The String Landscape, the Swampland, and the Missing Corner

We give a brief overview of the string landscape and techniques used to construct string compactifications. We then explain how this motivates the notion of the swampland and review a number of conjectures that attempt to characterize theories in the swampland. We also compare holography in the context of superstrings with the similar, but much simpler case of topological string theory. For topological strings, there is a direct definition of topological gravity based on a sum over a "quantum gravitational foam." In this context, holography is the statement of an identification between a gravity and gauge theory, both of which are defined independently of one another. This points to a missing corner in string dualities which suggests the search for a direct definition of quantum theory of gravity rather than relying on its strongly coupled holographic dual as an adequate substitute (Based on TASI 2017 lectures given by C. Vafa)

Open string multi-branched and Kahler potentials

We consider type II string compactifications on Calabi-Yau orientifolds with fluxes and D-branes, and analyse the F-term scalar potential that simultaneously involves closed and open string modes. In type IIA models with D6-branes such potential can be directly computed by integrating out Minkowski three-forms. The result shows a multi-branched structure along the space of lifted open string moduli, in which discrete shifts in special Lagrangian and Wilson line deformations are compensated by changes in the RR flux quanta. The same sort of discrete shift symmetries are present in the superpotential and constrain the Kahler potential. As for the latter, inclusion of open string moduli breaks the factorisation between complex structure and Kahler moduli spaces. Nevertheless, the 4d Kahler metrics display a set of interesting relations that allow to rederive the scalar potential analytically. Similar results hold for type IIB flux compactifications with D7-brane Wilson lines.Comment: 60 pages, one figure. v2 minor corrections and references adde

No go for a flow

We prove that a very large class of 15502 general Argyres-Douglas theories can- not admit a UV lagrangian which ows to them via the Maruyoshi-Song supersymmetry enhancement mechanism. We do so by developing a computer program which brute-force lists, for any given 4d N = 2 superconformal theory TIR, all possible UV candidate su- perconformal lagrangians TUV satisfying some necessary criteria for the supersymmetry enhancement to happen. We argue that this is enough evidence to conjecture that it is impossible, in general, to find new examples of Maruyoshi-Song lagrangians for generalized Argyres-Douglas theories. All lagrangians already known are, on the other hand, recovered and confirmed in our scan. Finally, we also develop another program to compute efficiently Coulomb branch spectrum, masses, couplings and central charges for (G, G’) Argyres-Douglas theories of arbitrarily high rankThe work of FC is supported by the ERC Consolidator Grant STRINGFLATION under the HORIZON 2020 grant agreement no. 647995. AM would like to thank Florent Baume, Emilio Ambite and Marcos Ramírez for the support with the HYDRA cluster in the IFT. AM received funding from “La Caixa” Foundation (ID 100010434) with fellowship code LCF/BQ/IN18/11660045 and from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk lodowska-Curie grant agreement No. 71367

Fitting fermion masses and mixings in F-theory GUTs

Journal of High Energy Physics 2016.3 (2016): 126 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)We analyse the structure of Yukawa couplings in local SU(5) F-theory models with E7 enhancement. These models are the minimal setting in which the whole flavour structure for the MSSM charged fermions is encoded in a small region of the entire compactification space. In this setup the E7 symmetry is broken down to SU(5) by means of a 7-brane T-brane background, and further to the MSSM gauge group by means of a hypercharge flux that also implements doublet-triplet splitting. At tree-level only one family of quarks and charged leptons is massive, while the other two obtain hierarchically smaller masses when stringy non-perturbative effects are taken into account. We find that there is a unique E7 model with such hierarchical flavour structure. The relative simplicity of the model allows to perform the computation of Yukawa couplings for a region of its parameter space wider than previous attempts, obtaining realistic fermion masses and mixings for large parameter regions. Our results are also valid for local models with E8 enhancement, pointing towards a universal structure to describe realistic fermion masses within this frameworkThis work has been partially supported by the grant FPA2012-32828 from the MINECO, the REA grant agreement PCIG10-GA-2011-304023 from the People Programme of FP7 (Marie Curie Action), the ERC Advanced Grant SPLE under contract ERC-2012-ADG-20120216-320421 and the grant SEV-2012-0249 of the “Centro de Excelencia Severo Ochoa” Programme. F.C. is supported through a fellowship of the international programme “La Caixa-Severo Ochoa”. F.M. is supported by the Ram´on y Cajal programme through the grant RYC-2009-05096. G.Z. is supported through a grant from “Campus Excelencia Internacional UAM+CSIC”. F.M. would like to thank HKUST IAS, the CERN TH Division, the Aspen Center for Theoretical Physics (supported through the NSF grant PHY-1066293) and UW-Madison for hospitality and support during the completion of this wor

