Wormholes supported by Scalar Fields with Negative Kinetic Energy (2008)
Rahaman, F., Kalam, M., Rahman, K. A.
We provide a new model of higher dimensional wormholes supported by phantom energy derived from a scalar field with negative kinetic term. We have shown that the Averaged Null Energy Condition (ANEC)...
Chaplygin electron gas model (2008)
Radinschi, I., Rahaman, F., Kalam, M., Chakraborty, K.
We provide a new electromagnetic mass model admitting Chaplygin gas equation of state. We investigate three specializations, the first characterized by a vanishing effective pressure, the second...
Discussion on some characteristics of the Charged Brane-world Black holes (2008)
Kalam, M., Rahaman, F., Ghosh, A., Raychaudhuri, B.
Several physical natures of charged brane-world black holes have been investigated. At first, time-like and null geodesics of the charged brane-world black holes are presented. We also analyze all...
Rahaman, F., Kalam, M., Chakraborty, S., Maity, K., Raychaudhuri, B.
In this article, a special static spherically symmetric perfect fluid solution of Einstein's equations is provided. Though pressure and density both diverge at the origin, their ratio remains...
Wormhole geometry from real feasible matter sources (2008)
Rahaman, F., Kalam, M., Rahman, K. A.
We provide a prescription of real feasible sources that supply fuel to construct a traversable wormhole. A class of exact solutions for Einstein-Maxwell field equations describing wormhole with an...
Electromagnetic mass model admitting conformal motion (2008)
Ray, Saibal, Usmani, A A, Rahaman, F, Kalam, M, Chakraborty, K
We study charged fluid spheres under the 4-dimensional Einstein-Maxwell space-time. The solutions thus obtained admitting conformal motion. We also investigate whether the solutions set provide...
Thin shell wormhole due to dyadosphere of a charged black hole (2008)
Rahaman, F., Kalam, M., Rahman, K A
To explain Gamma Ray Bursts, Ruffini argued that the event horizon of a charged black hole is surrounded by a special region called, the Dyadosphere where electric field exceeds the critical value...
Motion of Massive and Massless Test particles in Dyadosphere Geometry (2008)
Raychaudhuri, B., Rahaman, F., Kalam, M., Ghosh, A.
Motion of massive and massless test particle in equilibrium and non-equilibrium case is discussed in a dyadosphere geometry through Hamilton-Jacobi method. Geodesics of particles are discussed...
Rahaman, F., Kalam, M., Rahman, K. A.
It is well known that solutions of general relativity which allow for traversable wormholes require the existence of exotic matter (matter that violates weak or null energy conditions [WEC or NEC])....
Conical thin shell wormhole from global monopole: A theoretical construction (2008)
Rahaman, F., Kalam, M., Rahman, K. A.
By applying 'Darmois-Israel formalism', we establish a new class of thin shell wormhole in the context of global monopole resulting from the breaking of a global O(3) symmetry. Since global monopole...
Galactic rotation curves and brane world models (2008)
Rahaman, F., Kalam, M., DeBenedictis, A., Usmani, A. A., Ray, Saibal
In the present investigation flat rotational curves of the galaxies are considered under the framework of brane-world models where the 4d effective Einstein equation has extra terms which arise from...
Some new class of Chaplygin Wormholes (2007)
Rahaman, F., Kalam, M., Rahman, K. A.
Some new class of Chaplygin wormholes are investigated in the framework of a Chaplygin gas with equation of state $ p = - \frac{A}{\rho}$, $A>0$. Since empty spacetime ($ p = \rho = 0 $) does not...
Wormhole and C-field: Revisited (2007)
Rahaman, F., Sarker, M., Kalam, M.
Recently, Rahaman et al [ Nuovo.Cim 119B, 1115(2004)] have shown that the static spherically symmetric solutions in presence of C-field give rise to wormhole geometry. We highlight some of the...
Do Solar system tests permit higher dimensional general relativity? (2007)
Rahaman, F., Ray, Saibal, Kalam, M., Sarker, M.
We perform a survey whether higher dimensional Schwarzschild space-time is compatible with some of the solar system phenomena. As a test we examine five well known solar system effects, viz., (1)...
Particle Motion Around Tachyon Monopole (2007)
Kalam, M., Rahaman, F., Mondal, S.
Recently, Li and Liu have studied global monoole of tachyon in a four dimensional static space-time. We analyze the motion of massless and massive particles around tachyon monopole. Interestingly,...
