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I. Cabrera-Munguia

Publications and source records attributed to I. Cabrera-Munguia.

At least 19 recordsLinked to original sources
arXiv2026

Remarks on electrical Penrose process for magnetized Reissner-Nordström black hole

The energy extraction from a magnetized Reissner-Nordström black hole is analyzed within the framework of the electric Penrose mechanism. The presence of an external magnetic field induces an axisymmetric configuration and an ergosphere (the region where energy extraction is possible) arises, allowing for negative energy states even in an otherwise static spacetime. By analyzing the decay of particles at turning points of the radial motion, we derive the general expression for the efficiency of the process in terms of the metric coefficients and the electromagnetic potential. The resulting efficiencies are interpreted as Killing energy efficiencies associated with the local splitting process, while the escape of the positive energy fragment is treated as an additional effective-potential requirement. This formulation provides a direct criterion for identifying the ergoregions and we show that the magnetic field acts as a control parameter that governs both the configuration of the ergosphere and the efficiency of the process. In particular, analytical expressions for the critical magnetic fields that determine the onset and suppression of energy extraction are determined. Our results extend previous analysis of the electric Penrose process for magnetized configurations and clarify the role of the external field in enhancing or inhibiting energy extraction from charged black holes.

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arXiv2024

Energy extraction from the Reissner-Nordström de Sitter black hole

The energy extraction from an electrostatic black hole by the decay or splitting of electrically charged particles is analyzed. We determine the energetic conditions that make the extraction process viable and present a general expression for the efficiency in terms of the parameters of the electrostatic black hole and the decaying particles. We also examine the conditions that optimize the efficiency of the extraction process. We analyze two particular cases, the first one is the extraction process from a Reissner Nordström black hole, for charged test particles with nonvanishing angular momentum; the second one and more interesting corresponds to the energy extraction from a Reissner Nordström de Sitter black hole. For the latter there are two regions where the energy extraction is possible, the generalized ergosphere and a cosmological ergosphere induced by the cosmological horizon. Under certain conditions the two ergospheres get connected and cover the whole region between the event horizon and the cosmological horizon, and therefore the energy extraction is possible at any point in the vicinity of the black hole. Moreover, the efficiency of the energy extraction can be the same for different break up points and also there is the possibility of a different efficiency for the same break up point. The conditions that maximize the efficiency are determined as well.

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arXiv2022

Energy extraction in electrostatic extreme binary black holes

Relying on the Penrose process mechanism, we study the possibility of energy extraction from a binary system composed of two extreme electrostatic black holes (BHs) oppositely charged, separated by a strut described by Bonnor's metric (BM). We determined and plotted the generalized ergosphere that surrounds only one of the BH. We demonstrate the existence of non closed orbits of negative energy outside the event horizon; these orbits allow the possibility of energy extraction by particle disintegration from a system described by the BM. Besides we prove that the extraction process can occur when a charged test particle and the BH have opposite charges; also, we analyzed the efficiency of the process.

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arXiv2021

Quasinormal modes of the Hayward black hole surrounded by quintessence: scalar, electromagnetic and gravitational perturbations

We study the quasi-normal modes for scalar, electromagnetic, and gravitational axial perturbations in the Hayward regular black hole surrounded by quintessence (HBH-$ω_q$). Using the third--order WKB approximation we can determine the dependence of the quasi--normal modes on the parameters of the regular black hole and the parameters on the test fields. We also determine the greybody factor, giving transmission and reflection coefficients of the scattered wave through the effective potentials in the WKB approximation using numerical analysis.

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arXiv2021

Metric for two unequal extreme Kerr-Newman black holes

In the present paper, within the framework of stationary axisymmetric spacetimes, binary systems composed of two unequal co- and counter-rotating extreme Kerr-Newman black holes separated by a massless strut are reported. The metric describing both configurations is introduced in a closed analytical form in terms of five arbitrary parameters: the masses $M_{i}$, electric charges $Q_{i}$, and a coordinate distance $R$. We obtain novel results from these configurations; in particular, those related to the merging process.

