arXiv subjects

Daniel Flores-Alfonso

Publications and source records attributed to Daniel Flores-Alfonso.

23 records · Page 2Linked to original sources

arXiv2019

Topological Characterization of Higher Dimensional Charged Taub-NUT Instantons

Recently, we have shown that non-selfdual self-gravitating dyonic fields with magnetic mass generalize the Dirac monopole. The unique topological index, which characterizes the field, is a four dimensional analogue of the famous monopole configuration. An unexpected result of this analysis is that the electric parameter can only take certain discrete values as a consequence of applying the path integral approach to quantize the magnetic flux. Here, we show how this result can be generalized to higher dimensions, considering a special type of inhomogeneous geometries. Our results apply to a vast range of theories and situations in which topological charges are present. For concreteness, we focus here on Lovelock--Maxwell solutions and show that the magnetic flux corresponds to a topological excitation and the electric flux becomes discrete.

hep-th↗

arXiv2019

Charged Taub-NUT solution in Lovelock gravity with generalized Wheeler polynomials

Wheeler's approach to finding exact solutions in Lovelock gravity has been predominantly applied to static spacetimes. This has led to a Birkhoff's theorem for arbitrary base manifolds in dimensions higher than four. In this work, we generalize the method and apply it to a stationary metric. Using this perspective, we present a Taub-NUT solution in eight-dimensional Lovelock gravity coupled to Maxwell fields. We use the first-order formalism to integrate the equations of motion in the torsion-free sector. The Maxwell field is presented explicitly with general integration constants, while the background metric is given implicitly in terms of a cubic algebraic equation for the metric function. We display precisely how the NUT parameter generalizes Wheeler polynomials in a highly nontrivial manner.

gr-qc↗

arXiv2019

Extended Thermodynamics of Self-Gravitating Skyrmions

A modification of the hedgehog ansatz has recently led to novel exact black hole solutions with selfgravitating SU(2) Skyrme fields. Considering a negative cosmological constant the black holes are not asymptotically anti-de Sitter (AdS) but rather asymptote to an AdS version of Barriola--Vilenkin spacetime. We examine the thermodynamics of the system interpreting the cosmological constant as a bulk pressure. We use the standard counterterm method to obtain a finite Euclidean action. For a given coupling of the matter action, the system behaves as does a charged AdS black hole in the fixed charged ensemble. We find that in the limit case when the Skyrme model becomes a nonlinear sigma model the system exhibits a first order phase transition of Hawking--Page type. The universality class of these Einstein--Skyrme black holes is that of van der Waals.

gr-qc↗

arXiv2018

Chern Index of Taub-Bolt instantons in Einstein-Born-Infeld gravity

Partition functions can be calculated by saddle point approximations whenever regular solutions exist, as they dominate the path integral. We examine a regular Taub-Bolt dyon of Einstein-Born-Infeld theory which has electric and magnetic flux proportional to each other. Magnetic flux is found to be essentially a winding number and the electric flux turns out to be indexed by it.

hep-th↗

arXiv2017

Topological Quantum Numbers of Dyonic Fields over Taub-Bolt

We study the global structure of dyonic fields on a Taub-Bolt background, and compare our results with similar fields over Taub-NUT and Schwarzschild spaces. It is shown that the electric and magnetic charges are quantized and lead to a classification of dyonic Taub-Bolt configurations. The quantization condition for the magnetic charge is similar to that of Dirac's monopole.

gr-qc↗