A landscape of orientifold vacua

We present a vast landscape of O3/O7 orientifolds that descends from the famous set of complete intersection Calabi-Yau threefolds (CICY). We give distributions of topological data relevant for phenomenology such as the orientifold-odd Hodge numbers, the D3-tadpole, and multiplicities of O3 and O7-planes. Somewhat surprisingly, almost all of these orientifolds have conifold singularities whose deformation branches are projected out by the orientifolding. However, they can be resolved, so most of the orientifolds actually descend from a much larger and possibly new set of CY threefolds that can be reached from the CICYs via conifold transitions. We observe an interesting class of $\mathcal{N}=1$ geometric transitions involving colliding O-planes. Finally, as an application, we use our dataset to produce examples of orientifolds that satisfy the topological requirements for the existence of ultra-light throat axions (\textit{thraxions}) as proposed in \cite{Hebecker:2018yxs}. The database can be accessed at https://www.desy.de/~westphal/orientifold_webpage/cicy_orientifolds.htmlComment: 35 pages, 3 appendices, 5 figure

Gaugino condensation and small uplifts in KKLT

In the first part of this note we argue that ten dimensional consistency requirements in the form of a certain tadpole cancellation condition can be satisfied by KKLT type vacua of type IIB string theory. We explain that a new term of non-local nature is generated dynamically once supersymmetry is broken and ensures cancellation of the tadpole. It can be interpreted as the stress caused by the restoring force that the stabilization mechanism exerts on the volume modulus. In the second part, we explain that it is surprisingly difficult to engineer sufficiently long warped throats to prevent decompactification which are also small enough in size to fit into the bulk Calabi-Yau (CY). We give arguments that achieving this with reasonable amount of control may not be possible in generic CY compactifications while CYs with very non-generic geometrical properties might evade our conclusion.Comment: 25 pages, 8 figures, 1 appendix. v2. Note added, references adde

