17 papers found.

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Weak gravitational lensing by black holes and wormholes in the context of massive gravity (Bebronne and Tinyakov, JHEP 0904:100, 2009) theory is studied. The particular solution examined is characterized by two integration constants, the mass M and an extra parameter S namely ‘scalar charge’. These black hole reduce to the standard Schwarzschild black hole solutions when the...

A new solution satisfying the Karmarkar condition is presented here. We were first to have discovered a hypergeometric function metric potential representing embedding class I spacetime. This new solution yields finite values of metric potentials, density, pressure, redshift, etc. and hence a non-singular solution. The solution is well behaved with respect to the parameter \(n=12...

In this article, we study the possibility of sustaining static and spherically symmetric traversable wormhole geometries admitting conformal motion in Einstein gravity, which presents a more systematic approach to search a relation between matter and geometry. In wormhole physics, the presence of exotic matter is a fundamental ingredient and we show that this exotic source can be...

In the present paper we generate a set of solutions describing the interior of a compact star under \(f(R,\mathcal {T})\) theory of gravity which admits conformal motion. An extension of general relativity, the \(f(R,\mathcal {T})\) gravity is associated to Ricci scalar R and the trace of the energy-momentum tensor \(\mathcal {T}\). To handle the Einstein field equations in the...

By virtue of the maximum entropy principle, we get an Euler–Lagrange equation which is a highly nonlinear differential equation containing the mass function and its derivatives. Solving the equation by a homotopy perturbation method we derive a generalized expression for the mass which is a polynomial function of the radial distance. Using the mass function we find a partially...

Piyali Bhar
0
**Farook** **Rahaman**
0
0
Department of Mathematics, Jadavpur University
,
Kolkata 700 032, West Bengal
,
India
We propose a new model of dark energy star consisting of five zones, namely

Piyali Bhar
0
**Farook** **Rahaman**
0
0
Department of Mathematics, Jadavpur University
,
Kolkata 700 032, West Bengal
,
India
In this paper we ask whether the wormhole solutions exist in different

In this paper, we propose the braneworld gravastar configuration which is an alternative to the braneworld black hole. We study the Mazur and Mottola gravastar model within the context of the Randall–Sundrum type II braneworld scenario, based on the fact that our four dimensional spacetime is a three-brane, embedded in a five dimensional bulk. We present exact solutions of the...

We present models of wormhole under the Finslerian structure of spacetime. This is a sequel of our previous work (Eur Phys J 75:564, 2015) where we constructed a toy model for compact stars based on the Finslerian spacetime geometry. In the present investigation, a wide variety of solutions are obtained, which explore the wormhole geometry by considering different choices for the...

Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises; how could this model explain the oscillation of the universe between contraction and expansion branches? We try to address...

We provide a new class of interior solutions for anisotropic stars admitting conformal motion in higher-dimensional noncommutative spacetime. The Einstein field equations are solved by choosing a particular density distribution function of Lorentzian type as provided by Nazari and Mehdipour [1, 2] under a noncommutative geometry. Several cases with \(4\) and higher dimensions, e...

We report a \(3\)-D charged black hole solution in an anti-de Sitter space inspired by noncommutative geometry. In this construction, the black hole exhibits two horizons, which turn into a single horizon in the extreme case. We investigate the impacts of electromagnetic field on the location of the event horizon, mass and thermodynamic properties such as Hawking temperature...

We construct a toy model for compact stars based on the Finslerian structure of spacetime. By assuming a particular mass function, we find an exact solution of the Finsler–Einstein field equations with an anisotropic matter distribution. The solutions are revealed to be physically interesting and pertinent for the explanation of compact stars.

We provide a new class of exact solutions for the interior in \(2+1\) -dimensional spacetime. The solutions obtained for the perfect fluid model both with and without cosmological constant ( \(\Lambda \) ) are found to be regular and singularity free. It assumes very simple analytical forms that help us to study the various physical properties of the configuration. Solutions...

Two observational results, the density profile from simulations performed in the \(\Lambda \) CDM scenario and the observed flat galactic rotation curves, are taken as input with the aim of showing that the galactic halo possesses some of the characteristics needed to support traversable wormholes. This result should be sufficient to provide an incentive for scientists to seek...

The observed evidence for the existence of strange stars and the concomitant observed masses and radii are used to derive an interpolation formula for the mass as a function of the radial coordinate. The resulting general mass function becomes an effective model for a strange star. The analysis is based on the MIT bag model and yields the energy density, as well as the radial and...

In this article, we propose a model for a realistic strange star under Tolman VII metric (Tolman, Phys Rev 55:364, 1939). Here the field equations are reduced to a system of three algebraic equations for anisotropic pressure. Mass, central density and surface density of strange star in the low-mass X-ray binary 4U 1820-30 are matched with the observational data according to our...