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gravitational collapse with standard and dark energy in the teleparallel equivalent of general relativity

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Chinese Physics B 2012年第6期21卷 57-62页

作者： gamal g.l.nashed Mathematics Department Faculty of ScienceKing Faisal UniversityP.O.Box 380 Al-Ahsaa 31982the Kingdom of Saudi Arabia Mathematics Department Faculty of ScienceAin Shams UniversityCairo11566Egypt Center for Theoretical Physics British University of EgyptSherouk City 11837P.O.Box 43Egypt

A perfect fluid with self-similarity of the second kind is studied within the framework of the teleparallel equivalent of general relativity （TEgR）. A spacetime which is not asymptotically fiat is derived. The energy conditions of this spacetime are studied. It is shown that after some time the strong energy condition is not enough to satisfy showing a transition from standard matter to dark energy. The singularities of this solution are discussed.

关键词： perfect fluid with self-similarity of second kind teleparallel equivalent of general relativ-ity asymptotically nonflat spacetime energy conditions

Spherically symmetric solution in higher-dimensional teleparallel equivalent of general relativity

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Chinese Physics B 2013年第2期22卷 120-127页

作者： gamal g.l.nashed Center for Theoretical Physics British University in EgyptSherouk City 11837P.O.Box 43Egypt Mathematics Department Faculty of ScienceAin Shams UniversityCairo11566Egypt

A theory of（N＋1）-dimensional gravity is developed on the basis of the teleparallel equivalent of general relativity（TEgR）.The fundamental gravitational field variables are the（N＋1）-dimensional vector fields,defined globally on a manifold M,and the gravitational field is attributed to the *** form of lagrangian density is quadratic in torsion *** then give an exact five-dimensional spherically symmetric solution（Schwarzschild（4＋1）-dimensions）.Finally,we calculate energy and spatial momentum using gravitational energy-momentum tensor and superpotential 2-form.

关键词： (N+1)-dimensional teleparallel equivalent of general relativity five-dimensional solution energy and momentum

Five-dimensional teleparallel theory equivalent to general relativity,the axially symmetric solution,energy and spatial momentum

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Chinese Physics B 2011年第11期20卷 102-109页

作者： gamal g.l.nashed Mathematics Department Faculty of ScienceAin Shams University

A theory of （4＋1）-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity. The fundamental gravitational field variables are the five-dimensional vector fields （pentad）, defined globally on a manifold M, and gravity is attributed to the torsion. The lagrangian density is quadratic in the torsion tensor. We then give the exact five-dimensional solution. The solution is a generalization of the familiar Schwarzschild and Kerr solutions of the four-dimensional teleparallel equivalent of general relativity. We also use the definition of the gravitational energy to calculate the energy and the spatial momentum.

关键词： five-dimensional teleparallel equivalent of general relativity five-dimensional solution energy and spatial momentum

Nonlinear electrodynamics coupled to teleparallel theory of gravity

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Chinese Physics B 2011年第2期20卷 73-82页

作者： gamal g.l.nashed Mathematics Department Faculty of ScienceAin Shams UniversityCairoEgypt

Using nonlinear electrodynamics coupled to teleparallel theory of gravity, regular charged spherically symmetric solutions are obtained. The nonlinear theory is reduced to the Maxwell one in the weak limit and the solutions correspond to charged spacetimes. One of the obtained solutions contains an arbitrary function which we call general solution since we can generate from it the other solutions. The metric associated with these spacetimes is the same, i.e., regular charged static spherically symmetric black hole. In calculating the energy content of the general solution using the gravitational energy momentum within the framework of the teleparallel geometry, we find that the resulting form depends on the arbitrary function. Using the regularized expression of the gravitational energy-momentum we obtain the value of energy.

关键词： tetrad theory of gravitation nonlinear electrodynamics spherically symmetric black holes gravitational energy-momentum

Energy and momentum of general spherically symmetric frames on the regularizing teleparallelism

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Chinese Physics B 2012年第1期21卷 101-109页

作者： gamal g.l.nashed Centre for Theoretical Physics The British University in EgyptEl-Sherouk City 11837Egypt Mathematics Department Faculty of ScienceAin Shams University

In the context of the covariant teleparallel framework, we use the 2-form translational momentum to compute the total energy of two general spherically symmetric frames. The first one is characterized by an arbitrary function H（r）, which preserves the spherical symmetry and reproduces all the previous solutions, while the other one is characterized by a parameter ξ which ensures the vanishing of the axial of trace of the torsion. We calculate the total energy by using two procedures, i.e., when the WeitzenbSck connection Гα^β is trivial, and show how H（r） and ξ play the role of an inertia that leads the total energy to be unphysical. Therefore, we take into account Гα^β and show that although the spacetimes we use contain an arbitrary function and one parameter, they have no effect on the form of the total energy and momentum as it should be.

