Collapsing Wormholes Sustained by Dustlike Matter

Kashargin, Pavel E.; Sushkov, Sergey V.

doi:10.3390/universe6100186

Cited by 10 publications

(20 citation statements)

References 41 publications

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“…Of special interest are attempts to obtain wormholes with such a realistic source as dust (a perfect fluid with zero pressure) due to their possible relation to the matter-dominated stage of expansion in our Universe [12,70]. With spherical symmetry, one then naturally uses the famous Lemaître-Tolman-Bondi (LTB) solution to the Einstein equations [14][15][16] or its generalization with radial electric or magnetic fields [71][72][73][74][75][76].…”

Section: Cosmological Wormholes 31 General Observationsmentioning

confidence: 99%

Rotating Melvin-like Universes and Wormholes in General Relativity

2020

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We find a family of exact solutions to the Einstein–Maxwell equations for rotating cylindrically symmetric distributions of a perfect fluid with the equation of state p=wρ (|w|<1), carrying a circular electric current in the angular direction. This current creates a magnetic field along the z axis. Some of the solutions describe geometries resembling that of Melvin’s static magnetic universe and contain a regular symmetry axis, while some others (in the case w>0) describe traversable wormhole geometries which do not contain a symmetry axis. Unlike Melvin’s solution, those with rotation and a magnetic field cannot be vacuum and require a current. The wormhole solutions admit matching with flat-space regions on both sides of the throat, thus forming a cylindrical wormhole configuration potentially visible for distant observers residing in flat or weakly curved parts of space. The thin shells, located at junctions between the inner (wormhole) and outer (flat) regions, consist of matter satisfying the Weak Energy Condition under a proper choice of the free parameters of the model, which thus forms new examples of phantom-free wormhole models in general relativity. In the limit w→1, the magnetic field tends to zero, and the wormhole model tends to the one obtained previously, where the source of gravity is stiff matter with the equation of state p=ρ.

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Section: Cosmological Wormholes 31 General Observationsmentioning

confidence: 99%

Rotating Melvin-like Universes and Wormholes in General Relativity

2020

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“…with constant β. The values of α can be restricted to −1.5 ≤ α ≤ 1, so that we can describe, if necessary, different types of cosmological fluids, such as stiff matter [55], radiation [56], dust [57], dark energy [58] and phantom fluid [59,60]. On the other hand, β 1 in order to guarantee anisotropy and 0 in order to avoid singularities.…”

Section: Traversable Wormholes: Metric Energy-momentum Tensor Travers...mentioning

confidence: 99%

Unimodular Gravity Traversable Wormholes

Moraes¹,

Agrawal²,

Mishra³

2022

Preprint

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Wormholes are outstanding solutions of Einstein's General Relativity. They were worked out in the late 1980's by Morris and Thorne, who have figured out a recipe that wormholes must obey in order to be traversable, that is, safely crossed by travelers. A remarkable feature is that General Relativity Theory wormholes must be filled by exotic matter, which Morris and Thorne define as matter satisfying −p r > ρ, in which p r is the radial pressure and ρ is the energy density of the wormhole. In the present letter, we introduce, for the first time in the literature, traversable wormhole solutions of Einstein's Unimodular Gravity Theory. Unimodular Gravity was proposed by Einstein himself as the theory for which the field equations are the traceless portion of General Relativity field equations. Later, Weinberg has shown that this approach elegantly yields the solution of the infamous cosmological constant problem. The wormhole solutions here presented satisfy the metric conditions of "traversability" and remarkably evade the exotic matter condition, so we can affirm that Unimodular Gravity wormholes can be filled by ordinary matter.

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“…A special case of functions F (R) and f (R) satisfying the throat conditions ( 17) and ( 18) was considered in [55]. In this paper, we consider the general case without specifying the functions F (R) and f (R) and test the traversability of the models.…”

Section: Possible Wormhole Throatsmentioning

confidence: 99%

“…Its properties were further investigated, for example, in [52][53][54]. An attempt to obtain a wormhole using a special choice of arbitrary functions in this solution was undertaken in [55].…”

Section: Introductionmentioning

confidence: 99%

Magnetized dusty black holes and wormholes

Бронников¹,

Kashargin²,

Sushkov³

2021

Preprint

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We consider the generalized Tolman solution of general relativity, describing the evolution of a spherical dust cloud in the presence of an external electric or magnetic field. The solution contains three arbitrary functions f (R) , F (R) and τ 0 (R) , where R is a radial coordinate in the comoving reference frame. The solution splits into three branches corresponding to hyperbolic (f > 0 ), parabolic ( f = 0 ) and elliptic (f < 0 ) types of motion. In such models, we study the possible existence of wormhole throats defined as spheres of minimum radius at a fixed time instant, and prove the existence of throats in the elliptic branch under certain conditions imposed on the arbitrary functions. It is further shown that the normal to a throat is a timelike vector (except for the instant of maximum expansion, when this vector is null), hence a throat is in general located in a T-region of space-time. Thus if such a dust cloud is placed between two empty (Reissner-Nordström or Schwarzschild) space-time regions, the whole configuration is a black hole rather than a wormhole. However, dust clouds with throats can be inscribed into closed isotropic cosmological models filled with dust to form wormholes which exist for a finite period of time and experience expansion and contraction together with the corresponding cosmology. Explicit examples and numerical estimates are presented. The possible traversability of wormhole-like evolving dust layers is established by a numerical study of radial null geodesics.

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Collapsing Wormholes Sustained by Dustlike Matter

Cited by 10 publications

References 41 publications

Rotating Melvin-like Universes and Wormholes in General Relativity

Rotating Melvin-like Universes and Wormholes in General Relativity

Unimodular Gravity Traversable Wormholes

Magnetized dusty black holes and wormholes

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