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Francisco Navarro-Lerida

Publications and source records attributed to Francisco Navarro-Lerida.

At least 19 recordsLinked to original sources

$SO(4)$ gauged $O(5)$ Skyrmion on $\mathbb{R}^4$

We have studied an $SO(4)$ gauged $O(5)$ Skyrmion on $\mathbb{R}^4$ which can be seen as a static soliton in $4+1$ dimensions. This is a sequel of the known $SO(D)$ gauged $O(D+1)$ Skyrmions on $\mathbb{R}^D$ in $D=2$ and in $D=3$, like which they are localised to an absolute scale and are topologically stable, their energies being bounded below by the winding number. In the absence of an analytic proof of existence some such solutions are constructed numerically. Two families of solutions are found, of which only one possesses a gauge decoupling limit. The curvatures of both of these solutions decay as $r^{-3}$, a property they share with the Yang-Mills instantons on $\mathbb{R}^4$.

hep-th↗

The effect of Skyrme--Chern-Simons dynamics on gauged Skyrmions in $2+1$ dimensions

We study the Skyrmion of the $SO(2)$ gauged $O(3)$ sigma model in $2+1$ dimensions in the presence of a Skyrme--Chern-Simons (SCS) term, and compare its properties with the corresponding properties of the Skyrmion in the presence of the usual Chern-Simons (CS) term. We find that these properties are qualitatively largely similar in both cases, meaning that the SCS density can be employed as an alternative to the CS term also in higher dimensions, most importantly in even dimensions where no CS term is defined, $e.g.,$ in $3+1$ dimensions. The SCS density employed here is defined in terms of the pair of $SO(2)\times SO(2)$ gauge fields and an auxiliary $O(5)$ Skyrme scalar, which is contracted to an effective $O(3)$ Skyrme scalar. Technically, this study maps the methods to be applied in higher dimensional examples.

hep-th↗

The role of the Callan-Witten anomaly density as a Chern-Simons term in Skyrme model

We consider axially symmetric solutions of the U(1) gauged Skyrme model supplemented with a Callan-Witten (CW) anomaly density term. The main properties of the solutions are studied, several specific features introduced by the presence of the CW term being identified. We find that the solitons possess a nonzero angular momentum proportional to the electric charge, which in addition to the usual Coulomb part, acquires an extra (topological) contribution from the CW term. Specifically, it is shown that the slope of mass/energy $M$ $vs.$ electric charge $Q_e$ and angular momentum $J$ can be both positive $and$ negative. Furthermore, it is shown that the gauged Skyrmion persists even when the quartic (Skyrme) kinetic term disappears.

hep-th↗

On the effects of the Chern-Simons term in an Abelian gauged Skyrme model in $d=4+1$ dimensions

We study an Abelian gauged $O(5)$ Skyrme model in $4+1$ dimensions, featuring the $F^4$ Maxwell and the Chern-Simons terms. Our aim is to expose the mechanism, discovered in the analogous Abelian gauged $O(3)$ Skyrme model in $2+1$ dimensions, which leads to the unusual relation of the mass-energy $E$ to the electric charge $Q_e$ and angular momentum $J$, and, to the change in the value of the "baryon number" $q$ due to the influence of the Abelian field on the Skyrmion. Chern-Simons dynamics together with the dynamics of the gauged Skyrme scalar, allows for solutions with varying asymptotic values of the magnetic field, resulting in these unusual properties listed. Numerical work is carried out on an effective one dimensional subsystem resulting from imposition of an enhaced radial symmetry on ${\mathbb R}^4$.

hep-th↗

$SO(2)$ gauged Skyrmions in $4+1$ dimensions

We study the simplest $SO(2)$ gauged $O(5)$ Skyrme models in $4+1$ (flat) dimensions. In the gauge decoupled limit, the model supports topologically stable solitons (Skyrmions) and after gauging, the static energy of the solutions is bounded from below by a "baryon number". The studied model features both Maxwell and Maxwell--Chern-Simons dynamics. The considered configurations are subject to bi-azimuthal symmetry in the ${\mathbb R}^4$ subspace resulting in a two dimensional subsystem, as well as subject to an enhanced symmetry relating the two planes in the ${\mathbb R}^4$ subspace, which results in a one dimensional subsystem. Numerical solutions are constructed in both cases. In the purely magnetic case, fully bi-azimuthal solutions were given, while electrically charged and spinning solutions were constructed only in the radial (enhanced symmetric) case, both in the presence of a Chern-Simons term, and in its absence. We find that, in contrast with the analogous models in $2+1$ dimensions, the presence of the Chern-Simons term in the model under study here results only in quantitative effects.

