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    Öğe
    Moller energy-momentum complex in general relativity for higher dimensional universes
    (Iop Publishing Ltd, 2007) Ayguen, M.; Ayguen, S.; Yilmaz, I.; Baysal, H.; Tarhan, I.
    Using the Moller energy momentum definition in general relativity (GR) we calculate the total energy momentum distribution associated with (n + 2)-dimensional homogeneous and isotropic model of the universe. It is found that total energy of Moller is vanishing in (n + 2) dimensions everywhere but n-momentum components of Moller in (n + 2) dimensions are different from zero. Also, we evaluate the static Einstein Universe, FRW universe and de Sitter universe in four dimensions by using (n + 2)-type -metric, then calculate the Moller energy momentum distribution of these spacetimes. However, our results are consistent with the results of Banerjee and Sen, Xulu, Radinschi, Vargas, Cooperstock-Israelit, Aygun et at., Rosen, and Johri et al. in four dimensions.
  • [ X ]
    Öğe
    The Decay of Massive Scalar Field in Non-Static Godel Type Universe with Viscous Fluid and Heat Flow
    (Springer/Plenum Publishers, 2008) Ayguen, S.; Tarhan, I.
    In this study, we have investigated the dynamics of non-static Godel type rotating universe with massive scalar field, viscous fluid and heat flow in the presence of cosmological constant. For various cosmic matter forms, the behavior of the cosmological constant (Sigma), shear (eta) and bulk (xi) viscosity coefficients and other kinematic quantities have studied in the early universe. We have showed the decay of massive scalar field in the non-static rotating Godel type universe and we have obtained constant scalar field with and without source density. Also, we have investigated the effects of massive scalar field on the matter density and pressure. From solutions of the field equations, we have a cosmological model with non-zero expansion, shear, heat flux and rotation. Also some physical and geometrical aspects of the model discussed.