Person: Blázquez Salcedo, José Luis
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First Name
José Luis
Last Name
Blázquez Salcedo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física Teórica
Area
Física Teórica
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11 results
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Now showing 1 - 10 of 11
Item Angular momentum – area – proportionality of extremal charged black holes in odd dimensions(Physics Letters B, 2013) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lerida, FranciscoExtremal rotating cohomogeneity-1 black holes in Einstein-Maxwell theory feature two branches. On the branch emerging from the Myers-Perry solutions their angular momentum is proportional to their horizon area, while on the branch emerging from the Tangherlini solutions their angular momentum is proportional to their horizon angular momentum. The transition between these branches occurs at a critical value of the charge, which depends on the value of the angular momentum. However, when a dilaton is included, the angular momentum is always proportional to the horizon area.Item Remarks on the Taub-NUT solution in Chern–Simons modified gravity(Physics letters B, 2017) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lérida, Francisco; Radu, EugenWe construct a generalization of the AdS charged rotating black holes with two equal magnitude angular momenta in five-dimensional minimal gauged supergravity. In addition to the mass, electric charge and angular momentum, the new solutions possess an extra-parameter associated with a non-zero magnitude of the magnetic potential at infinity. In contrast with the known cases, these new black holes possess a non-trivial zero-horizon size limit which describes a one parameter family of spinning charged solitons. All configurations reported in this work approach asymptotically an AdS(5) spacetime in global coordinates and are free of pathologies.Item Radial perturbations of the scalarized Einstein-Gauss-Bonnet black holes(Physical Review D, 2018) Blázquez Salcedo, José Luis; Doneva, Daniela D.; Kunz, Jutta; Yazadyiev, Stoytcho S.Recently a new class of scalarized black holes in Einstein-Gauss-Bonnet (EGB) theories was discovered. What is special for these black hole solutions is that the scalarization is not due to the presence of matter, but it is induced by the curvature of spacetime itself. Moreover, more than one branch of scalarized solutions can bifurcate from the Schwarzschild branch, and these scalarized branches are characterized by the number of nodes of the scalar field. The next step is to consider the linear stability of these solutions, which is particularly important due to the fact that the Schwarzschild black holes lose stability at the first point of bifurcation. Therefore we here study in detail the radial perturbations of the scalarized EGB black holes. The results show that all branches with a nontrivial scalar field with one or more nodes are unstable. The stability of the solutions on the fundamental branch, whose scalar field has no radial nodes, depends on the particular choice of the coupling function between the scalar field and the Gauss-Bonnet invariant. We consider two particular cases based on the previous studies of the background solutions. If this coupling has the form used in [D. D. Doneva and S. S. Yazadjiev, Phys. Rev. Lett. 120, 131103 (2018)] the fundamental branch of solutions is stable, except for very small masses. In the case of a coupling function quadratic in the scalar field [H. O. Silva, J. Sakstein, L. Gualtieri, T. P. Sotiriou, and E. Berti, Phys. Rev. Lett. 120, 131104 (2018)], though, the whole fundamental branch is unstable.Item Squashed, magnetized black holes in D=5 minimal gauged supergravity(Journal of high energy physics, 2018) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lérida, Francisco; Radu, EugenWe construct a new class of black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant. These configurations are cohomogeneity-1, with two equal-magnitude angular momenta. In the generic case, they possess a non-vanishing magnetic potential at infinity with a boundary metric which is the product of time and a squashed three-dimensional sphere. Both extremal and non-extremal black holes are studied. The non-extremal black holes satisfying a certain relation between electric charge, angular momenta and magnitude of the magnetic potential at infinity do not trivialize in the limit of vanishing event horizon size, becoming particle-like (non-topological) solitonic configurations. Among the extremal black holes, we show the existence of a new one-parameter family of supersymmetric solutions, which bifurcate from a critical Gutowski-Reall configuration.Item Sequences of extremal radially excited rotating black holes(Physical Review Letters, 2014) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lerida, Francisco; Radu, EugenIn the Einstein-Maxwell-Chern-Simons theory the extremal Reissner-Nordstrom solution is no longer the single extremal solution with vanishing angular momentum, when the Chern-Simons coupling constant reaches a critical value. Instead a whole sequence of rotating extremal J = 0 solutions arises, labeled by the node number of the magnetic U(1) potential. Associated with the same near horizon solution, the mass of these radially excited extremal solutions converges to the mass of the extremal Reissner-Nordstrom solution. On the other hand, not all near horizon solutions are also realized as global solutions.Item Static Einstein-Maxwell magnetic solitons and black holes in an odd dimensional AdS spacetime(Entropy, 2016) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lérida, Francisco; Radu, EugenWe construct a new class of Einstein-Maxwell static solutions with a magnetic field in D-dimensions (with D >= 5 an odd number), approaching at infinity a globally Anti-de Sitter (AdS) spacetime. In addition to the mass, the new solutions possess an extra-parameter associated with a non-zero magnitude of the magnetic potential at infinity. Some of the black holes possess a non-trivial zero-horizon size limit, which corresponds to a solitonic deformation of the AdS background.Item Charged rotating black holes in Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant(Physical review D, 2017) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lérida, Francisco; Radu, EugenWe consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant.. Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magnitude angular momenta, which approach at infinity a globally anti-de Sitter background. We find that the generic solutions share a number of basic properties with the known Cvetic, Lu, and Pope black holes which have lambda = 1. New features occur as well; for example, when the Chern-Simons coupling constant exceeds a critical value, the solutions are no longer uniquely determined by their global charges. Moreover, the black holes possess radial excitations which can be labelled by the node number of the magnetic gauge potential function. Solutions with small values of. possess other distinct features. For instance, the extremal black holes there form two disconnected branches, while not all near-horizon solutions are associated with global solutions.Item Quasinormal modes of Einstein-Gauss-Bonnet-dilaton black holes(Physical Review D, 2017) Blázquez Salcedo, José Luis; Khoo, Fech Scen; Kunz, JuttaWe study quasinormal modes of static Einstein-Gauss-Bonnet-dilaton black holes. Both axial and polar perturbations are considered and studied from l = 0 to l = 3. We emphasize the difference in the spectrum between the Schwarzschild solutions and dilatonic black holes. At large Gauss-Bonnet coupling constant, a small secondary branch of black holes is present, when the dilaton coupling is sufficiently strong. The modes of the primary branch can differ from the Schwarzschild modes up to 10%. The secondary branch is unstable and possesses long-lived modes. We address the possible effects of these modes on future observations of gravitational waves emitted during the ringdown phase of astrophysical black holes.Item Properties of rotating Einstein-Maxwell-dilaton black holes in odd dimensions(Physical Review D, 2014) Blázquez Salcedo, José Luis; Kunz, Jutta; Navarro Lerida, FranciscoWe investigate rotating Einstein-Maxwell-dilaton (EMd) black holes in odd dimensions. Focusing on black holes with equal-magnitude angular momenta, we determine the domain of existence of these black holes. Nonextremal black holes reside with the boundaries determined by the static and the extremal rotating black holes. The extremal EMd black holes show proportionality of their horizon area and their angular momenta. Thus the charge does not enter. We also address the Einstein-Maxwell case, where the extremal rotating black holes exhibit two branches. On the branch emerging from the Myers-Perry solutions, their angular momenta are proportional to their horizon area, whereas on the branch emerging from the static solutions their angular momenta are proportional to their horizon angular momenta. Only subsets of the near-horizon solutions are realized globally. Investigating the physical properties of these EMd black holes, we note that one can learn much about the extremal rotating solutions from the much simpler static solutions. The angular momenta of the extremal black holes are proportional to the area of the static ones for the Kaluza-Klein value of the dilaton coupling constant, and remain analogous for other values. The same is found for the horizon angular velocities of the extremal black holes, which possess an analogous behavior to the surface gravity of the static black holes. The gyromagnetic ratio is rather well approximated by the "static" value, obtained perturbatively for small angular momenta.Item Perturbed black holes in Einstein-dilaton-Gauss-Bonnet gravity: stability, ringdown, and gravitational-wave emission(Physical Review D, 2016) Blázquez Salcedo, José Luis; Macedo, Caio F.B.; Cardoso, Vitor; Ferrari, Valeria; Gualtieri, Leonardo; Khoo, Fech Scen; Kunz, Jutta; Pani, PaoloGravitational waves emitted by distorted black holes-such as those arising from the coalescence of two neutron stars or black holes-carry not only information about the corresponding spacetime but also about the underlying theory of gravity. Although general relativity remains the simplest, most elegant, and viable theory of gravitation, there are generic and robust arguments indicating that it is not the ultimate description of the gravitational universe. Here, we focus on a particularly appealing extension of general relativity, which corrects Einstein's theory through the addition of terms which are second order in curvature: the topological Gauss-Bonnet invariant coupled to a dilaton. We study gravitational-wave emission from black holes in this theory and (i) find strong evidence that black holes are linearly (mode) stable against both axial and polar perturbations, (ii) discuss how the quasinormal modes of black holes can be excited during collisions involving black holes, and finally (iii) show that future ringdown detections with a large signal-to-noise ratio would improve current constraints on the coupling parameter of the theory.