Non-Abelian Rotating Black Holes in 4- and 5-Dimensional Gauged Supergravity

We present new supersymmetric black-hole solutions of the 4- and 5-dimensional gauged supergravity theories that one obtains by dimensional reduction on $T^{5}$ and $T^{6}$ of Heterotic supergravity with a triplet of Yang-Mills fields. The new ingredient of our solutions is the presence of dyonic non-Abelian fields which allows us to obtain a generalization of the BMPV black hole with two independent angular momenta and the first example of a supersymmetric, rotating, asymptotically-flat black hole with a regular horizon in 4 dimensions.Comment: 41 pages. Version accepted in JHE

Black holes in string theory with higher-derivative corrections

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de lectura: 23-09-2020The low-energy limit of superstring theories admits a description in terms of an effective eld theory for its massless modes. The corresponding action is given by a double perturbative expansion in gs, the string coupling, and in 0, the square of the string length. The leading term of this expansion is given by one of the different ten-dimensional supergravity theories, whereas subleading terms involve terms of higher order in derivatives. The work presented in this thesis is the result of a research program that starts with the study of supersymmetric solutions of gauged supergravity and reaches the summit with the understanding of the effects produced by the 0 corrections to solutions of the heterotic superstring e ective action. This thesis is divided in two parts. The rst one focuses on the supersymmetric solutions of a minimal extension of the STU model of N = 1; d = 5 supergravity whose main interest lies on the fact that it can be obtained as a toroidal compacti cation of ten-dimensional N = 1 supergravity coupled to a triplet of SU(2) gauge elds. Concretely, we construct and study solutions describing black holes and smooth horizonless geometries with non-trivial Yang-Mills elds. The understanding of this type of solutions from the framework of string theory serves as a motivation for the work of the second part of the thesis, which is devoted to the study of solutions of the effective action of the heterotic string at rst order in 0. The latter does not simply coincide with the action of N = 1; d = 10 supergravity coupled to a Yang-Mills vector multiplet as the Green-Schwarz anomaly cancellation mechanism and supersymmetry enforce us to introduce additional terms in the action. These terms are constructed out of the spin connection with torsion given by the eld strength associated to the Kalb-Ramond 2-form and their contributions to the equations of motion are analogous to those of the Yang-Mills elds. This fact is exploited to construct analytic supersymmetric black-hole solutions with 0 corrections. The most important lesson to extract from our results is that the mass and the conserved charges of the black holes do get modi ed by the 0 corrections. This is what one would expect on physical grounds as the corrections act in the string equations of motion as effective sources of energy, momentum and charge. This information is crucial to establish a correspondence between the parameters that characterize the effective or coarse-grained description (the black hole) and those that characterize the microscopic system of string theory that it describes. The effects on the charges introduced by the higher-derivative corrections has a major impact in the understanding of the so-called small black holes, which are an effective description of a fundamental string with winding and momentum charges. Small black holes are singular solutions with vanishing horizon area in the supergravity approximation. It has long been believed that higher-derivative corrections would be able to stretch the horizon, making the solution regular. Our results reveal that this is not the case at rst order in 0, and that previous regularizations of heterotic small black holes actually describe a different microscopic system which is already regular in the supergravity approximation. The last chapter of the thesis contains the computation of the most general correction to the four-dimensional Kerr solution when the Einstein-Hilbert term is supplemented with higher curvature terms up to cubic order, including the possibility of having dynamical couplings. This general set-up includes, as a particular case, the corrections predicted by the heterotic superstring effective actio

Corrections to AdS5_5 Black Hole Thermodynamics from Higher-Derivative Supergravity

We study four-derivative corrections to five-dimensional minimal gauged supergravity. We evaluate the on-shell action of the AdS$_5$ black hole solution with two independent angular momenta and one electric charge at linear order in the corrections. After imposing supersymmetry, we are able to recast the action in terms of the supersymmetric chemical potentials and match the result obtained from the dual superconformal index on the second sheet. To achieve this, we exploit the freedom to implement field redefinitions to recast the action in a much simpler form, as well as the fact that the two-derivative solution is enough. We use the on-shell action to determine the corrections to the black hole thermodynamics, including those to the entropy and the charges. We then specialize to the supersymmetric and extremal case and find a simple expression for the microcanonical entropy. In particular, for the case with one independent angular momentum the corrections are entirely encoded in the dual superconformal anomaly coefficients. We corroborate this result for the entropy by constructing the corrected near-horizon solution and applying Wald's formula.Comment: 52 pages; v2: new results on general angular momenta and Legendre transform of the susy on-shell action added, clarifications added, typos fixed, references adde

