Yazar "Korunur, M." seçeneğine göre listele

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    An axially symmetric scalar field and teleparallelism
    (Springer, 2007) Korunur, M.; Salti, M.; Aydogdu, O.
    An axially symmetric scalar field is considered in teleparallel gravity. We calculate, respectively, the tensor, the vector and the axial-vector parts of torsion and energy, momentum and angular momentum in the ASSF. We find the vector parts are in the radial and (e) over cap (theta) directions, the axial-vector, momentum and angular momentum vanish identically, but the energy distribution is different from zero. The vanishing axial-vector part of torsion gives us the result that there occurs no deviation in the spherical symmetry of the spacetime. Consequently, there exists no inertia field with respect to a Dirac particle, and the spin vector of a Dirac particle becomes constant. The result for the energy is the same as obtained by Radinschi. Next, this work also (a) supports the viewpoint of Lessner that the Moller energy-momentumcomplex is a powerful concept for the energy-momentum, (b) sustains the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime, and (c) supports the hypothesis by Cooperstock that the energy is confined to the region of non-vanishing energy-momentumtens or of the matter and all non-gravitational fields.
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    Extended Ricci and holographic dark energy models in fractal cosmology
    (Springer Heidelberg, 2014) Salti, M.; Korunur, M.; Acikgoz, I.
    We consider the fractal Friedmann-Robertson-Walker universe filled with dark fluid. By making use of this assumption, we discuss two types of dark energy models: Generalized Ricci and generalized holographic dark energies. We calculate the equation-of-state parameters, investigate some special limits of the results and discuss the physical implications via graphs. Also, we reconstruct the potential and the dynamics of the quintessence and k-essence (kinetic-quintessence) according to the results obtained for the fractal dark energy.
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    Finding Dirac Spin Effect in NUT Spacetime
    (Iop Publishing Ltd, 2010) Korunur, M.; Salti, M.; Acikgoz, I.
    In the present study, we are interested in finding the spin precession of a Dirac particle in expanding and rotating NUT spacetime. A tetrad with two functions to be determined is applied to the field equation of the teleparallel theory of gravity via a coordinate transformation. The vector, the axial-vector and the tensor parts of the torsion tensor are obtained. We found that the vector parts are in the radial and phi-directions. The axial-vector torsion is along r-direction while its other components along theta and phi-directions vanish everywhere. The vector connected with Dirac spin has been evaluated as well.
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    MATTER COLLINEATIONS OF BKS-TYPE SPACETIMES
    (Editura Acad Romane, 2014) Salti, M.; Korunur, M.; Acikgoz, I.; Binbay, F.; Pirinccioglu, N.
    In the present work, we classified the BKS-type (we refer to Bianchi-Kantowski-Sachs type spacetimes collectively as the BKS-type spacetimes) spacetimes (Bianchi type-V, Bianchi type-VI (m), Bianchi type-VI:(m), Kantowski-Sachs) according to their matter collineations when the energy-momentum tensor is degenerate and also when it is non-degenerate. We find that the dimension of matter collineations is infinite and we have improper matter collineations for the degenerate case (there are seven possibilities make the energy-momentum tensor to be degenerate). Next, for the non-degenerate case of the energy-momentum tensor, we obtain proper matter collineations and find the dimension of the group is finite.