Canfora, F., Gomberoff, A., Oh, S. H., Rojas, F., & Salgado-Rebolledo, P. (2019). Meronic Einstein-Yang-Mills black hole in 5D and gravitational spin from isospin effect. J. High Energy Phys., (6), 32 pp.
Abstract: We construct an analytic black hole solution in SU(2) Einstein-Yang-Mills theory in five dimensions supporting a Meron field. The gauge field is proportional to a pure gauge and has a non-trivial topological charge. The would-be singularity at the Meron core gets shielded from the exterior by the black hole horizon. The metric has only one integration constant, namely, its ADM mass, which is shown to be finite once an appropriate boundary term is added to the action. The thermodynamics is also worked out, and a first-order phase transition, similar to the one occurring in the Reissner-Nordstrom case is identified. We also show that the solution produces a spin from isospin effect, i.e., even though the theory is constructed out of bosons only, the combined system of a scalar field and this background may become fermionic. More specifically, we study scalar excitations in this purely bosonic background and find that the system describes fermionic degrees of freedom at spatial infinity. Finally, for the asymptotically AdS(5) case, we study its consequences in the context of the AdS/CFT correspondence.
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Canfora, F., Oh, S. H., & Salgado-Rebolledo, P. (2017). Gravitational catalysis of merons in Einstein-Yang-Mills theory. Phys. Rev. D, 96(8), 10 pp.
Abstract: We construct regular configurations of the Einstein-Yang-Mills theory in various dimensions. The gauge field is of meron-type: it is proportional to a pure gauge (with a suitable parameter lambda determined by the field equations). The corresponding smooth gauge transformation cannot be deformed continuously to the identity. In the three-dimensional case we consider the inclusion of a Chern-Simons term into the analysis, allowing lambda to be different from its usual value of 1/2. In four dimensions, the gravitating meron is a smooth Euclidean wormhole interpolating between different vacua of the theory. In five and higher dimensions smooth meron-like configurations can also be constructed by considering warped products of the three-sphere and lower-dimensional Einstein manifolds. In all cases merons (which on flat spaces would be singular) become regular due to the coupling with general relativity. This effect is named “gravitational catalysis of merons”.
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Canfora, F. E., Dudal, D., Justo, I. F., Pais, P., Salgado-Rebolledo, P., Rosa, L., et al. (2017). Double nonperturbative gluon exchange: An update on the soft-Pomeron contribution to pp scattering. Phys. Rev. C, 96(2), 8 pp.
Abstract: We employ a set of recent, theoretically motivated fits to nonperturbative unquenched gluon propagators to check on how far double gluon exchange can be used to describe the soft sector of pp scattering data (total and differential cross section). In particular, we use the refined Gribov-Zwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwall-type gluon propagator (as motivated from Dyson-Schwinger equations) in conjunction with a perturbative quark-gluon vertex, next to a model based on the nonperturbative quark-gluon Maris-Tandy vertex, popular from Bethe-Salpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with older ISR and more recent TOTEM and ATLAS data. The lower the value of total energy root s, the better the results appear to be.
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Caroca, R., Concha, P., Fierro, O., Rodriguez, E., & Salgado-Rebolledo, P. (2018). Generalized Chern-Simons higher-spin gravity theories in three dimensions. Nucl. Phys. B, 934, 240–264.
Abstract: The coupling of spin-3 gauge fields to three-dimensional Maxwell and AdS-Lorentz gravity theories is presented. After showing how the usual spin-3 extensions of the Ad S and the Poincare algebras in three dimensions can be obtained as expansions of sl (3, R) algebra, the procedure is generalized so as to define new higher-spin symmetries. Remarkably, the spin-3 extension of the Maxwell symmetry allows one to introduce a novel gravity model coupled to higher-spin topological matter with vanishing cosmological constant, which in turn corresponds to a flat limit of the AdS-Lorentz case. We extend our results to define two different families of higher-spin extensions of three-dimensional Einstein gravity. (C) 2018 The Authors. Published by Elsevier B.V.
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Caroca, R., Concha, P., Rodriguez, E., & Salgado-Rebolledo, P. (2018). Generalizing the bms(3) and 2D-conformal algebras by expanding the Virasoro algebra. Eur. Phys. J. C, 78(3), 15 pp.
Abstract: By means of the Lie algebra expansion method, the centrally extended conformal algebra in two dimensions and the bms3 algebra are obtained from the Virasoro algebra. We extend this result to construct new families of expanded Virasoro algebras that turn out to be infinite-dimensional lifts of the so-called Bk, Ck and Dk algebras recently introduced in the literature in the context of (super) gravity. We also show how some of these new infinite-dimensional symmetries can be obtained from expanded Kac-Moody algebras using modified Sugawara constructions. Applications in the context of three-dimensional gravity are briefly discussed.
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Concha, P., Merino, N., Miskovic, O., Rodriguez, E., Salgado-Rebolledo, P., & Valdivia, O. (2018). Asymptotic symmetries of three-dimensional Chern-Simons gravity for the Maxwell algebra. J. High Energy Phys., (10), 22 pp.
Abstract: We study a three-dimensional Chern-Simons gravity theory based on the Maxwell algebra. We find that the boundary dynamics is described by an enlargement and deformation of the bms(3) algebra with three independent central charges. This symmetry arises from a gravity action invariant under the local Maxwell group and is characterized by presence of Abelian generators which modify the commutation relations of the super-translations in the standard bms(3) algebra. Our analysis is based on the charge algebra of the theory in the BMS gauge, which includes the known solutions of standard asymptotically flat case. The field content of the theory is different than the one of General Relativity, but it includes all its geometries as particular solutions. In this line, we also study the stationary solutions of the theory in ADM form and we show that the vacuum energy and the vacuum angular momentum of the stationary configuration are influenced by the presence of the gravitational Maxwell field.
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