Study of galactic halo F(T,TG) wormhole solutions

2017 ◽  
Vol 27 (01) ◽  
pp. 1750170
Author(s):  
M. Sharif ◽  
Kanwal Nazir
Keyword(s):  
Equilibrium Condition ◽  
Galactic Halo ◽  
Shape Function ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Wormhole Solution ◽  
Torsion Scalar ◽  
Specific Formula ◽  
Bonnet Term

In this paper, we investigate static spherically symmetric wormhole solutions with galactic halo region in the background of [Formula: see text] gravity. Here, [Formula: see text] represents torsion scalar and [Formula: see text] is teleparallel equivalent Gauss–Bonnet term. For this purpose, we consider a diagonal tetrad and two specific [Formula: see text] models. We analyze the wormhole structure through shape function graphically for both models. We also investigate the behavior of null/weak energy conditions. Finally, we evaluate the equilibrium condition to check stability of the wormhole solutions. It is concluded that there exists physically viable wormhole solution only for the first model that turns out to be stable.

scholarly journals Lorentz Distributed Noncommutative F(T,TG) Wormhole Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
M. Sharif ◽  
Kanwal Nazir
Keyword(s):  
Equilibrium Condition ◽  
Shape Function ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Torsion Scalar ◽  
Lorentzian Distribution ◽  
The Stability ◽  
Bonnet Term

The aim of this paper is to study static spherically symmetric noncommutative F(T,TG) wormhole solutions along with Lorentzian distribution. Here, T and TG are torsion scalar and teleparallel equivalent Gauss-Bonnet term, respectively. We take a particular redshift function and two F(T,TG) models. We analyze the behavior of shape function and also examine null as well as weak energy conditions graphically. It is concluded that there exist realistic wormhole solutions for both models. We also studied the stability of these wormhole solutions through equilibrium condition and found them stable.

scholarly journals Noncommutative Wormhole Solutions in Einstein Gauss-Bonnet Gravity

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Shamaila Rani ◽  
Abdul Jawad
Keyword(s):  
Noncommutative Geometry ◽  
Equilibrium Condition ◽  
Shape Function ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Bonnet Gravity

We explore static spherically symmetric wormhole solutions in the framework ofn-dimensional Einstein Gauss-Bonnet gravity. Our objective is to find out wormhole solutions that satisfy energy conditions. For this purpose, we consider two frameworks such as Gaussian distributed and Lorentzian distributed noncommutative geometry. Taking into account constant redshift function, we obtain solutions in the form of shape function. The fifth and sixth dimensional solutions with positive as well as negative Gauss-Bonnet coefficient are discussed. Also, we check the equilibrium condition for the wormhole solutions with the help of generalized Tolman-Oppenheimer-Volkoff equation. It is interesting to mention here that we obtain fifth dimensional stable wormhole solutions in both distributions that satisfy the energy conditions.

scholarly journals Wormholes in 4D Einstein–Gauss–Bonnet gravity

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Kimet Jusufi ◽  
Ayan Banerjee ◽  
Sushant G. Ghosh
Keyword(s):  
Symmetric Solution ◽  
Shape Function ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Coupling Constant ◽  
Volume Integral ◽  
Wormhole Solution ◽  
Anisotropic Matter ◽  
Spherically Symmetric Solution ◽  
Significant Interest

Abstract Recent times witnessed a significant interest in regularizing, a $$ D \rightarrow 4 $$D→4 limit, of EGB gravity initiated by Glavan and Lin [Phys. Rev. Lett. 124, 081301 (2020)] by re-scaling GB coupling constant as $$\alpha /(D-4)$$α/(D-4) and taking limit $$D \rightarrow 4$$D→4, and in turn these regularized 4D gravities have nontrivial gravitational dynamics. Interestingly, the maximally or spherically symmetric solution to all the regularized gravities coincides in the 4D case. In view of this, we obtain an exact spherically symmetric wormhole solution in the 4D EGB gravity for an isotropic and anisotropic matter sources. In this regard, we consider also a wormhole with a specific radial-dependent shape function, a power-law density profile as well as by imposing a particular equation of state. To this end, we analyze the flare-out conditions, embedding diagrams, energy conditions and the volume integral quantifier. In particular our −ve branch results, in the limit $$\alpha \rightarrow 0$$α→0, reduced exactly to vis-$$\grave{a}$$a`-vis 4D Morris-Thorne of GR.

