Current-carrying cosmic strings in scalar-tensor gravities

Ferreira, Cristine Nunes; Guimarães, M. E. X.; Helayël-Neto, J. A.

doi:10.1016/s0550-3213(00)00282-0

Cited by 35 publications

(36 citation statements)

References 21 publications

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“…The external structure Now, we study the behavior of the external solution in the case where the dilaton is time-dependent [36] and a Chern-Simons coupling is taken into account. The solutions for β(r) and γ(r) are the same as obtained recently [6] and read as…”

Section: Screwed Cosmic String Model With Chern-simons Couplingmentioning

confidence: 93%

“…In this paper, we study the cosmic string configuration in the context of scalar-tensor theories of gravity [6] with torsion [7,8,9] and analyse their role in the geometric and topological features of the cosmic string solution. A cosmic string is what is called a topological defect and corresponds to a regular, classical solution to a gauge field theory which arises when a symmetry of the theory is spontaneously broken.…”

Section: Introductionmentioning

confidence: 99%

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Lorentz-breaking effects in scalar-tensor theories of gravity

2005

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In this work, we study the effects of breaking Lorentz symmetry in scalar-tensor theories of gravity taking torsion into account. We show that a space-time with torsion interacting with a Maxwell field by means of a Chern-Simons-like term is able to explain the optical activity in syncrotron radiation emitted by cosmological distant radio sources. Without specifying the source of the dilaton-gravity, we study the dilaton-solution. We analyse the physical implications of this result in the Jordan-Fierz frame. We also analyse the effects of the Lorentz breaking in the cosmic string formation process. We obtain the solution corresponding to a cosmic string in the presence of torsion by keeping track of the effects of the Chern-Simons coupling and calculate the charge induced on this cosmic string in this framework. We also show that the resulting charged cosmic string gives us important effects concerning the background radiation.The optical activity in this case is also worked out and discussed.

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Section: Screwed Cosmic String Model With Chern-simons Couplingmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Lorentz-breaking effects in scalar-tensor theories of gravity

2005

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“…Notable exceptions include a handful of studies in f (R) gravity [75,76,78], teleparallel theories [79,80], brane worlds [81,82], Kaluza-Klein models [83,84], Lovelock [85,86], Gauss-Bonnet [87][88][89], BornInfeld [90][91][92] and bimetric [93][94][95][96][97][98][99][100] gravity theories, and a few other, less mainstream, alternatives [101][102][103][104][105], while more comprehensive bodies of work exist for strings in scalar-tensor theories [106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121], including string theoryinspired dilation gravity [122,123], and gravitational th...…”

Section: Introductionmentioning

confidence: 99%

Cosmic strings in $$f\left( R,L_m\right) $$ f R , L m gravity

Harkó

Lake

2015

Eur. Phys. J. C

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We consider Kasner-type static, cylindrically symmetric interior string solutions in the f (R, L m ) theory of modified gravity. The physical properties of the string are described by an anisotropic energy-momentum tensor satisfying the condition T t t = T z z ; that is, the energy density of the string along the z-axis is equal to minus the string tension. As a first step in our study we obtain the gravitational field equations in the f (R, L m ) theory for a general static, cylindrically symmetric metric, and then for a Kasner-type metric, in which the metric tensor components have a power law dependence on the radial coordinate r . String solutions in two particular modified gravity models are investigated in detail. The first is the so-called "exponential" modified gravity, in which the gravitational action is proportional to the exponential of the sum of the Ricci scalar and matter Lagrangian, and the second is the "self-consistent model", obtained by explicitly determining the gravitational action from the field equations under the assumption of a power law dependent matter Lagrangian. In each case, the thermodynamic parameters of the string, as well as the precise form of the matter Lagrangian, are explicitly obtained.

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“…The properties and interaction of the superconducting cosmic strings with astrophysical magnetic fields have been studied in [28][29][30]. Also, superconducting cosmic strings have been investigated in dilaton gravity [31][32][33], and in BransDicke theory [34]. These solutions are not black holes, and represent spacetimes with conic singularities.…”

Section: Introductionmentioning

confidence: 99%

Three dimensional nonlinear magnetic AdS solutions through topological defects

et al. 2015

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Inspired by large applications of topological defects in describing different phenomena in physics, and considering the importance of three dimensional solutions in AdS/CFT correspondence, in this paper we obtain magnetic anti-de Sitter solutions of nonlinear electromagnetic fields. We take into account three classes of nonlinear electrodynamic models; first two classes are the well-known BornInfeld like models including logarithmic and exponential forms and third class is known as the power Maxwell invariant nonlinear electrodynamics. We investigate the effects of these nonlinear sources on three dimensional magnetic solutions. We show that these asymptotical AdS solutions do not have any curvature singularity and horizon. We also generalize the static metric to the case of rotating solutions and find that the value of the electric charge depends on the rotation parameter. Finally, we consider the quadratic Maxwell invariant as a correction of Maxwell theory and we investigate the effects of nonlinearity as a correction. We study the behavior of the deficit angle in presence of these theories of nonlinearity and compare them with each other. We also show that some cases with negative deficit angle exists which are representing objects with different geometrical structure. We also show that in case of the static only magnetic field exists whereas by boosting the metric to rotating one, electric field appears too.

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Current-carrying cosmic strings in scalar-tensor gravities

Abstract: We study the modifications on the metric of an isolated self-gravitating bosonic superconducting cosmic string in a scalar-tensor gravity in the weak-field approximation. These modifications are induced by an arbitrary coupling of a massless scalar field to the usual tensorial field *

Cited by 35 publications

References 21 publications

Lorentz-breaking effects in scalar-tensor theories of gravity

Lorentz-breaking effects in scalar-tensor theories of gravity

Cosmic strings in $$f\left( R,L_m\right) $$ f R , L m gravity

Three dimensional nonlinear magnetic AdS solutions through topological defects

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