Searcharxiv⌕ Search

arXiv subjects

F. Rahaman

Publications and source records attributed to F. Rahaman.

68 records · Page 4Linked to original sources
arXiv2006

Lyra black holes

Long ago, since 1951, Lyra proposed a modification of Riemannian geometry. Based on the Lyra's modification on Riemannian geometry, Sen and Dunn constructed a field equation which is analogous to Einstein's field equations. Further more, Sen and Dunn gave series type solution to the static vacuum field equations. Retaining only a few terms, we have shown that their solutions correspond to black holes (we call, Lyra black holes). Some interesting properties of the Lyra black holes are studied.

gr-qc↗
arXiv2006

Wormhole with varying cosmological constant

It has been suggested that the cosmological constant is a variable dynamical quantity. A class of solution has been presented for the spherically symmetric space time describing wormholes by assuming the erstwhile cosmological constant $Λ$ to be a space variable scalar, viz., $Λ$ = $Λ(r) $ . It is shown that the Averaged Null Energy Condition (ANEC) violating exotic matter can be made arbitrarily small.

gr-qc↗
arXiv2006

Thin Shell Wormhole in Heterotic String Theory

Using 'Cut and Paste' technique, we develop a thin shell wormhole in heterotic string theory. We determine the surface stresses, which are localized in the shell, by using Darmois-Israel formalism. The linearized stability of this thin wormhole is also analyzed.

gr-qc↗
arXiv2006

Gravitational field of higher dimensional domain walls in Lyra geometry

This paper studies Thick domain wall within the framework of Lyra geometry. Their exact solutions are obtained in the background of a five dimensional space-time. The space-time is nonsingular in its both spatial and temporal behavior. The gravitational field of the wall is shown to be attractive in nature.

gr-qc↗
arXiv2006

Vacuumless cosmic strings in Einstein Cartan theory

The gravitational fields of vacuumless global and gauge strings have been investigated in the context of Einstein Cartan theory under the weak field assumption of the field equations. It has been shown that global string and gauge string can have only repulsive gravitational effect on a test particle.

gr-qc↗
arXiv2006

Thin shell wormholes in higher dimensiaonal Einstein-Maxwell theory

We construct thin shell Lorentzian wormholes in higher dimensional Einstein-Maxwell theory applying the ' Cut and Paste ' technique proposed by Visser. The linearized stability is analyzed under radial perturbations around some assumed higher dimensional spherically symmetric static solution of the Einstein field equations in presence of Electromagnetic field. We determine the total amount of exotic matter, which is concentrated at the wormhole throat.

gr-qc↗
arXiv2006

Non static local string in higher dimensional gravity

We analyze the space-time structure of local gauge string with a phenomenological energy momentum tensor, as prescribed by Vilenkin in an arbitrary number of space-time dimensions with a non-zero cosmological constant >. A set of solutions of full non-linear Einstein's equations for the interior region of such a string are presented.

gr-qc↗
arXiv2006

Local cosmic string and C-field

We investigate a local cosmic string with a phenomenological energy momentum tensor as prescribed by Vilenkin, in presence of C-field . The solutions of full nonlinear Einstein's equations for exterior and interior regions of such a string are presented.

gr-qc↗
arXiv2005

Wormhole and C-field

It is well known that a C-field, generated by a certain source equation leads to interesting changes in the cosmological solutions of Einstein's equations. In this article we present and analyze a simple Lorentzian vacuum wormhole in the presence of C-field.

gr-qc↗