Noncommutative wormhole solutions in f(G) gravity

2015 ◽  
Vol 30 (28) ◽  
pp. 1550142 ◽  
Author(s):  
M. Sharif ◽  
H. Ismat Fatima
Keyword(s):  
Shape Function ◽  
Energy Conditions ◽  
Radial Coordinate ◽  
Spherically Symmetric ◽  
Wormhole Solution ◽  
Physical Solution ◽  
Bonnet Gravity ◽  
First Case ◽  
Normal Matter ◽  
Text Model

In this paper, we study noncommutative static spherically symmetric wormhole solutions in the context of modified Gauss–Bonnet gravity. We explore these solutions either by assuming a viable [Formula: see text] model to construct shape function or by specifying the shape function to deduce [Formula: see text] model. The energy conditions are discussed for both types of wormholes. In the first case, we find a physically acceptable wormhole solution threaded by normal matter for all values of radial coordinate [Formula: see text] while the second case gives physical solution only for large values of [Formula: see text].

Noncommutative wormhole solutions in F(T, T𝒢) gravity

2017 ◽  
Vol 32 (13) ◽  
pp. 1750083 ◽  
Author(s):  
M. Sharif ◽  
Kanwal Nazir
Keyword(s):  
Noncommutative Geometry ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Wormhole Solution

This paper is devoted to the study of static spherically symmetric wormhole solutions along with noncommutative geometry in the background of F(T, T[Formula: see text]) gravity. We assume a nonzero redshift function as well as two well-known models of this gravity and discuss the behavior of null/weak energy conditions graphically. We conclude that there does not exist any physically acceptable wormhole solution for the first model, but there is a chance to develop physically acceptable wormhole solution in a particular region for the second model.

scholarly journals Some specific wormhole solutions in f(R)-modified gravity theory

2021 ◽  
pp. 2150024
Author(s):  
Bikram Ghosh ◽  
Saugata Mitra ◽  
Subenoy Chakraborty
Keyword(s):  
Modified Gravity ◽  
Shape Function ◽  
Matter Field ◽  
Gravity Theory ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Shape Functions ◽  
Matter Distribution ◽  
Anisotropic Matter ◽  
Modified Gravity Theory

The paper deals with the static spherically symmetric wormhole solutions in [Formula: see text]-modified gravity theory with anisotropic matter field and for some particular choices for the shape functions. This work may be considered as an extension of the general formalism in [S. Halder, S. Bhattacharya and S. Chakraborty, Phys. Lett. B 791, 270 (2019)] for finding wormhole solutions. For isotropic matter distribution it has been shown that wormhole solutions are possible for zero tidal force and it modifies the claim in [M. Cataldo, L. Leimpi and P. Rodriguez, Phys. Lett. B 757, 130 (2016)]. Finally, energy conditions are examined and it is found that all energy conditions are satisfied in a particular domain with a particular choice of the shape function.

scholarly journals Stable Wormholes in the Background of an Exponential f(R) Gravity

Universe ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 48 ◽  
Author(s):  
Ghulam Mustafa ◽  
Ibrar Hussain ◽  
M. Farasat Shamir
Keyword(s):  
Stability Analysis ◽  
Equation Of State ◽  
Shape Function ◽  
Energy Condition ◽  
Energy Conditions ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Shape Functions ◽  
Spacetime Geometry ◽  
Specific Shape

The current paper is devoted to investigating wormhole solutions with an exponential gravity model in the background of f ( R ) theory. Spherically symmetric static spacetime geometry is chosen to explore wormhole solutions with anisotropic fluid source. The behavior of the traceless matter is studied by employing a particular equation of state to describe the important properties of the shape-function of the wormhole geometry. Furthermore, the energy conditions and stability analysis are done for two specific shape-functions. It is seen that the energy condition are to be violated for both of the shape-functions chosen here. It is concluded that our results are stable and realistic.

