Brane-world stars and (microscopic) black holes

We study stars in the brane-world by employing the principle of minimal geometric deformation and find that brane-world black hole metrics with a tidal charge are consistently recovered in a suitable limit. This procedure allows us to determine the tidal charge as a function of the black hole ADM mass (and brane tension). A minimum mass for semiclassical microscopic black holes can then be derived, with a relevant impact for the description of black hole events at the LHC.Comment: LaTeX, 11 pages, 2 figures. Final version to appear in PL

The Minimal Geometric Deformation Approach: a brief introduction

We review the basic elements of the Minimal Geometric Deformation approach in details. This method has been successfully used to generate brane-world configurations from general relativistic perfect fluid solutions.Comment: Brief review; minor corrections; references adde

Anisotropic solutions by gravitational decoupling

We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the star surface with the outer Schwarzschild space-time are studied in great details, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent.Comment: 20 pages, 4 figures; references and typos corrected; final version to match the EPJC versio

A causal Schwarzschild-de Sitter interior solution by gravitational decoupling

We employ the minimal geometric deformation approach to gravitational decoupling (MGD- decoupling) in order to build an exact anisotropic version of the Schwarzschild interior solution in a space-time with cosmological constant. Contrary to the well-known Schwarzschild interior, the matter density in the new solution is not uniform and possesses subluminal sound speed. It therefore satisfies all standard physical requirements for a candidate astrophysical object.Comment: 15 pages, 6 figure

Non-uniform Braneworld Stars: an Exact Solution

The first exact interior solution to Einstein's field equations for a static and non-uniform braneworld star with local and non-local bulk terms is presented. It is shown that the bulk Weyl scalar ${\cal U}(r)$ is always negative inside the stellar distribution, in consequence it reduces both the effective density and the effective pressure. It is found that the anisotropy generated by bulk gravity effect has an acceptable physical behaviour inside the distribution. Using a Reissner-N\"{o}rdstrom-like exterior solution, the effects of bulk gravity on pressure and density are found through matching conditions.Comment: 22 pages, 3 figures, version to be published in International Journal of Modern Physics D (IJMPD

Hairy black holes by gravitational decoupling

Black holes with hair represented by generic fields surrounding the central source of the vacuum Schwarzschild metric are examined under the minimal set of requirements consisting of i) the existence of a well defined event horizon and ii) the strong or dominant energy condition for the hair outside the horizon. We develop our analysis by means of the gravitational decoupling approach. We find that trivial deformations of the seed Schwarzschild vacuum preserve the energy conditions and provide a new mechanism to evade the no-hair theorem based on a primary hair associated with the charge generating these transformations. Under the above conditions i) and ii), this charge consistently increases the entropy from the minimum value given by the Schwarzschild geometry. As a direct application, we find a non-trivial extension of the Reissner-Nordstrom black hole showing a surprisingly simple horizon. Finally, the non-linear electrodynamics generating this new solution is fully specified.Comment: 11 pages, 4 figure

Einstein-Klein-Gordon by gravitational decoupling

We investigate how a spherically symmetric scalar field can modify the Schwarzschild vacuum solution when there is no exchange of energy-momentum between the scalar field and the central source of the Schwarzschild metric. This system is described by means of the gravitational decoupling by Minimal Geometric Deformation (MGD-decoupling), which allows us to show that, under the MGD paradigm, the Schwarzschild solution is modified in such a way that a naked singularity appears.Comment: 16 pages, 2 figures. arXiv admin note: text overlap with arXiv:1804.0346

A CFD-based Approach to Predict Explosion Overpressure: A Comparison to Current Methods

A CFD-based approach has been developed in this work to predict the overpressure produced during an explosion. An adiabatic exothermal reaction allows computing the explosion energy release. To validate the proposed CFD approach, overpressure predictions based on this methodology are compared with results produced with the TNObased method. It is demonstrated that the physics adopted in our model produces satisfactory predictions in the open area. The CFD simulations were carried out in the ANSYS CFX tool. The source of energy corresponds to the one produced by a stoichiometric proportion in reactants without energy generation. The explosion analysis considered that explosion occurs geometrically as a sequence of control volumes. Thus, the explosion in a volume is assumed to occur when the maximum pressure is achieved in the previous control volume. This way, the explosion is propagated and it is shown that it is equivalent to conventional predicting methods

Black holes by gravitational decoupling

We investigate how a spherically symmetric fluid modifies the Schwarzschild vacuum solution when there is no exchange of energy-momentum between the fluid and the central source of the Schwarzschild metric. This system is described by means of the gravitational decoupling realised via the minimal geometric deformation approach, which allows us to prove that the fluid must be anisotropic. Several cases are then explicitly shownComment: New section with a regular hairy black hole solution; references adde

Isotropization and change of complexity by gravitational decoupling

We employ the gravitational decoupling appro- ach for static and spherically symmetric systems to develop a simple and powerful method in order to (a) continuously isotropize any anisotropic solution of the Einstein field equa- tions, and (b) generate new solutions for self-gravitating dis- tributions with the same or vanishing complexity factor. A few working examples are given for illustrative purposes