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arXiv2021

Unequal binary configurations of interacting Kerr-Newman black holes

In this paper, binary systems of unequal Kerr-Newman black holes located on the axis and apart by a massless strut are investigated. After adopting a fitting parametrization, the conditions on the axis and the one eliminating the individual magnetic charges are solved exactly with the aim to obtain a 7-parametric asymptotically flat exact solution. It is also deduced explicit analytical formulas for each half-length horizon $σ_{i}$, $i = 1,2$, in terms of arbitrary physical Komar parameters: mass $M_{i}$, electric charge $Q_{i}$, angular momentum $J_{i}$, and a coordinate distance $R$. All the thermodynamical properties for the black holes as well as the interaction force related to the strut are also given in a concise way. Our analysis permits us to derive in detail the physical limits of the solution and introduce some scenarios where the strut is absent during the merger process.

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arXiv2020

Corotating dyonic binary black holes

This paper is dedicated to derive and study binary systems of identical corotating dyonic black holes separated by a massless strut -- two 5-parametric corotating binary black hole models endowed with both electric and magnetic charges-- where the dyonic black holes carrying equal/opposite electromagnetic charges in the first/second model satisfy the extended Smarr formula for the mass including the magnetic charge as a fourth conserved parameter.

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arXiv2020

Corotating binary systems of identical Kerr-Newman black holes

In the present paper binary configurations of identical corotating Kerr-Newman black holes separated by a massless strut are derived and studied. After solving the axis conditions and establishing the absence of magnetic charges in the solution, one gets two 4-parametric corotating binary black hole models endowed with electric charge, where each source contains equal/opposite electric charge in the first/second configuration. Since the black hole horizons are given by concise expressions in terms of physical parameters, all their thermodynamical properties satisfying the Smarr relation for the mass are also obtained. We discuss the physical limits of both models.

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arXiv2020

Geodesics of Hayward black hole surrounded by quintessence

Basing on the ideas used by Kiselev, we study the Hayward black hole surrounded by quintessence. By setting for the quintessence state parameter at the special case of $ω=-\frac{2}{3}$, using the metric of the black hole surrounded by quintessence and the definition of the effective potential, we analyzed in detail the null geodesics for different energies. We also analyzed the horizons of the Hayward black hole surrounded by quintessence as well as the shadow of the black hole.

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arXiv2018

Extreme binary black holes in a physical representation

Stationary axisymmetric binary systems of unequal co and counter-rotating extreme Kerr black holes apart by a conical singularity are studied. Both solutions are well identified as two $3$-parametric subfamilies of the Kinnersley-Chitre metric, and fully depicted by Komar parameters: the two masses $M_{1}$ and $M_{2}$, and a coordinate distance $R$, where the angular momenta $J_{1}$ and $J_{2}$ are functions of these parameters. Our physical representation allows us to identify some limits and novel physical properties.

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arXiv2018

Unequal binary configurations of interacting Kerr black holes

Stationary axisymmetric binary configurations of unequal Kerr sources with a massless strut among them are developed in a physical representation. In order to describe interacting black holes, the axis conditions in the most general case are solved analytically deriving the corresponding $5$-parametric asymptotically flat exact solution. In addition, we obtain concise formulas for the black hole horizons, the interaction force, as well as the thermodynamical characteristics of each source in terms of physical Komar parameters: mass $M_{i}$, angular momentum $J_{i}$, and coordinate distance $R$, where such parameters are contained inside of the coefficients of a cubic equation which can be interpreted as a dynamical law for interacting black holes with struts. Some limits are obtained and discussed.

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arXiv2017

Corotating two-body system of identical Kerr sources

A binary system of identical corotating Kerr sources is studied after deriving the corresponding 3-parametric asymptotically flat exact solution. Both sources are apart from each other by means of a massless strut (conical singularity). In the context of black holes, the analytical functional form of each horizon σ is expressed in terms of arbitrary Komar physical parameters: mass M, angular momentum J (with parallel spin), and the coordinate distance R between the center of each horizon. Later on, all the thermodynamical properties related to the horizon are depicted by concise formulae. Finally, the extreme limit case is obtained as a 2-parametric subclass of Kinnersley-Chitre metric.

