TIME-DEPENDENT WORMHOLE SOLUTIONS OF f(R) THEORY OF GRAVITY AND ENERGY CONDITIONS

Saiedi, Hamidreza; Esfahani, Bahram Nasr

doi:10.1142/s0217732311035547

Cited by 56 publications

(31 citation statements)

References 14 publications

(15 reference statements)

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“…For instance, if we take f (R) = R this condition is not satisfied and this corresponds to the need for exotic matter in Einstein's relativity. As we will show in the later part of our work, for analyzed models we typically have f R < 0 near the throat, and from (19) we obtain the condition…”

Section: Wormholes In F (R) Gravitymentioning

confidence: 65%

Wormholes in viable $$f(R)$$ f ( R ) modified theories of gravity and weak energy condition

2015

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In this work wormholes in viable f (R) gravity models are analyzed. We are interested in exact solutions for stress-energy tensor components depending on different shape and redshift functions. Several solutions of gravitational equations for different f (R) models are examined. The solutions found imply no need for exotic material, while this need is implied in the standard general theory of relativity. A simple expression for weak energy condition (WEC) violation near the throat is derived and analyzed. High curvature regime is also discussed, as well as the question of the highest possible values of the Ricci scalar for which the WEC is not violated near the throat, and corresponding functions are calculated for several models. The approach here differs from the one that has been common since no additional assumptions to simplify the equations have been made, and the functions in f (R) models are not considered to be arbitrary functions, but rather a feature of the theory that has to be evaluated on the basis of consistency with observations for the Solar System and cosmological evolution. Therefore in this work we show that the existence of wormholes without exotic matter is not only possible in simple arbitrary f (R) models, but also in models that are in accordance with empirical data.

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Section: Wormholes In F (R) Gravitymentioning

confidence: 65%

Wormholes in viable $$f(R)$$ f ( R ) modified theories of gravity and weak energy condition

2015

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“…Bronnikov et al [59] discussed the existence of wormholes in scalar tensor theory and f (R) gravity. Saiedi and Esfahani [60] studied null and weak energy conditions for wormholes with constant shape and redshift functions in f (R) gravity. Bahamonde et al [61] developed dynamical wormholes in f (R) gravity.…”

Section: Literature Surveymentioning

confidence: 99%

Traversable wormholes in $$R+\alpha R^n$$ gravity

Godani

Samanta

2020

Eur. Phys. J. C

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In this work, the study of traversable wormholes in f (R) gravity with the function f (R) = R + αR n , where α and n are arbitrary constants, is taken into account. The shape function b(r) = r exp(r−r 0 ) , proposed by Samanta et al. [71], is considered. The energy conditions with respect to both constant and variable redshift functions are discussed and the existence of wormhole solutions without presence of exotic matter is investigated.

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“…In the radiation background (T = T µ(m) µ = −ρ+p r +2p t = 0), by considering the specific shape function b(r) = r 0 and the scale factor a(t) = a 0 t n (n > 0), the following exact solution for f (R) can be achieved [22].…”

Section: Evolving Lorentzian Wormhole In F (R) Gravitymentioning

confidence: 99%

THERMODYNAMICS OF EVOLVING LORENTZIAN WORMHOLES AT APPARENT HORIZON IN f(R) THEORY OF GRAVITY

Saiedi

2012

Mod. Phys. Lett. A

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Abstract.In the context of modified f (R) gravity, we attempt to study the thermodynamic properties of the evolving Lorentzian wormholes at the apparent horizon. It is shown that the wormhole can be derived from a particular f (R) model in the radiation background. Moreover, it has been shown that the field equations can be cast to a similar form dE = T dS + W dV + T dS at the apparent horizon for the evolving Lorentzian wormhole. Compared to the case of Einstein's general relativity, an additional term T dS appears here.

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TIME-DEPENDENT WORMHOLE SOLUTIONS OF f(R) THEORY OF GRAVITY AND ENERGY CONDITIONS

Cited by 56 publications

References 14 publications

Wormholes in viable $$f(R)$$ f ( R ) modified theories of gravity and weak energy condition

Wormholes in viable $$f(R)$$ f ( R ) modified theories of gravity and weak energy condition

Traversable wormholes in $$R+\alpha R^n$$ gravity

THERMODYNAMICS OF EVOLVING LORENTZIAN WORMHOLES AT APPARENT HORIZON IN f(R) THEORY OF GRAVITY

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