Person: Blázquez Salcedo, José Luis
Universidad Complutense de Madrid
Faculty / Institute
Now showing 1 - 10 of 18
PublicationCharged rotating black holes in Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant(Amer Physical Soc, 2017-03-13) 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. PublicationNon-Abelian Chern-Simons-Higgs vortices with a quartic potential(Amer Physical Soc, 2013-07-16) Blázquez Salcedo, José Luis; González Romero, Luis Manuel; Navarro Lerida, Francisco; Tchrakian, D. H.We have constructed numerically non-Abelian vortices in an SU(2) Chern-Simons-Higgs theory with a quartic Higgs potential. We have analyzed these solutions in detail by means of improved numerical codes and found some unexpected features we did not find when a sixth-order Higgs potential was used. The generic non-Abelian solutions have been generated by using their corresponding Abelian counterparts as initial guess. Typically, the energy of the non-Abelian solutions is lower than that of the corresponding Abelian one (except in certain regions of the parameter space). Regarding the angular momentum, the Abelian solutions possess the maximal value, although there exist non-Abelian solutions which reach that maximal value too. In order to classify the solutions it is useful to consider the non-Abelian solutions with asymptotically vanishing A_t component of the gauge potential, which may be labeled by an integer number m. For vortex number n = 3 and above, we have found uniqueness violation: two different nonAbelian solutions with all the global charges equal. Finally, we have investigated the limit of infinite Higgs self- coupling parameter and found a piecewise Regge-like relation between the energy and the angular momentum. PublicationStatic Einstein-Maxwell magnetic solitons and black holes in an odd dimensional AdS spacetime(Multidisciplinary Digital Publishing Institute, 2016-12) 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. PublicationSquashed, magnetized black holes in D=5 minimal gauged supergravity(Springer, 2018-02-09) 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. PublicationRotating objects in general relativity and gauge theories(Universidad Complutense de Madrid, 2014-10-31) Blázquez Salcedo, José Luis; González Romero, Luis Manuel; Navarro Lérida, Francisco PublicationThermodynamically stable asymptotically flat hairy black holes with a dilaton potential: the general case(Springer, 2021-02-26) Astefanesei, Dumitru; Blázquez Salcedo, José Luis; Gómez, Francisco; Rojas, RaúlWe extend the analysis, initiated in , of the thermodynamic stability of four-dimensional asymptotically flat hairy black holes by considering a general class of exact solutions in Einstein-Maxwell-dilaton theory with a non-trivial dilaton potential. We find that, regardless of the values of the parameters of the theory, there always exists a sub-class of hairy black holes that are thermodynamically stable and have the extremal limit well defined. This generic feature that makes the equilibrium configurations locally stable should be related to the properties of the dilaton potential that is decaying towards the spatial infinity, but behaves as a box close to the horizon. We prove that these thermodynamically stable solutions are also dynamically stable under spherically symmetric perturbations. PublicationCore-crust transition pressure for relativistic slowly rotating neutron stars(Amer Inst Physics, 2012) González Romero, Luis Manuel; Blázquez Salcedo, José LuisWe study the influence of core-crust transition pressure changes on the general dynamical properties of neutron star configurations. First we study the matching conditions in core-crust transition pressure region, where phase transitions in the equation of state causes energy density jumps. Then using a surface crust approximation, we can construct configurations where the matter is described by the equation of state of the core of the star and the core-crust transition pressure. We will consider neutron stars in the slow rotation limit, considering perturbation theory up to second order in the angular velocity so that the deformation of the star is also taken into account. The junction determines the parameters of the star such as total mass, angular and quadrupolar momentum. PublicationRemarks on the Taub-NUT solution in Chern–Simons modified gravity(Elsevier Science BV, 2017-08-10) 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. PublicationProbing the Ellis-Bronnikov wormhole geometry with a scalar field: clouds, waves and Q-balls(Elsevier Science BV, 2022-04-10) Blázquez Salcedo, José Luis; Dariescu, Marina Aura; Dariescu, Ciprian; Radu, Eugen; Stelea, CristianThe Ellis-Bronnikov solution provides a simple toy model for the study of various aspects of wormhole physics. In this work we solve the Klein-Gordon equation in this background and find an exact solution in terms of Heun's function. This may describe 'scalar clouds' (i.e. localized, particle-like configuration) or scalar waves. However, in the former case, the radial derivative of the scalar field is discontinuous at the wormhole's throat (except for the spherical case). This pathology is absent for a suitable scalar field self-interaction, and we provide evidence for the existence of spherically symmetric and spinning Q-balls in a Ellis-Bronnikov wormhole background. PublicationPhenomenological relations for axial quasinormal modes of neutron stars with realistic equations of state(Amer Physical Soc, 2013-05-31) Blázquez Salcedo, José Luis; González Romero, Luis Manuel; Navarro Lerida, FranciscoHere we investigate the axial w quasinormal modes of neutron stars for 18 realistic equations of state, most of them satisfying the 2M condition. In particular, we study the influence of the presence of hyperons and quarks in the core of the neutron stars. We have obtained that w modes can be used to distinguish between neutron stars with exotic matter and without exotic matter for compact enough stars. We present phenomenological relations for the frequency and damping times with the compactness of the neutron star for wI and wII modes showing the differences of the stars with exotic matter in the core. Also, we obtain a new phenomenological relation between the real part and the imaginary part of the frequency of the w quasinormal modes, which can be used to estimate the central pressure of the neutron stars. Finally, we study the low compactness limit configuration of fundamental wII modes, and the influence of changes in the core-crust transition pressure. To obtain these results we have developed a new method based on the exterior complex scaling technique with variable angle.