An Exponential Shape Function for Wormholes in Modified Gravity*

Moraes, P. H. R. S.; Sahoo, P. K.; Kulkarni, Shreyas Sunil; Agarwal, Shivaank

doi:10.1088/0256-307x/36/12/120401

Cited by 23 publications

(8 citation statements)

References 83 publications

(74 reference statements)

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“…Here m 1 , m 2 and m 3 are the model parameters and r 0 denotes the throat radius of the wormholes. The first toy model has been widely used in different works [120][121][122]. Whereas other two toy functions have been introduced by us as two possible shapes or structures of wormhole.…”

Section: Toy Models Of Wormhole Shape Functionmentioning

confidence: 99%

Tideless traversable wormholes surrounded by cloud of strings in f(R) gravity

Gogoi

Goswami

2023

J. Cosmol. Astropart. Phys.

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We study the tideless traversable wormholes in the f(R) gravity metric formalism. First we consider three shape functions of wormholes and study their viabilities and structures. The connection between the f(R) gravity model and wormhole shape function has been studied and the dependency of the f(R) gravity model with the shape function is shown. We also obtain a wormhole solution in the f(R) gravity Starobinsky model surrounded by a cloud of strings. In this case, the wormhole shape function depends on both the Starobinsky model parameter and the cloud of strings parameter. The structure and height of the wormhole is highly affected by the cloud of strings parameter, while it is less sensitive to the Starobinsky model parameter. The energy conditions have been studied and we found the ranges of the null energy condition violation for all wormhole structures. The quasinormal modes from these wormhole structures for the scalar and Dirac perturbations are studied using higher order WKB approximation methods. The quasinormal modes for the toy shape functions depend highly on the model parameters. In case of the Starobinsky model's wormhole the quasinormal frequencies and the damping rate increase with an increase in the Starobinsky model parameter in scalar perturbation. Whereas in Dirac perturbation, with an increase in the Starobinsky model parameter the quasinormal frequencies decrease and the damping rate increases. The cloud of strings parameter also impacts prominently and differently the quasinormal modes from the wormhole in the Starobinsky model.

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Section: Toy Models Of Wormhole Shape Functionmentioning

confidence: 99%

Tideless traversable wormholes surrounded by cloud of strings in f(R) gravity

Gogoi

Goswami

2023

J. Cosmol. Astropart. Phys.

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“…The first shape function was presented in the seminal work of Lobo et al [28], where it was verified the viability of wormhole solutions for different f (R) gravity theories. The second shape function was introduced by Moraes et al [29], in order to fulfill the energy conditions constraints for wormholes in f (R, T) gravity theories. Moreover, these shape functions satisfies all the basic criteria of traversable wormhole.…”

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confidence: 99%

Embedding procedure and wormhole solutions in f(Q) gravity

Hassan¹,

Mustafa²,

Santos³

et al. 2022

EPL

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An intriguing solution that appears in General Relativity (GR) but has not been observed so far is the wormhole. This exotic solution describes a topological bridge connecting two distinct universes or two different points in the same universe. It is known that the traversable wormhole solutions violate all the energy conditions in GR, resulting in their instability. In this work, we are going to unveil new wormhole solutions for $f(Q)$ gravity where $Q$ is the non-metricity scalar, which is responsible for the gravitational interaction. The energy conditions to constraint these wormhole solutions were derived using the embedding procedure. This procedure consists of rewriting the density and the pressures of the solutions as those presented by General Relativity. Then, the nontrivial contributions coming from new theories of gravity are embedded into the effective equations for density and pressures. Along with our approach, we carefully analyze two families of $f(Q)$ models and we used two different shape functions to build the wormholes solutions for each of these $f(Q)$ models. We are going to present new scenarios with the possibility of traversable wormholes satisfying SEC or DEC energy conditions in the presence of exotic matter.

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“…We also assume that the wormhole is tidal with the redshift function (for more details, see Moraes et al 2019;Anchordoqui et al 1998 and references therein)…”

Section: Schwarzschild-like Wormholementioning

confidence: 99%

Accretion flows around exotic tidal wormholes

Sokoliuk

Praharaj

Baransky

et al. 2022

A&A

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Aims. This paper investigates the various spherically symmetric wormhole solutions in the presence of tidal forces and applies numerous methods, such as test particle orbital dynamics, ray-tracing, and microlensing. Methods. We make theoretical predictions on the test particle orbital motion around the tidal wormholes with the use of the effective potential normalized by L 2 . In order to obtain the ray-tracing images of both geometrically thin and thick accretion disks and relativistic jets, we modified the open source GYOTO code using a python interface Results. We applied this technique to probe the accretion flows near Schwarzschild-like and charged Reissner-Nordström (RN) wormholes; we assumed both a charged RN wormhole and a special case with a vanishing electromagnetic charge, namely the Damour-Solodukhin (DS) wormhole. We show that the photon sphere for the Schwarzschild-like wormhole presents both thin and thick accretion disks, even for the vanishing tidal forces. Moreover, we observe that r ph → ∞ as α → ∞, which constraints the α parameter to be sufficiently small and positive in order to respect Event Horizon Telescope observations. On the other hand, for the case of the RN wormhole, the photon sphere radius shrinks as Λ → ∞, as predicted by the effective potential. In addition to the accretion disks, we also probe the relativistic jets around the two wormhole solutions under consideration. Finally, with the help of star bulb microlensing, we approximate the radius of the wormhole shadow and find that for the Schwarzschild wormhole, R Sh ≈ r 0 for zero tidal forces and grows linearly with α. On the contrary, the shadow radius for charged wormholes slowly decreases with the growing DS parameter, Λ.

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An Exponential Shape Function for Wormholes in Modified Gravity*

Cited by 23 publications

References 83 publications

Tideless traversable wormholes surrounded by cloud of strings in f(R) gravity

Tideless traversable wormholes surrounded by cloud of strings in f(R) gravity

Embedding procedure and wormhole solutions in f(Q) gravity

Accretion flows around exotic tidal wormholes

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