This paper discusses a new wormhole solution that admits conformal motion, given a noncommutative-geometry background. After a discussion of the wormhole geometry and the energy conditions, the analysis proceeds with the calculation of the active gravitational mass, a discussion of the TOV equation describing the equilibrium conditions, as well as the nature of the total gravitational energy. The wormhole spacetime is not asymptotically flat and is therefore cut off at some radial distance and joined to an exterior vacuum solution.

In this paper we have considered the multidimensional cosmological implications of a decay law for Λ term that is proportional to βä a , where β is a constant and a is the scale factor of RW-space time. We discuss the cosmological consequences of a model for the vanishing pressure for the case k = 0. It has been observed that such models are compatible with the result of recent observations and cosmological term Λ gradually reduces as the universe expands. In this model Λ varies as the inverse square of time, which matches its natural units. The proper distance, the luminosity distance-redshift, the angular diameter distance-redshift, and look back time-redshift for the model are presented in the frame work of higher dimensional space time. The model of the Freese et al. (Nucl. Phys. B 287, 797 (1987)) for n = 2 is retrieved for the particular choice of A 0 and also Einstein-de Sitter model is obtained for A 0 = 2 3 . This work has thus generalized to higher dimensions the well-know result in four dimensional space time. It is found that there may be significant difference in principle at least, from the analogous situation in four dimensional space time.

Five-dimensional spherically symmetric spacetime is considered in bimetric theory of gravitation formulated by Rosen (Gen. Rel. Grav. 4, 435, 1973) in the presence of cosmic string dust cloud. Exact cosmological models which represent geometric (Nambu) string, p-string (Takabayasi string) and Reddy string (Astrophys. Space Sci. 301, 2006) are obtained in the static and non-static cases. Some physical properties of the models are also discussed.

We solve Einstein's field equations in higher-dimensional spherically symmetric spacetime with strange quark matter attached to the string cloud, assuming one parameter group of conformal motions. The solutions match with the higher-dimensional Reissner–Nordström metric on the boundary at r = r0. The features of the solutions are also discussed in the framework of higher-dimensional spacetime.

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