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Junior E.L.B.,Federal University of Para | Rodrigues M.E.,Federal University of Para | Houndjo M.J.S.,Institute Of Mathematiques Et Of Science Physiques Imsp | Houndjo M.J.S.,University of Parakou
Journal of Cosmology and Astroparticle Physics | Year: 2015

We seek to obtain a new class of exact solutions of regular black holes in f(T) Gravity with non-linear electrodynamics material content, with spherical symmetry in 4D. The equations of motion provide the regaining of various solutions of General Relativity, as a particular case where the function f(T)=T. We developed a powerful method for finding exact solutions, where we get the first new class of regular black holes solutions in the f(T) Theory, where all the geometrics scalars disappear at the origin of the radial coordinate and are finite everywhere, as well as a new class of singular black holes. © 2015 IOP Publishing Ltd and Sissa Medialab srl . Source


Junior E.L.B.,Federal University of Para | Rodrigues M.E.,Federal University of Para | Houndjo M.J.S.,Institute Of Mathematiques Et Of Science Physiques Imsp | Houndjo M.J.S.,University of Parakou
Journal of Cosmology and Astroparticle Physics | Year: 2015

We investigate f(T) theory coupled with a nonlinear source of electrodynamics, for a spherically symmetric and static spacetime in 4D. We re-obtain the Born-Infeld and Reissner-Nordstrom-AdS solutions. We generalize the no-go theorem for any content that obeys the relationship 00=11 for the energy-momentum tensor and a given set of tetrads. Our results show new classes of solutions where the metrics are related through b(r)=-Na(r). We do the introductory analysis showing that solutions are that of asymptotically flat black holes, with a singularity at the origin of the radial coordinate, covered by a single event horizon. We also reconstruct the action for this class of solutions and obtain the functional form f(T)=f0(-T)(N+3)/[2(N+1)] and NED=0(-F)(N+3)/[2(N+1)]. Using the Lagrangian density of Born-Infeld, we obtain a new class of charged black holes where the action reads f(T)=-16βBI[1-1+(T/4βBI)]. © 2015 IOP Publishing Ltd and Sissa Medialab srl. Source


Setare M.R.,Payame Noor University | Houndjo M.J.S.,Federal University of Espirito Santo | Houndjo M.J.S.,Institute Of Mathematiques Et Of Science Physiques Imsp
Canadian Journal of Physics | Year: 2013

We investigate models of future finite-time singularities in f(T) theory, where T is the torsion scalar. The algebraic function f(T) is the teleparallel term, T, plus an arbitrary function, g(T). A suitable expression for the Hubble parameter is assumed and constraints are imposed to provide an expanding universe. Two parameters, β and Hs, that appear in the Hubble parameter are relevant in specifying the types of singularities. Differential equations of g(T) are established and solved, leading to algebraic f(T) models for each type of future finite-time singularity. Moreover, we take into account the viscosity in the fluid and discuss three interesting cases: constant viscosity, viscosity proportional to-T, and the general one where the viscosity is proportional to (-T)n/2, where n is a natural number. We see that for the first and second cases, in general, the singularities are robust against the viscous fluid, while for the general case, the Big Rip and the Big Freeze can be avoided from the effects of the viscosity for some values of n. © 2013 Published by NRC Research Press. Source


Setare M.R.,University of Kurdistan | Houndjo M.J.S.,Federal University of Espirito Santo | Houndjo M.J.S.,Institute Of Mathematiques Et Of Science Physiques Imsp
Canadian Journal of Physics | Year: 2013

We study particle production in a flat Friedmann-Robertson-Walker universe in the framework of f(T) gravity. An exact power-law solution is obtained by solving the Friedmann equations and assuming that matter is minimally coupled with gravitation. The torsion scalar, T, appears to plays the same role as the curvature (Ricci scalar) in general relativity (GR) and its modified theories, f(R). Particularly, in the phantom phase, we observe that the vacuum state corresponds to a vanishing torsion scalar and particle production becomes important as the torsion scalar diverges. This aspect not only provides the equivalence between teleparallel gravity and GR, but also between their respective modified versions, f(T) and f(R), in the view of massless particle production phenomenon when matter is minimally coupled with gravity. However, when the gravitational and scalar fields are not minimally coupled, it appears that this similarity between the teleparallel gravity and GR may break down, because the torsion scalar no longer has the same time-dependent expression as the Ricci scalar. © 2013 Published by NRC Research Press. Source


Hamani Daouda M.,Federal University of Espirito Santo | Hamani Daouda M.,University Abdou Moumouni | Rodrigues M.E.,Federal University of Espirito Santo | Houndjo M.J.S.,Federal University of Espirito Santo | Houndjo M.J.S.,Institute Of Mathematiques Et Of Science Physiques Imsp
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

We consider f(T) gravity for a Weitzenbock's spherically symmetric and static spacetime, where the metric is projected in the tangent space to the manifold, for a set of non-diagonal tetrads. The matter content is coupled through the energy-momentum tensor of an anisotropic fluid, generating various classes of new black hole and wormhole solutions. One of these classes is that of cold black holes. We also perform the reconstruction scheme of the algebraic function f(T) for two cases where the radial pressure is proportional to f(T) and its first derivative. © 2012 Elsevier B.V. Source

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