Browsing by Author "Bhadra, Sumana"

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    Classical electron model with negative energy density in Einstein-Cartan theory of gravitation
    (2011-07-05) Ray, Saibal; Bhadra, Sumana
    Experimental result regarding the maximum limit of the radius of the electron ∼ 10−16 cm and a few of the theoretical works suggest that there might have some negative energy density regions within the particle in general theory of relativity. It is argued in the present investigation that such a negative energy density also can be obtained with a better physical interpretation in the framework of Einstein-Cartan theory.
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    Energy density in general relativity : a possible role of cosmological constant
    (2011-07-05) Ray, Saibal; Bhadra, Sumana
    We consider a static spherically symmetric charged anisotropic fluid source of radius ∼ 10−16 cm by introducing a variable Λ dependent on the radial coordinate r under general relativity. From the solution sets a possible role of the cosmological constant is investigated which indicates the dependency of energy density on it.
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    Relativistic anisotropic charged fluid spheres with varying cosmological constant
    (2011-07-05) Ray, Saibal; Bhadra, Sumana; Sengupta, Anand
    Static spherically symmetric anisotropic source has been studied for the Einstein- Maxwell field equations assuming the erstwhile cosmological constant Λ to be a space-variable scalar, viz., Λ = Λ(r). Two cases are examined out of which one reduces to isotropic sphere. The solutions thus obtained are shown to be electromagnetic in origin as a particular case. It is also shown that the generally used pure charge condition, viz., ρ+pr = 0 is not always required for constructing electromagnetic mass models.