Aspects of F-theory-engineered quantum field theories

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de lectura: 18-09-2018En esta tesis damos de tres ejemplos de teorias cu anticas de campos que pueden ser realizadas en la teor a de supercuerdas IIB, y teor a F. Para empezar, consideramos un modelo modelo de Gran Uni caci on (GUT) de grupo gauge SU(5) en teor a F, con E7 enhancement. Se calculan los acoplos de Yukawa para las dos familias m as pesadas del MSSM, como tambi en una entrada de la matriz CKM. Masas realistas para los fermiones pueden ser encontradas jando algunos valores de los par amentros que entran en el modelo. A continuaci on, consideramos el fen omeno de incremento de supersimetr a en Teor as Cu anticas de Campos (QFTs), en que una teor a con 4 supercargas uye en el IR a una teor a con 8 supercargas. Hacemos nuevas b usquedas sistematicas para encontrar m as teor as que tienen esta propriedad particular. Adem as, damos una explicaci on de este fen omeno a trav es del geometrical engineering de la QFT con una D3 que explora una singularidad en teor a F que corresponde a una con guraci on gauge no-Abeliana conocida como T-brana. Por ultimo, consideramos ramas mixtas de algunas teor as cu anticas de campos 3d N = 4. Damos una manera para calcular la Serie de Hilbert de una cualquier rama mixta para un conjunto dado de teorias, llamadas T[SU(N)]. Para entender como se modi ca la f ormula de la Serie de Hilbert del Coulomb Branch en el caso de un mixed branch, es crucial pensar a la teor a T[SU(N)] en el contexto de la teor a de supercuerdas IIB, a trav es una construcci on de Hanany-Witten.In this thesis we discuss three examples of quantum eld theories engineered from the IIB superstring theory and F-Theory. Firstly we consider a model of SU(5) GUT in F-Theory, with E7 enhancement. Yukawa couplings for the two heaviest families of MSSM are computed, as well as one CKM entry. Realistic masses for the fermions can be obtained by considering certain values of the parameters entering in the model. Secondly, we discuss the phenomenon of supersymmetry enhancement in QFTs, in which a theory with 4 supercharges ows in the IR to a theory with 8 supercharges. New systematic scans are performed in order to nd more theories showing this peculiar feature. Furthermore, an explanation of this SUSY enhancement is given by geometrically engineering the QFT of a D3 probing a F-Theory singularity corresponding to a T-brane background. Thirdly, we consider mixed branches of 3d N = 4 QFTs. We devise a way to compute the Hilbert Series of a generic mixed branch of a particular set of theories of this kind, called T[SU(N)]. In order to understand how the usual formulae for a Coulomb Branch Hilbert series get modi ed in the mixed branch case, it was crucial to engineer the T[SU(N)] in IIB superstring theory, by the use of an Hanany-Witten setu

Implementación de modelos reducidos de cristalizadores batch en SIMULINK

En este TFG se ha desarrollado un simulador de la primera etapa de la sección de cristalización de una factoría azucarera genérica. Para ello se ha desarrollado un modelo reducido de la unidad de proceso más importante en dicha sección: cristalizador discontinuo o por lotes. El modelo de dicha unidad, y de todo el sistema, ha sido programado en SIMULINK, usando la librería STATE-FLOW para la implementación de la “receta” de fabricación de cada lote, y refleja de forma simplificada los caudales de demanda y salida de producto, así como las necesidades de vapor. El simulador se ha validado de forma cualitativa, garantizándose el cumplimiento de los balances de materia. Debe indicarse que el objetivo del simulador es disponer de un predictor que permita a un algoritmo de control determinar la planificación del funcionamiento del sistema completo seleccionando los tiempos de espera entre cada ciclo completo de cada cristalizador.Departamento de Ingeniería de Sistemas y AutomáticaGrado en Ingeniería en Electrónica Industrial y Automátic

Evaluación de variedades de cebada para silaje en 9 de Julio (Bs. As.)

El objetivo del ensayo que se presenta, fue evaluar el comportamiento y producción de materia seca para las condiciones locales de las variedades de cebada Sara INTA, Silera INTA y Huilen INTA, con la finalidad de su utilización en la confección de silos.EEA PergaminoFil: Richmond, Pablo Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Agencia de Extensión Rural 9 de Julio; Argentina.Fil: Carta, Héctor Guillermo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Agencia de Extensión Rural 9 de Julio; Argentina

Five-brane webs, Higgs branches and unitary/orthosymplectic magnetic quivers

We study the Higgs branch of 5d superconformal theories engineered from brane webs with orientifold five-planes. We propose a generalization of the rules to derive magnetic quivers from brane webs pioneered in arXiv:2004.04082, by analyzing theories that can be described with a brane web with and without O5 planes. Our proposed magnetic quivers include novel features, such as hypermultiplets transforming in the fundamental-fundamental representation of two gauge nodes, antisymmetric matter, and $\mathbb{Z}_2$ gauge nodes. We test our results by computing the Coulomb and Higgs branch Hilbert series of the magnetic quivers obtained from the two distinct constructions and find agreement in all cases.Comment: 67 pages, 57 figures, 24 tables, 4 appendices, minor corrections, matches with the published versio