Traversable wormholes with logarithmic shape function in f(R,T) gravity (original) (raw)

Traversable wormhole in logarithmic f(R) gravity by various shape and redshift functions

International Journal of Modern Physics D

In this paper, we study the traversable wormhole solutions for a logarithmic corrected [Formula: see text] model by considering two different statements of shape [Formula: see text] and redshift [Formula: see text] functions. We calculate the parameters of the model including energy density [Formula: see text], tangential pressure [Formula: see text] and radial pressure [Formula: see text] for the corresponding forms of the functions. Then, we investigate different energy conditions such as null energy condition, weak energy condition, dominant energy condition and strong energy condition for our considered cases. Finally, we explain the satisfactory conditions of energy of the models by related plots.

An Exponential Shape Function for Wormholes in Modified Gravity

Chinese Physics Letters, 2019

Here, we propose a new exponential shape function in wormhole geometry within modified gravity. The energy conditions and equation of state parameter are obtained. The radial and tangential null energy conditions are validated, as well as the weak energy condition, which indicates the absence of exotic matter due to modified gravity allied with such a new proposal.

Static Traversable Wormholes in f(R,T)=R+2αlnT Gravity

Chinese Journal of Physics

Traversable wormholes, studied by Morris and Thorne in general relativity, are investigated in this research paper in f (R, T ) gravity by introducing a new form of nonlinear f (R, T ) function. By using this novel function, the Einstein's field equations in f (R, T ) gravity are derived. To obtain the exact wormhole solutions, the relations p t = ωρ and p r = sinh(r)p t , where ρ is the energy density, p r is the radial pressure and p t is the tangential pressure, are used. Other than these relations, two forms of shape function defined in literature are used, and their suitability is examined by exploring the regions of validity of null, weak, strong and dominant energy conditions . Consequently, the radius of the throat or the spherical region, with satisfied energy conditions, is determined and the presence of exotic matter is minimized.

Traversable wormholes and energy conditions with two different shape functions in f(R) gravity

International Journal of Modern Physics D

Traversable wormholes, tunnel-like structures introduced by Morris and Thorne [Am. J. Phys. 56 (1988) 395], have a significant role in connection of two different spacetimes or two different parts of the same spacetime. The characteristics of these wormholes depend upon the redshift and shape functions which are defined in terms of radial coordinate. In literature, several shape functions are defined and wormholes are studied in [Formula: see text] gravity with respect to these shape functions [F. S. N. Lobo and M. A. Oliveira, Phys. Rev. D 80 (2009) 104012; H. Saiedi and B. N. Esfahani, Mod. Phys. Lett. A 26 (2011) 1211; S. Bahamonde, M. Jamil, P. Pavlovic and M. Sossich, Phys. Rev. D 94 (2016) 044041]. In this paper, two shape functions (i) [Formula: see text] and (ii) [Formula: see text], [Formula: see text], are considered. The first shape function is newly defined, however, the second one is collected from the literature [M. Cataldo, L. Liempi and P. Rodríguez, Eur. Phys. J. C ...

Conformally symmetric traversable wormholes in f(R,T)f(R,T)f(R,T) gravity

arXiv (Cornell University), 2019

To find more deliberate f (R, T) astrophysical solutions, we proceed by studying wormhole geometries under the assumption of spherical symmetry and the existence of a conformal Killing symmetry to attain the more acceptable astrophysical results. To do this, we consider a more plausible and simple model f (R, T) = R + 2χT , where R is the Ricci scalar and T = −ρ + pr + 2pt denotes the trace of the energy-momentum tensor of the matter content. We explore and analyze two cases separately. In the first part, wormhole solutions are constructed for the matter sources with isotropic pressure. However, the obtained solution does not satisfy the required wormhole conditions. In the second part, we introduce an EoS relating to pressure (radial and lateral) and density. We constrain the models with phantom energy EoS i.e. ω = pr/ρ < −1, consequently violating the null energy condition. Next, we analyze the model via pt = npr. Several physical properties and characteristics of these solutions are investigated which are consistent with previous references about wormholes. We mainly focus on energy conditions (NEC, WEC and SEC) and consequently for supporting the respective wormhole geometries in details. In both cases it is found that the energy density is positive as seen by any static observer. To support the theoretical results, we also plotted several figures for different parameter values of the model that helps us to confirm the predictions. Finally, the volume integral quantifier, which provides useful information about the total amount of exotic matter required to maintain a traversable wormhole is discussed briefly.

Traversable wormholes in f(R,T)$f(R,T)$ gravity

Astrophysics and Space Science

In the present article, models of traversable wormholes within the f (R, T) modified gravity theory are investigated. We have presented some wormhole models, developed from various hypothesis for the substance of their matter, i.e. various relationships with their components of pressure (lateral and radial). The solutions found for the shape functions of the wormholes produced complies with the required metric conditions. The suitability of solution is examined by exploring null, strong and dominant energy conditions. It is surmised that the normal matter in the throat may pursue the energy conditions yet the gravitational field exuding from the adjusted gravity hypothesis support the appearance of the non-standard geometries of wormholes.

Wormhole formation in massive gravity: an analytic description

The European Physical Journal C

The present study analyses the wormhole solution both in the dRGT-f(R, T) massive gravity and Einstein massive gravity. In both the models, the anisotropic pressure solution in ultrastatic wormhole geometry gives rise to the shape function that involves massive gravity parameters gamma\gammagamma γ and Lambda\LambdaLambda Λ . However, the terms consisting of gamma\gammagamma γ and Lambda\LambdaLambda Λ acts in such a way that the spacetime loses asymptotic flatness. Similar to the black hole solution in massive gravity, this inconsistency arises due to the repulsive effect of gravity which can be represented by the photon deflection angle that goes negative after a certain radial distance. It is investigated that the repulsive effect induced in the massive gravitons push the spacetime geometry so strongly that the asymptotic flatness is effected. On the other hand, in this model, one can have a wormhole with ordinary matter at the throat that satisfies all the energy conditions while the negative energ...

Wormholes in kappa(R,T)\kappa(R,T)kappa(R,T) gravity

arXiv (Cornell University), 2022

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.

Wormhole modeling in R2 gravity with linear trace term

2020

Morris and Thorne \cite{morris1} proposed traversable wormholes, hypothetical connecting tools, using the concept of Einstein's general theory of relativity. In this paper, the modification of general relativity (in particular f(R,T)f(R,T)f(R,T) theory of gravity defined by Harko et al. \cite{harko}) is considered, to study the traversable wormhole solutions. The function f(R,T)f(R,T)f(R,T) is considered as f(R,T)=R+alphaR2+betaTf(R,T)=R+\alpha R^2+\beta Tf(R,T)=R+alphaR2+betaT, where alpha\alphaalpha and beta\betabeta are controlling parameters. The shape and red shift functions appearing in the metric of wormhole structure have significant contribution in the development of wormhole solutions. We have considered both variable and constant red shift functions with a logarithmic shape function. The energy conditions are examined, geometric configuration is analyzed and the radius of the throat is determined in order to have wormhole solutions in absence of exotic matter.