Spherically symmetric static wormhole models in the Einsteinian cubic gravity

2020 ◽  
Vol 17 (14) ◽  
pp. 2050214
Author(s):  
G. Mustafa ◽  
Tie-Cheng Xia ◽  
Ibrar Hussain ◽  
M. Farasat Shamir
Keyword(s):  
Shape Function ◽  
Necessary Conditions ◽  
General Relation ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Shape Functions ◽  
Anisotropic Matter ◽  
Lorentzian Signature ◽  
Fields Equations

Our aim is to discuss spherically symmetric static wormholes with the Lorentzian signature in the Einsteinian cubic gravity for two different models of pressure sources. First, we calculate the modified fields equations for the Einsteinian cubic gravity for the wormhole geometry under the anisotropic matter. Then we investigate the shape-function for two different models, which can be taken as a part of the general relation, namely, [Formula: see text]. We further study the energy conditions for both the models in the background of the Einsteinian cubic gravity. We show that our obtained shape-functions satisfy all the necessary conditions for the existence of wormhole solutions in the Einsteinian cubic gravity for some particular values of the different involved parameters. We also discuss the behavior of the energy conditions especially the null and the weak energy conditions for the wormhole models in the Einsteinian cubic gravity.

scholarly journals Collapsing Wormholes Sustained by Dustlike Matter

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 186
Author(s):  
Pavel E. Kashargin ◽  
Sergey V. Sushkov
Keyword(s):  
General Relativity ◽  
General Solution ◽  
Space Time ◽  
Time Structure ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Friedmann Universe ◽  
Dust Shell ◽  
Wormhole Solution ◽  
Space Time Structure

It is well known that static wormhole configurations in general relativity (GR) are possible only if matter threading the wormhole throat is “exotic”—i.e., violates a number of energy conditions. For this reason, it is impossible to construct static wormholes supported only by dust-like matter which satisfies all usual energy conditions. However, this is not the case for non-static configurations. In 1934, Tolman found a general solution describing the evolution of a spherical dust shell in GR. In this particular case, Tolman’s solution describes the collapsing dust ball; the inner space-time structure of the ball corresponds to the Friedmann universe filled by a dust. In the present work we use the general Tolman’s solution in order to construct a dynamic spherically symmetric wormhole solution in GR with dust-like matter. The solution constructed represents the collapsing dust ball with the inner wormhole space-time structure. It is worth noting that, with the dust-like matter, the ball is made of satisfies the usual energy conditions and cannot prevent the collapse. We discuss in detail the properties of the collapsing dust wormhole.

Galactic halo traversable wormhole solutions in f(𝒢,T) gravity

2018 ◽  
Vol 27 (16) ◽  
pp. 1950009 ◽  
Author(s):  
M. Sharif ◽  
Ayesha Ikram
Keyword(s):  
Galactic Halo ◽  
Shape Function ◽  
Energy Momentum Tensor ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Momentum Tensor ◽  
Specific Form ◽  
Spherically Symmetric ◽  
Effective Energy ◽  
Text Model

This paper explores static spherically symmetric wormhole solutions in the galatic halo region for [Formula: see text] gravity ([Formula: see text] and [Formula: see text] represent the Gauss–Bonnet invariant and trace of the energy–momentum tensor, respectively). We formulate the explicit expressions for matter variables and evaluate wormhole solutions either specifying [Formula: see text] model to construct shape function or taking specific form of the shape function to determine [Formula: see text] model. It is found that null energy condition for the effective energy–momentum tensor is violated throughout the evolution in both cases while physically acceptable wormhole solutions exist only for a considered [Formula: see text] model.

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