Construction of 3D wormhole supported by phantom energy (2007)
Rahaman, F., Kalam, M., Bhui, B. C., Chakraborty, S.
In this article, we have found a series solution of 3D Einstein equations describing a wormhole for an inhomogeneous distribution of phantom energy. Here, we assume equation of state is linear but...
Gravitational lensing by stable C-field wormhole (2007)
Rahaman, F., Kalam, M., Chakraborty, S.
It has been recently shown that Hoyle-Narlikar's C-field theory admits wormhole geometry. We derive the deflection angle of light rays caused by C-field wormhole in the strong field limit approach of...
A Theoretical Construction of Thin Shell Wormhole from Tidal Charged Black hole (2007)
Rahaman, F., Kalam, M., Rahman, K A, Chakraborti, S.
Recently, Dadhich et al [ Phys.Lett.B 487, 1 (2000)] have discovered a black hole solution localized on a three brane in five dimensional gravity in the Randall-Sundrum scenario. In this article, we...
Vacuum less global monopole in Brans-Dicke theory (2007)
Rahaman, F., Kalam, M., Mukherjee, R., Das, S., Roy, T.
In the present work, the gravitational field of a vacuum less global monopole has been investigated in Brans-Dicke theory under weak field assumption of the field equations. It has been shown that...
Wormholes with varying equation of state parameter (2007)
Rahaman, F., Kalam, M., Chakraborty, S.
We propose wormholes solutions by assuming space dependent equation of state parameter. Our models show that the existence of wormholes is supported by arbitrary small quantities of averaged null...
Does phantom energy produce black hole? (2006)
Rahaman, F., Ghosh, A., Kalam, M.
We have found an exact solution of spherically symmetrical Einstein equations describing a black hole with a special type phantom energy source. It is surprising to note that our solution is...
Bianchi -I Cosmology with Magnetic Field in Lyra Geometry (2006)
Rahaman, F., Begum, N., Das, S., Hossain, M., Kalam, M.
A new class of Bianchi - I cosmological model with magnetic field within the frame work of Lyra geometry has been presented . Exact solutions to the field equations for the model are obtained . The...
Rahaman, F., Ghosh, A., Kalam, M.
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...
Wormhole with varying cosmological constant (2006)
Rahaman, F., Kalam, M., Sarker, M., Ghosh, A., Raychaudhuri, B.
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...
Thin Shell Wormhole in Heterotic String Theory (2006)
Rahaman, F., Kalam, M., Chakraborti, S.
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....
Global monopole, dark matter and scalar tensor theory (2006)
Rahaman, F., Kalam, M., Mondal, R., Raychaudhuri, B.
In this article, we discuss the space-time of a global monopole field as a candidate for galactic dark matter in the context of scalar tensor theory.
Thin shell wormholes in higher dimensiaonal Einstein-Maxwell theory (2006)
Rahaman, F., Kalam, M., Chakraborty, S.
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...
Existence of Wormholes in Einstein-Kalb-Ramond space time (2006)
Rahaman, F., Kalam, M., Ghosh, A.
In recent, Kar.S et.al [ Phys Rev D 67,044005 (2003) ] have obtained static spherically symmetric solutions of the Einstein-Kalb-Ramond field equations. We have shown that their solutions, indeed,...
Thin Domain Walls in Lyra Geometry (2006)
Rahaman, F., Kalam, M., Mondal, R.
This paper studies thin domain walls within the frame work of Lyra Geometry. We have considered two models. First one is the thin domain wall with negligible pressures perpendicular and transverse...
Non static local string in higher dimensional gravity (2006)
Rahaman, F., Bhui, B. C., Kalam, M.
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...
Higher dimensional global monopole with cosmological term (2006)
Rahaman, F., Ghosh, P., Kalam, M., Gayen, K.
We investigate the space-time of a global monopole in a five dimensional space-time in presence of the cosmological term. Also the gravitational properties of the monopole solution are discussed.
Local cosmic string and C-field (2006)
Rahaman, F., Mondal, R., Kalam, M.
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...
Multidimensional global monopole in presence of Electromagnetic Field (2005)
Rahaman, F., Ghosh, P., Kalam, M., Mandal, S.
We study the gravitational properties of a global monopole in $(D = d + 2)$ dimensional space-time in presence of electromagnetic field.
A theoretical construction of wormhole supported by Phantom Energy (2005)
Rahaman, F., Kalam, M., Sarker, M., Gayen, K.
A new solution has been presented for the spherically symmetric space time describing wormholes with Phantom Energy. The model suggests that the existence of wormhole is supported by arbitrarily...