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
Identifiers
6 results
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Item Polar modes and isospectrality of Ellis-Bronnikov wormholes(Physical review D, 2023) Azad, Bahareh; Blázquez Salcedo, José Luis; Chew, Xiao Yan; Kunz, Jutta; Yeom, Dong-hanWe consider polar perturbations of static Ellis-Bronnikov wormholes and derive the coupled set of perturbation equations for the gravitational and the scalar field. For massless wormholes the perturbations decouple, and we obtain two identical master equations for the scalar and gravitational modes, which moreover agree with the master equation for the axial modes. Consequently there is isospectrality with threefold degenerate modes. For a finite mass of the background wormhole solutions, the equations are coupled. We then obtain two distinct branches of polar quasinormal modes for a given multipole number l, associated with the presence of the two types of fields. We calculate the quasinormal mode frequencies and decay rates for the branches with l = 2, 3 and 4. For a given l the real frequencies of the two branches get the closer, the higher the multipole number gets.Item Non-Abelian Chern-Simons-Higgs vortices with a quartic potential(Physical review D, 2013) 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.Item Polar quasi-normal modes of neutron stars with equations of state satisfying the 2 M_0 constraint(Physical review D, 2014) Blázquez Salcedo, José Luis; González Romero, Luis Manuel; Navarro Lérida, F.In this paper, we analyze the quasinormal mode spectrum of realistic neutron stars by studying the polar modes. In particular, we calculate the fundamental mode (f mode), the fundamental pressure mode (p mode), and the fundamental curvature mode (wI mode) for 15 different equations of state satisfying the 2 M_0 constraint, most of them containing exotic matter. Since f and p modes couple to matter perturbations, the influence of the presence of hyperons and quarks in the core of the neutron stars is more significant than for the axial component. We present phenomenological relations, which are compatible with previous results, for the frequency and damping time with the compactness of the neutron star. We also consider new phenomenological relations between the frequency and damping time of the wI mode and the f mode. These new relations are independent of the equation of state and could be used to estimate the central pressure, mass, or radius and eventually constrain the equation-of-state of neutron stars. To obtain these results, we have developed a new method based on the exterior complex scaling technique with a variable angle.Item Core-crust transition pressure for relativistic slowly rotating neutron stars(Towards New Paradigms: proceeding of the Spanish Relativity Meeting 2011, 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.Item Phenomenological relations for axial quasinormal modes of neutron stars with realistic equations of state(Physical review D, 2013) 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.Item New model of relativistic slowly rotating neutron star with surface layer crust: application to giant glitches of Vela Pulsar(Journal of physics: Conference series, 2011) González Recio, José Luis; Blázquez Salcedo, José LuisIntroducing a surface layer of matter on the edge of a neutron star in slow rigid rotation, we analyze, from an intrinsic point of view, the junction conditions that must be satisfied between the interior and exterior solutions of the Einstein equations. In our model the corecrust transition pressure arise as an essential parameter in the description of a configuration. As an application of this formalism, we describe giant glitches of the Vela pulsar as a result of variations in the transition pressure, finding that these small changes are compatible with the expected temperature variations of the inner crust during glitch time