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By
Patel, L K; Koppar, S S; Singh, Tajinder
Three exact nonstatic solutions of EinsteinMaxwell equations corresponding to a field of flowing null radiation plus an electromagnetic field are presented. These solutions are nonstatic generalizations of the well known KerrNewman solution. The current vector is null in all the three solutions. These solutions are the electromagnetic generalizations of the three generalized radiating Kerr solutions discussed by Vaidya and Patel. The solutions discussed by us describe the exterior gravitational fields of rotating radiating charged bodies. Many known solutions are derived as particular cases.
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By
Johri, V B; Singh, G P
The behaviour of gravitational energy and scalar field during the evolution of the universe within the framework of BransDicke theory has been discussed. With help of the LandauLifshitz pseudotensor for the flat FriedmannRobertsonWalker model, it is found that (i) the total energy of the universe is always zero, (ii) the BransDicke scalar field for all Ω >0 contributes energy to the negative energy of gravitational field and this gets transferred to the vacuum energy which accelerates the expansion of the universe.
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By
González, Guillermo; LópezBonilla, José L; Rosales, Marco A
1 Citations
An identity is obtained for a Riemanniannspace (R_{n}) locally and isometrically embedded into a pseudoEuclidean (n+1)space (E_{n+1}), relating the corresponding second fundamental form with the intrinsic geometry ofR_{n}. Forn=4 such an identity reduces to a previous result by Goenner.
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By
Chakraborty, Subenoy
Classical and quantum cosmological aspects for (n + 2) dimensional anisotropic spherically symmetric spacetime with topology of (n + 1) spaceS^{1}×S^{n} have been studied. The Lorentzian field equations are reduced to an autonomous system by a change of field variables and are discussed near the critical points. The path integral expression for propagation amplitude is converted to a single ordinary integration over the lapse function by the usual technique and is evaluated in terms of Bessel functions.
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By
Vaidya, P. C.; Patel, L. K.
A method of obtaining solutions of Einstein field equations, representing rotating type II null fluids is presented. One explicit solution is given and its details are discussed. The wellknown deSitter metric is derived as a particular case.
By
Chakraborty, Subenoy; Shah, Md. Firoj
We study spherically symmetric inhomogeneous cosmological model with heat flow in higher dimensional spacetime and present a class of solutions in which the velocity field is shearfree. Some of these solutions are analogous to the known solutions in 4dimension while some are totally new.
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By
Sitaram, B R; Varma, Ram K
We consider here the problem of the existence of a quasiinvariant which is linear in the momenta for Hamiltonians in three degrees of freedom. We show that such quasiinvariants are more constrained in their structure than in the two degrees of freedom case. We also show that some of these quasiinvariants have to be interpreted as ‘pseudotranslations’, i.e., as translations in a nonorthogonal system of coordinates.
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By
Tikekar, Ramesh; Thomas, V. O.
25 Citations
An exact solution of Einstein’s field equations for anisotropic fluid distribution on the background of a pseudospheroidal spacetime has been reported. The models based on this solution are found to accommodate density variation of high degree from the centre to the boundary of the distribution and admit a subclass for which both the radial and tangential pressures vanish at the boundary of the configuration.
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By
Vaidya, P C; Patel, L K
11 Citations
Spatially homogeneous spacetimes of Bianchi type IX are considered. A general scheme for the derivation of exact solutions of Einstein’s equations corresponding to perfect fluid plus pure radiation fields is outlined. Some simple rotating Bianchi type IX cosmological models are presented. The details of these solutions are also discussed.
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By
LópezBonilla, José L; NúñezYépez, H N
We show that if a 4spacetimeV_{4} can be embedded intoE_{5} then, ifb_{ij}is the second fundamental form tensor associated withV_{4}, the quantity (traceb)·b_{ij}^{/−1}
depends only on intrinsic geometric properties of the spacetime. Such fact is used to obtain a necessary condition for the embedding of aV_{4} intoE_{5}.
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