time-dependent geometrical structures in an inflationary RW background are derived from the Einstein equations,
using a constraint on the energy-momentum tensor which is an extension of the one expected for inflation. The possibility
of dynamical wormholes and other spherical structures are explored in the framework of the solutions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Walter Petry 《Astrophysics and Space Science》1992,189(1):63-77
The post-Newtonian approximation of the gravitational field of a perfect fluid for a previously stated theory of gravitation in flat space-time is studied. The conservation laws of energy-momentum and angular-momentum are derived and the equivalence of the conservation law of energy-momentum and the equations of motion is shown to the studied accuracy. The equations of motion are stated. All the results of the post-Newtonian approximation of the gravitation theory in flat space-time and of the general theory of relativity, as considered by Will in his famous book, agree to the studied accuracy. 相似文献
17.
Rabindra Nath Das 《Astrophysics and Space Science》2008,317(1-2):119-126
The linear singular integral equation derived from the nonlinear integral equation of Chandrasekhar’s H-function in radiative transfer is considered here to develop a new form of H-function as a solution of a Riemann–Hilbert problem using Plemelj and Cauchy integral formulae for complex domain. This new form of H-function is a simple integral of known functions. Forms of H-function both for conservative and nonconservative cases are obtained. Their numerical evaluations are made by Simpson’s one-third rule to arrive at an accuracy to ninth places of decimals. 相似文献
18.
In this paper, we investigate static cylindrically symmetric solution in metric f(R) gravity by taking matter in the form of dust. The assumption of constant Ricci scalar curvature is taken to find the solution.
The energy distribution of this solution is explored by applying Landau-Lifshitz energy-momentum complex. In addition, we
explore the stability as well as constant scalar curvature conditions for some viable f(R) models along with their energy distribution. It is interesting to mention here that these models satisfy the above mentioned
conditions. 相似文献
19.
R. M. Nugayev 《Astrophysics and Space Science》1983,91(1):53-62
The results of various calculations of the Casimir effect and of the effect of particle creation by accelerated mirrors are applied to the case of a collapse-formed black hole, which in consequence produces black-body radiation. Its temperature coincides exactly with Hawking's result. The difference between the vacuum expectation values of the energy-momentum tensors of scalar and electromagnetic fields near the horizon is found. Further investigation of expanding spheres in flat-space-time should disclose where the radiation is being created and what happens near the horizon. 相似文献
20.
Gamal G. L. Nashed 《Astrophysics and Space Science》2011,333(1):317-325
We derive three different solutions in the framework of the teleparallel equivalent of general relativity (TEGR). We apply
the energy-momentum tensor to calculate energy, irreducible mass, spatial momentum and angular-momentum associated with these
solutions. We obtain anomalous physical results therefore, we calculate the Killing vectors using the definition of the Lie
derivative. 相似文献