hep-th↗

Vortices of $SO(2)$ gauged Skyrmions in $2+1$ dimensions

Vortices the $SO(2)$ gauged planar Skyrme model, with a) only Maxwell, b) only Chern-Simons, and c) both Maxwell and Chern-Simons dynamics are studied systematically. In cases a) and b), where both models feature a single parameter $λ$ (the coupling of the potential term), the dependence of the energy on $λ$ is analysed. It is shown that the plots of the energy $vs.$ $λ$ feature discontinuities and branches. In case c), the emphasis is on the evolution of the topological charge, taking non-integer values. Throughout, the properties studied are contrasted with those of the corresponding Abelian Higgs models.

hep-th↗

On the topological charge of $SO(2)$ gauged Skyrmions in $2+1$ and $3+1$ dimensions

The question of the dependence of the topological charge $q$ of a gauged Skyrmion, on the gauge field, is studied quantitatively. Two examples, both gauged with $SO(2)$ are studied and contrasted: i) The $O(3)$ model in $2+1$ dimensions, and ii) The $O(4)$ model in $3+1$ dimensions. In case i), where the (usual) Chern-Simons (CS) term is present, the value of $q$ changes sign, going through zero. This evolution is tracked by a parameter characterising the solutions in the given theory. In case ii), in which dimensions no CS density is available, the evolution of $q$ is not observed.

hep-th↗

The effect of Chern-Simons dynamics on the energy of electrically charged and spinning vortices

We study the effect of a Chern-Simons term on the electrically charged and spinning solitons of several $U(1)$ gauged models in $2+1$ dimensions. These are vortices of complex scalar field theories, both with and without symmetry breaking dynamics, and the $O(3)$ Skyrme model. In all cases the gauge decoupling limits are also considered. It is well known that the effect of the Chern-Simons dynamics is to endow vortices with electric charge $Q_e$ and spin $J$, but our main aim here is to reveal a new feature: that the mass-energy $E$ of the electrically charged vortex can be lower than that of the electrically neutral one, in contrast to the usual monotonic increase of $E$ with $Q_e$. These effects of Chern-Simons dynamics were observed previously in $3+1$ dimensional systems, and the present results can be viewed as corroborating the latter. Moreover, the usual energy-spin relationship is likewise altered. We carry out a detailed quantitative analysis of azimuthally symmetric vortices and describe their qualitative features by constructing the solutions numerically.

hep-th↗

Rotating black holes with non-Abelian hair

We here review asymptotically flat rotating black holes in the presence of non-Abelian gauge fields. Like their static counterparts these black holes are no longer uniquely determined by their global charges. In the case of pure SU(2) Yang-Mills fields, the rotation generically induces an electric charge, while the black holes do not carry a magnetic charge. When a Higgs field is coupled, rotating black holes with monopole hair arise in the case of a Higgs triplet, while in the presence of a complex Higgs doublet the black holes carry sphaleron hair. The inclusion of a dilaton allows for Smarr type mass formulae.

hep-th↗

Electrically charged finite energy solutions of an $SO(5)$ and an $SU(3)$ Higgs-Chern-Simons--Yang-Mills-Higgs systems in $3+1$ dimensions

We study spherically symmetric finite energy solutions of two Higgs-Chern-Simons--Yang-Mills-Higgs (HCS-YMH) models in $3+1$ dimensions, one with gauge group $SO(5)$ and the other with $SU(3)$. The Chern-Simons (CS) densities are defined in terms of both the Yang-Mills (YM) and Higgs fields and the choice of the two gauge groups is made so they do not vanish. The solutions of the $SO(5)$ model carry only electric charge and zero magnetic charge, while the solutions of the $SU(3)$ model are dyons carrying both electric and magnetic charges like the Julia-Zee (JZ) dyon. Unlike the latter however, the electric charge in both models receives an important contribution from the CS dynamics. We pay special attention to the relation between the energies and charges of these solutions. In contrast with the electrically charged JZ dyon of the Yang-Mills-Higgs (YMH) system, whose mass is larger than that of the electrically neutral (magnetic monopole) solutions, the masses of the electrically charged solutions of our HCS-YMH models can be smaller than their electrically neutral counterparts in some parts of the parameter space. To establish this is the main task of this work, which is performed by constructing the HCS-YMH solutions numerically. In the case of the $SU(3)$ HCS-YMH, we have considered the question of angular momentum, and it turns out that it vanishes.

