Matching conditions in the Einstein-Cartan theory of gravitation

Arkuszewski, W.; Kopczyński, Wojciech; Ponomariev, V. N.

doi:10.1007/bf01629248

Cited by 65 publications

(63 citation statements)

References 7 publications

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“…where (−) represents the internal region and (+) corresponds to the external region around ρ = ρ 0 [23,24]. For a supermassive U(1) gauge cosmic string in the Bogomonl'ny limit where q 2 = 8λ and µ = πη 2 , thus we find that 2 √ 2 ηq…”

Section: External Solution and The Matched Conditionsmentioning

confidence: 80%

Supermassive screwed cosmic string in dilaton gravity

Bezerra

Ferreira

Cuesta

2006

Class. Quantum Grav.

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The early Universe might have undergone phase transitions at energy scales much higher than the one corresponding to the Grand Unified Theories (GUT) scales. At these higher energy scales, the transition at which gravity separated from all other interactions; the socalled Planck era, more massive strings called supermassive cosmic strings, could have been produced, with energy of about 1019 GeV . The dynamics of strings formed with this energy scale cannot be described by means of the weak-field approximation, as in the standard procedure for ordinary GUT cosmic strings. As suggested by string theories, at this extreme energies, gravity may be transmitted by some kind of scalar field (usually called the dilaton) in addition to the tensor field of Einstein's theory of gravity. It is then permissible to tackle the issue regarding the dynamics of supermassive cosmic strings within this framework. With this aim we obtain the gravitational field of a supermassive screwed cosmic string in a scalartensor theory of gravity. We show that for the supermassive configuration exact solutions of scalar-tensor screwed cosmic strings can be found in connection with the Bogomol'nyi limit. We show that the generalization of Bogomol'nyi arguments to the Brans-Dicke theory is possible when torsion is present and we obtain an exact solution in this supermassive regime, with the dilaton solution obtained by consistency with internal constraints. * valdir@fisica.ufpb.br † crisnfer@cefetcampos.br ‡ hermanjc@cbpf.br

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Section: External Solution and The Matched Conditionsmentioning

confidence: 80%

Supermassive screwed cosmic string in dilaton gravity

Bezerra

Ferreira

Cuesta

2006

Class. Quantum Grav.

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“…To our knowledge, the literature concerning this line of research is somewhat scarce, 17 see e.g., [101]. Torsion is perhaps one of the important consequences of coupling gravity to fermions.…”

Section: Discussionmentioning

confidence: 99%

“…However, a curvature singularity as the final fate of a gravitational collapse process can still occur even if explicit spin-torsion and spin-spin repulsive interactions [101] are taken into account. The argument that has been put forward is that since photons neither produce nor interact with the space-time torsion, the causal structure of an EC manifold, determined by light signals, is the same as in GR.…”

Section: Introductionmentioning

confidence: 99%

Einstein–Cartan gravitational collapse of a homogeneous Weyssenhoff fluid

et al. 2014

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We consider the gravitational collapse of a spherically symmetric homogeneous matter distribution consisting of a Weyssenhoff fluid in the presence of a negative cosmological constant. Our aim is to investigate the effects of torsion and spin averaged terms on the final outcome of the collapse. For a specific interior space-time setup, namely the homogeneous and isotropic FLRW metric, we obtain two classes of solutions to the field equations where depending on the relation between spin source parameters, (i) the collapse procedure culminates in a space-time singularity or (ii) it is replaced by a non-singular bounce. We show that, under certain conditions, for a specific subset of the former solutions, the formation of trapped surfaces is prevented and thus the resulted singularity could be naked. The curvature singularity that forms could be gravitationally strong in the sense of Tipler. Our numerical analysis for the latter solutions shows that the collapsing dynamical process experiences four phases, so that two of which occur at the pre-bounce and the other two at post-bounce regimes. We further observe that there can be found a minimum radius for the apparent horizon curve, such that the main outcome of which is that there exists an upper bound for the size of the collapsing body, below which no horizon forms throughout the whole scenario.

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“…(3.14) in the limit turns out to be 15) which is expected to contribute to the junction conditions. The remaining volume integral V must be handled with care, since it will give a non-zero contribution to the junction conditions.…”

Section: Junction Conditions From the Field Equationsmentioning

confidence: 99%

“…We thank F. W. Hehl for bringing to our attention Ref. [15] where junction conditions for a boundary layer between two spin sources in the bulk were discussed. This work was partially funded by FONDECYT grants 1040921, 1051056, 1061291 and 3060016.…”

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confidence: 99%

Junction conditions in general relativity with spin sources

2006

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The junction conditions for General Relativity in the presence of domain walls with intrinsic spin are derived in three and higher dimensions. A stress tensor and a spin current can be defined just by requiring the existence of a well defined volume element instead of an induced metric, so as to allow for generic torsion sources. In general, when the torsion is localized on the domain wall, it is necessary to relax the continuity of the tangential components of the vielbein. In fact it is found that the spin current is proportional to the jump in the vielbein and the stress-energy tensor is proportional to the jump in the spin connection. The consistency of the junction conditions implies a constraint between the direction of flow of energy and the orientation of the spin. As an application, we derive the circularly symmetric solutions for both the rotating string with tension and the spinning dust string in three dimensions. The rotating string with tension generates a rotating truncated cone outside and a flat spacetime with inevitable frame dragging inside. In the case of a string made of spinning dust, in opposition to the previous case no frame dragging is present inside, so that in this sense, the dragging effect can be "shielded" by considering spinning instead of rotating sources. Both solutions are consistently lifted as cylinders in the four-

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Matching conditions in the Einstein-Cartan theory of gravitation

Abstract: In this paper matching and junction conditions in the Einstein-Cartan theory are presented. It is shown that a Weyssenhoff fluid sphere collapses to a singularity.

Cited by 65 publications

References 7 publications

Supermassive screwed cosmic string in dilaton gravity

Supermassive screwed cosmic string in dilaton gravity

Einstein–Cartan gravitational collapse of a homogeneous Weyssenhoff fluid

Junction conditions in general relativity with spin sources

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