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arXiv2017

Binary system of unequal counterrotating Kerr-Newman sources

Stationary axisymmetric binary systems of unequal counterrotating Kerr-Newman sources with a massless strut in between are studied. By means of the choice of a suitable parametrization, the axis conditions and the absence of individual magnetic charges are fulfilled; thus, the entire metric reduces to a 6-parametric asymptotically flat exact solution. Later on, with the purpose to describe interacting black holes, the analytic functional form of the horizon half-length parameter $σ_{k}$ is obtained explicitly in terms of physical Komar parameters: mass $M_{k}$, electric charge $Q_{k}$, angular momentum $J_{k}$, and coordinate distance $R$, where the seven physical parameters satisfy a simple algebraic relation. Finally, in the limit of extreme black holes, the full metric is derived in a closed analytical form, and a study on the absence or appearance of naked singularities off the axis is presented.

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arXiv2014

On naked singularities in the extreme double Reissner-Nordström solution

We present a quite simple analytical study on the appearance or absence of naked singularities in binary systems. As an example we consider the double Reissner-Nordström solution and fix the conditions it should satisfy in order to avoid or develop singular surfaces off the axis. The proof shows that singular surfaces appear as a consequence of the presence of negative masses in the solution.

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arXiv2014

Exact solution for a binary system of unequal counter-rotating black holes

A complete solution describing a binary system constituted by two unequal counter-rotating black holes with a massless strut inbetween is presented. It is expressed in terms of four arbitrary parameters: the half length of the two rods representing the black hole horizons sigma1 and sigma2, the total mass M, and the relative distance R between the centers of the horizons. The explicit form of this solution in terms of physical parameters, i.e., the Komar masses M1 and M2, the Komar angular momenta per unit mass a1 and a2, having a1 and a2 opposite signs, and the coordinate distance R, led us to a 4-parameter subclass of solutions in which a set of five physical parameters satisfy a simple algebraic relation. Moreover, the interaction force, provided by the strut, between the black holes results to be of same form as it is for the static double-Schwarzschild case.

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arXiv2014

Opposite charged two-body system of identical counter-rotating black holes

A 4-parametric exact solution describing a two-body system of identical Kerr-Newman counter-rotating black holes endowed with opposite electric/magnetic charges is presented. The axis conditions are solved in order to really describe two black holes separated by a massless strut. Moreover, the explicit form of the horizon half length parameter sigma in terms of physical Komar parameters, i.e., the Komar mass M, electric charge QE, angular momentum J, and a coordinate distance R is derived. Additionally, magnetic charges QB arise from the rotation of electrically charged black holes. As a consequence, in order to account for the contribution to the mass of the magnetic charge, the usual Smarr mass formula should be generalized, as it is proposed by A. Tomimatsu, Prog. Theor. Phys. 72, 73 (1984).

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arXiv2014

Generalized black diholes

A 5-parametric exact solution, describing a binary system composed of identical counter-rotating black holes endowed with opposite electromagnetic charges, is constructed. The addition of the angular momentum parameter to the static Emparan-Teo dihole model introduces magnetic charges into this two-body system. The solution can be considered as an extended model for describing generalized black diholes as dyons. We derive the explicit functional form of the horizon half-length parameter $σ$ as a function of the Komar parameters: Komar mass $M$, electric/magnetic charge $Q_{E }/ Q_{B}$, angular momentum $J$, and a coordinate distance $R$, where the parameters $(M, J, Q_E, Q_B, R)$ characterize the upper constituent of the system, while $(M, -J, -Q_E, -Q_B, R)$ are associated with the lower one. The addition of magnetic charges enhances the standard Smarr mass formula in order to take into account their contribution to the mass. The solution contains, as particular cases, two solutions already discussed in the literature.

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