hep-th↗

Generalized dyons and magnetic dipoles: the issue of angular momentum

It is known that a non-Abelian magnetic monopole cannot rotate globally (although it may possess a nonzero angular momentum density). At the same time, the total angular momentum of a magnetic dipole equals the electric charge. In this work we question the generality of these results by considering a number of generalizations of the Georgi-Glashow model. We study two different types of finite energy, regular configurations: solutions with net magnetic charge and monopole-antimonopole pairs with zero net magnetic charge. These configurations are endowed with an electric charge and carry also a nonvanishing angular momentum density. However, we argue that the qualitative results found in the Georgi-Glashow model are generic and thus a magnetic monopole cannot spin as long as the matter fields feature the usual "monopole" asymptotic behaviour independently of the dynamics of the model. A study of the properties of the dyons and magnetic dipoles in some generalizations of the Georgi-Glashow model supplemented with higher order Skyrme-like terms in the gauge curvature and Higgs fields is given quantitatively.

hep-th↗

A non-Abelian Chern-Simons--Yang-Mills-Higgs system in 3+1 dimensions

We study spherically symmetric solutions of an $SO(5)$ Chern-Simons--Yang-Mills-Higgs system in $3+1$ dimensions. The Chern-Simons densities are defined in terms of both Yang-Mills fields and a $5$-component isomultiplet Higgs. The $SO(3)\times{SO(2)}$ solutions are analysed in a systematic way, by employing numerical methods. These finite energy configurations possess both electric and magnetic global charges, differing radically, however, from Julia-Zee dyons. When two or more of these Chern-Simons densities are present in the Lagrangian, solutions with vanishing electric charge but nonvanishing electrostatic potential may exist.

hep-th↗

Properties of rotating Einstein-Maxwell-Dilaton black holes in odd dimensions

We 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. Non-extremal 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.

gr-qc↗

Angular momentum-area proportionality of extremal charged black holes in odd dimensions

Extremal rotating 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.

gr-qc↗

Sequences of extremal radially excited rotating black holes

In Einstein-Maxwell-Chern-Simons theory the extremal Reissner-Nordström 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-Nordström solution. On the other hand, not all near horizon solutions are also realized as global solutions

gr-qc↗

Charged Rotating Black Holes in Higher Dimensions

In recent years higher-dimensional black holes have attracted much interest because of various developments in gravity and high energy physics. But whereas higher-dimensional charged static (Tangherlini) and uncharged rotating (Myers-Perry) black holes were found long ago, black hole solutions of Einstein-Maxwell theory, are not yet known in closed form in more than 4 dimensions, when both electric charge and rotation are present. Here we therefore study these solutions and those of Einstein-Maxwell-dilaton theory, by using numerical and perturbative methods, and by exploiting the existence of spacetime symmetries. The properties of these black holes reveal new interesting features, not seen in D=4. For instance, unlike the D=4 Kerr-Newman solution, they possess a non-constant gyromagnetic factor.

gr-qc↗

Nielsen-Olesen vortices for large Ginzburg-Landau parameter

Using analytic and numerical techniques Nielsen-Olesen vortices, which in the context of Ginzburg-Landau theory are known as Abrikosov vortices of type-II superconductors, are studied for large Ginzburg-Landau parameter $λ$. We show that their energy is equal to $(πn^2 /2)\logλ$ to leading order, where $n$ is the winding number of the vortex, and find that the limit of the gauge field can be expressed in terms of the modified Bessel function $K_1$. The leading terms of the asymptotic expansion of the solution are given, and the different contributions to the energy are analyzed.

hep-th↗

Extremal Charged Rotating Dilaton Black Holes in Odd Dimensions

Employing higher order perturbation theory, we find a new class of charged rotating black hole solutions of Einstein-Maxwell-dilaton theory with general dilaton coupling constant. Starting from the Myers-Perry solutions, we use the electric charge as the perturbative parameter, and focus on extremal black holes with equal-magnitude angular momenta in odd dimensions. We perform the perturbations up to 4th order for black holes in 5 dimensions and up to 3rd order in higher odd dimensions. We calculate the physical properties of these black holes and study their dependence on the charge and the dilaton coupling constant.

gr-qc↗