Wormhole in the modified theory of gravity in Kaluza–Klein cosmology

Sarkar, Kaushik; Biswas, Gargi; Modak, B.

doi:10.1007/s10714-018-2480-3

Cited by 7 publications

(4 citation statements)

References 44 publications

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“…Sharif and Ikram [27] have studied the traversable WH solutions in the framework of f (G) gravity (where G is the Gauss-Bonnet curvature invariant) and found that the effective stress-energy tensor violates the NEC throughout the WH throat. Sarkar et al [28] have discussed WH in a modified theory of gravity in the background five dimensional Kaluza-Klein cosmology. Samanta et al [29] have presented a comparative study of traversable WHs with exponential shape function in f (R) and f (R, T ) modified gravities and in general relativity.…”

Section: Introductionmentioning

confidence: 99%

Wormholes in $κ(R,T)$ gravity

Sarkar¹,

Sarkar²,

Rahaman³

et al. 2022

Preprint

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The wormhole solution could be found by solving the Einstein field equations with violating the null energy condition (NEC). We represent wormhole solutions in κ(R, T ) gravity in two different ways. At first, we find the shape function by considering a redshift function and linear equation of state (EoS). The solution represents a wormhole for the real feasible matter. In the second part, we consider four pairs of two redshift functions and two shape functions and analyze the obtained solutions. Some of the models suggest that for particular values of the parameters, the existence of wormholes are supported by an arbitrarily small quantity of exotic matter.

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Section: Introductionmentioning

confidence: 99%

Wormholes in $κ(R,T)$ gravity

Sarkar¹,

Sarkar²,

Rahaman³

et al. 2022

Preprint

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“…Further, the solutions for the "00"-component of R µν = 3λg µν are relevant to our solutions both for positive and negative values of λ, but the "space-space" components of the equations of class (ii) do not belong to our class of solutions. Interestingly, power law inflation [48] is obtained asymptotically from an Euclidean wormhole in gravity with R 3 2 term using Noether symmetry. In a recent work [49] it is shown that an Euclidean wormhole in the early universe evolved to an inflationary era away from the throat of the wormhole using τ = it in 5-dimensional Kaluza Klein spacetime minimally coupled with a scalar field.…”

Section: Introductionmentioning

confidence: 99%

Wormhole inducing exponential expansion in $R^2$ gravity

Modak¹,

Biswas²

2021

Preprint

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We present a few exact solutions of the Euclidean field equations in R 2 gravity in spatial homogeneous and isotropic background in 4-dimension. Wormhole configuration, as well as oscillatory scale factors are obtained as a function of Euclidean time τ for κ = 0, ±1. Each of the oscillatory solution in τ reduces to the Lorentzian wormhole using analytic continuation from Euclidean space to Lorentz spacetime by τ = it. The Lorentzian wormhole leads to an exponential expanding era asymptotically. An Euclidean wormhole in the very early universe could evolve to an inflationary era at later epoch for κ = 1.

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“…Inflationary cosmology [1][2][3][4] resolves most of the problems of standard cosmology, except cosmic singularity and vanishing of cosmological constant [5]. To avoid cosmic singularity in the early universe several gravitational theories, like modified theories of gravity [6][7][8][9], string theory [10,11], Kaluza-Klein gravity [12,13], etc appear as natural generalization of Einstein's gravity. The Einstein Gauss Bonnet dilatonic (referred as DEGB) coupled interaction arises logically as the leading order in the low energy effective Heterotic string theory [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…In continuation several wormhole solutions [24][25][26][27][28][29] have been explored with different fields, as well as to study consequences of wormhole dynamics [20], [30][31][32][33][34][35][36]. The wormhole solution demands violation of null energy condition (ρ ef f + p ef f ) ≥ 0 (NEC) [37], whose effect can be minimised by invoking some geometric contribution instead of exotic fields in the alternative theories of gravity [7][8][9][10][11][12][13]. The effective density and effective pressure are respectively ρ ef f and p ef f .…”

Section: Introductionmentioning

confidence: 99%

Wormhole inducing inflation with Einstein Gauss Bonnet dilaton interaction

Biswas,

Dutta,

Modak

2021

Preprint

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We present a few Euclidean wormhole configurations using both the analytic and numerical solutions of the field equations considering Einstein Gauss-Bonnet dilaton interaction in 4-dimensional Robertson Walker Euclidean background. The analytic solutions in some cases show a transition to an exponential expansion with Lorentzian time t using τ = it after passing through an era of oscillating Euclidean wormhole. The numerical solutions of the scale factor a(τ ) show multiple local maxima and minima about a global minimum for inverse power law potentials, while for exponential potential the wormholes have a single minimum. The Hubble parameter and deceleration parameter obtained by curve fit of a(τ ) of the numerical solution show an inflation away from the throat of the wormhole invoking analytic continuation by τ = it. A sharp decay of the potential is also observed.

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Wormhole in the modified theory of gravity in Kaluza–Klein cosmology

Cited by 7 publications

References 44 publications

Wormholes in $κ(R,T)$ gravity

Wormholes in $κ(R,T)$ gravity

Wormhole inducing exponential expansion in $R^2$ gravity

Wormhole inducing inflation with Einstein Gauss Bonnet dilaton interaction

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