Boundary terms and conserved charges in higher-derivative gauged supergravity

We address some issues in higher-derivative gauged supergravity with Chern-Simons terms, focusing on the five-dimensional case. We discuss the variational problem with Dirichlet boundary conditions as well as holographic renormalization in asymptotically locally AdS spacetimes, and derive the corresponding boundary terms. We then employ Wald's formalism in order to define conserved charges associated to local symmetries (diffeomorphisms and U(1) gauge transformations), taking into account the effect of generic gauge Chern-Simons terms. We prove that the first law of black hole mechanics and the quantum statistical relation hold in this setup. Chern-Simons terms also lead us to distinguish between Noether charges and Page (or Komar) charges which satisfy the Gauss law. We make use of the latter to compute corrections to the angular momentum and electric charge of the supersymmetric black hole in AdS$_5$ from its corrected near-horizon geometry. This also allows us to derive the microcanonical form of the entropy as a function of the conserved charges relying entirely on the near-horizon geometry. Finally, we comment on four-derivative gauged supergravity in four dimensions, showing that field redefinitions permit to simplify the action at linear order in the corrections, so that the equations of motion are those of the two-derivative theory.Comment: 39 page

Black Hole Multipoles in Higher-Derivative Gravity

We consider a broad family of higher-derivative extensions of four-dimensional Einstein gravity and study the multipole moments of rotating black holes therein. We carefully show that the various definitions of multipoles carry over from general relativity, and compute these multipoles for higher-derivative Kerr using the ACMC expansion formalism. We obtain the mass $M_{n}$ and current $S_{n}$ multipoles as a series expansions in the dimensionless spin; in some cases we are able to resum these series into closed-form expressions. Moreover, we observe the existence of intriguing relations between the corrections to the parity-odd multipoles $S_{2n}\neq 0$ and $M_{2n+1}\neq 0$ that break equatorial symmetry, and the parity-preserving corrections that only modify $S_{2n+1}$ and $M_{2n}$. Further, we comment on the higher-derivative corrections to multipole ratios for Kerr, and we discuss the phenomenological implications of the corrections to the multipole moments for current and future gravitational wave experiments.Comment: 31 pages + Appendix, 13 figures, Mathematica notebook with all expansions used in the pape

On a family of α′-corrected solutions of the Heterotic Superstring effective action

We compute explicitly the first-order in α′ corrections to a family of solutions of the Heterotic Superstring effective action that describes fundamental strings with momentum along themselves, parallel to solitonic 5-branes with Kaluza-Klein monopoles (Gibbons-Hawking metrics) in their transverse space. These solutions correspond to 4-charge extremal black holes in 4 dimensions upon dimensional reduction on T6. We show that some of the α′ corrections can be cancelled by introducing solitonic SU(2) × SU(2) Yang-Mills fields, and that this family of α′-corrected solutions is invariant under α′-corrected T-duality transformations. We study in detail the mechanism that allows us to compute explicitly these α′ corrections for the ansatz considered here, based on a generalization of the ’t Hooft ansatz to hyperKähler spacesThis work has been supported in part by the MINECO/FEDER, UE grants FPA2015-66793-P and FPA2015-63667-P, by the Italian INFN and by the Spanish Research Agency (Agencia Estatal de Investigación) through the grant IFT Centro de Excelencia Severo Ochoa SEV-2016-0597. AR is supported by “Centro de Excelencia Internacional UAM/CSI

Partition functions on slightly squashed spheres and flux parameters

We argue that the conjectural relation between the subleading term in the small-squashing expansion of the free energy of general three-dimensional CFTs on squashed spheres and the stress-tensor three-point charge t4 proposed in arXiv:1808.02052: FSε3(3)(0)=1630π4CTt4, holds for an infinite family of holographic higher-curvature theories. Using holographic calculations for quartic and quintic Generalized Quasi-topological gravities and general-order Quasi-topological gravities, we identify an analogous analytic relation between such term and the charges t2 and t4 valid for five-dimensional theories: FSε5(3)(0)=215π6CT[1+340t2+23630t4]. We test both conjectures using new analytic and numerical results for conformally-coupled scalars and free fermions, finding perfect agreementThe work of PB was supported by the Simons foundation through the It From Qubit Simons collaboration. PAC was supported by the KU Leuven grant “Bijzonder Onderzoeksfonds C16/16/005 — Horizons in hoge-energie fysica”. The work of RAH is supported by the Natural Sciences and Engineering Research Council of Canada through the Banting Postdoctoral Fellowship program. The work of VAP was supported by CONICET. The work of AR was supported by a FPI-UAM pre-doctoral gran

Evaluation of the Library and Information Science degree of the Polytechnical University of Valencia

The evaluation process of the Library and Information Science’s (LIS) Degree of the Polytechnic University of Valencia is described. The development of the Spanish LIS’s academic studies and the university education evaluation procedure according to the responsible Spanish agency (Aneca) are explained; and, finally, the most noticeable results of the evaluation of the UPV Documentation’s studies are exposed