关键词： gravitation teleparallel gravity energy-momentum conserved currents

Energy,momentum and angular momentum in the dyadosphere of a charged spacetime in teleparallel equivalent of general relativity

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Chinese Physics B 2012年第3期21卷 85-91页

作者： gamal g.l.nashed Department of Mathematics Faculty of ScienceKing Faisal University Mathematics Department Faculty of ScienceAin Shams University Centre for Theoretical Physics The British University in Egypt

We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity （TEgR）. The definition of the gravitational energy is used to investigate the energy within the external event horizon of the dyadosphere region for the Reissner-NordstrSm black hole. We also calculate the spatial momentum and angular momentum.

关键词： Teleparallel equivalent of general relativity energy-momentum tensor angular momen- tum tensor angular momentum

Brane world black holes in teleparallel theory equivalent to general relativity and their Killing vectors,energy,momentum and angular momentum

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Chinese Physics B 2010年第2期19卷 77-91页

作者： gamal g.l.nashed Centre for Theoretical Physics The British University in EgyptEl-Sherouk CityMisr-Ismalia Desert Road Postal No.11837P.O.Box 43Egypt Mathematics Department Faculty of ScienceAin Shams UniversityCairoEgypt

The energy--momentum tensor, which is coordinate-independent, is used to calculate energy, momentum and angular momentum of two different tetrad fields. Although, the two tetrad fields reproduce the same space--time their energies are different. Therefore, a regularized expression of the gravitational energy--momentum tensor of the teleparallel equivalent of general relativity （TEgR）, is used to make the energies of the two tetrad fields equal. The definition of the gravitational energy--momentum is used to investigate the energy within the external event horizon. The components of angular momentum associated with these space--times are calculated. In spite of using a static space--time, we get a non-zero component of angular momentum! Therefore, we derive the Killing vectors associated with these space--times using the definition of the lie derivative of a second rank tensor in the framework of the TEgR to make the picture more clear.

关键词： teleparallel equivalent of general relativity brane world black holes gravitational energy--momentum tensor regularized expression of the gravitational energy--momentum

gravitational radiation fields in teleparallel equivalent of general relativity and their energies

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Chinese Physics B 2010年第11期19卷 132-139页

作者： gamal g.l.nashed Mathematics Department Faculty of ScienceAin Shams UniversityCairoEgypt Centre for Theoretical Physics The British University in EgyptEl-Sherouk CityMisr-Ismalia Desert RoadPostal No.11837Egypt

We derive two new retarded solutions in the teleparallel theory equivalent to general relativity （TEgR）. One of these solutions gives a divergent energy. Therefore, we use the regularized expression of the gravitational energymomentum tensor, which is a coordinate dependent. A detailed analysis of the loss of the mass of Bondi space-time is carried out using the flux of the gravitational energy-momentum.

关键词： teleparallel equivalent of general relativity energy-momentum tensor Bondi mass gravitational radiation

Teleparallel equivalent theory of (1+1)-dimensional gravity

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Chinese Physics B 2010年第11期19卷 124-131页

作者： gamal g.l.nashed Mathematics Department Faculty of ScienceAin Shams UniversityCairoEgypt Centre for Theoretical Physics The Bvitish University in EgyptEl-Sherouk CityMisr-Ismalia Desert RoadPostal No.11837P.O.Box 43Egypt

A theory of （1＋1）-dimensional gravity is constructed on the basis of the teleparallel equivalent of general relativity. The fundamental field variables are the tetrad fields ei^μ and the gravity is attributed to the torsion. A dilatonic spherically symmetric exact solution of the gravitational field equations characterized by two parameters M and Q is derived. The energy associated with this solution is calculated using the two-dimensional gravitational energy- momentum formula.

关键词： teleparallel equivalent theory of (1+1)-dimensional gravity two-dimensional spherically symmetric dilatonic black hole energy