Publication: D-brane systems and open string compactifications
Authors
Balaguer Tornel, Juan Ramón
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Escuela Internacional de Doctorado
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Fernández Melgarejo, José Juan
Publisher
Universidad de Murcia
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DOI
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info:eu-repo/semantics/doctoralThesis
Description
Abstract
Esta tesis doctoral estudia distintos aspectos de la teoría de cuerdas con especial énfasis en el papel de las D-branas. La motivación general del trabajo se sitúa en el marco del problema abierto de la física teórica de unificar la Relatividad General con la mecánica cuántica, para lo cual la teoría de cuerdas constituye una de las propuestas más consistentes de teoría cuántica de la gravedad. Dentro de este contexto, el objetivo central de la tesis es analizar cómo las D-branas influyen en dos escenarios clave: la holografía y las compactificaciones con flujos.
El trabajo se articula en dos líneas principales. La primera se centra en el estudio de la holografía de precisión mediante la construcción y análisis de nuevas configuraciones de intersección de branas en teoría de cuerdas tipo IIB. Se investigan soluciones de supergravedad asociadas a estos sistemas y se examina su límite de horizonte cercano con el fin de determinar si generan geometrías de tipo Anti de Sitter. Este análisis permite identificar configuraciones explícitas que proporcionan descripciones gravitatorias de teorías de campos de menor dimensión, contribuyendo así a un mejor entendimiento cuantitativo de la correspondencia AdS/CFT, especialmente en situaciones con menor simetría o presencia de defectos.
La segunda línea de investigación aborda las compactificaciones con flujos en presencia de D-branas y planos orientifold, incorporando explícitamente grados de libertad de cuerda abierta. En este marco se estudian reducciones orientifold de la teoría tipo IIB teniendo en cuenta moduli dinámicos asociados a posiciones de branas, grupos gauge no abelianos y flujos. La metodología combina un enfoque top-down, basado en reducciones dimensionales desde teoría de cuerdas, con un enfoque bottom-up apoyado en la clasificación de supergravedades gaugeadas, permitiendo establecer un diccionario entre ambas teorías de forma que los respectivos potenciales escalares coinciden.
Entre los resultados principales destaca, en primer lugar, la identificación de nuevas configuraciones de intersección de branas que generan geometrías AdS3 en el límite de horizonte cercano, proporcionando realizaciones explícitas de ciertas teorías conformes bidimensionales desde teoría de cuerdas. En segundo lugar, se demuestra la coincidencia exacta entre el potencial escalar obtenido a partir de reducciones orientifold de tipo IIB (incluyendo contribuciones tanto del sector de cuerda cerrada como del sector de cuerda abierta) y el potencial derivado de supergravedades gaugeadas con supersimetría N = (1,1) en seis dimensiones. Este resultado confirma la consistencia del marco teórico y establece un vínculo preciso entre construcciones explícitas de teoría de cuerdas y descripciones efectivas de baja energía.
En conjunto, los resultados obtenidos refuerzan el papel central de las D-branas en la estructura de la teoría de cuerdas, tanto en su vertiente holográfica como en la descripción de compactificaciones con flujos.
This thesis studies different aspects of string theory, with special emphasis on the role of D-branes. The general motivation of the work lies within the open problem of theoretical physics of unifying General Relativity with quantum mechanics, for which string theory constitutes one of the most consistent proposals for a quantum theory of gravity. Within this context, the central objective of the thesis is to analyze how D-branes influence two key scenarios: holography and flux compactifications. The work is structured along two main lines. The first focuses on the study of precision holography through the construction and analysis of new intersecting brane configurations in type IIB string theory. Supergravity solutions associated with these systems are investigated, and their near-horizon limit is examined in order to determine whether they generate Anti-de Sitter (AdS) type geometries. This analysis makes it possible to identify explicit configurations that provide gravitational descriptions of lower-dimensional field theories, thereby contributing to a better quantitative understanding of the AdS/CFT correspondence, especially in situations with reduced symmetry or in the presence of defects. The second line of research addresses flux compactifications in the presence of D-branes and orientifold planes, explicitly incorporating open-string degrees of freedom. In this framework, orientifold reductions of type IIB theory are studied while taking into account dynamical moduli associated with brane positions, non-abelian gauge groups, and fluxes. The methodology combines a top-down approach, based on dimensional reductions from string theory, with a bottom-up approach supported by the classification of gauged supergravities, allowing a dictionary to be established between both theories such that their respective scalar potentials coincide. Among the main results, first, the identification of new intersecting brane configurations that generate AdS3 geometries in the near-horizon limit stands out, providing explicit realizations of certain two-dimensional conformal field theories from string theory. Second, the exact agreement is demonstrated between the scalar potential obtained from type IIB orientifold reductions (including contributions from both the closed-string and open-string sectors) and the potential derived from gauged supergravities with N = (1,1) supersymmetry in six dimensions. This result confirms the consistency of the theoretical framework and establishes a precise link between explicit string theory constructions and low-energy effective descriptions. The results obtained reinforce the central role of D-branes in the structure of string theory, both in its holographic aspect and in the description of flux compactifications.
This thesis studies different aspects of string theory, with special emphasis on the role of D-branes. The general motivation of the work lies within the open problem of theoretical physics of unifying General Relativity with quantum mechanics, for which string theory constitutes one of the most consistent proposals for a quantum theory of gravity. Within this context, the central objective of the thesis is to analyze how D-branes influence two key scenarios: holography and flux compactifications. The work is structured along two main lines. The first focuses on the study of precision holography through the construction and analysis of new intersecting brane configurations in type IIB string theory. Supergravity solutions associated with these systems are investigated, and their near-horizon limit is examined in order to determine whether they generate Anti-de Sitter (AdS) type geometries. This analysis makes it possible to identify explicit configurations that provide gravitational descriptions of lower-dimensional field theories, thereby contributing to a better quantitative understanding of the AdS/CFT correspondence, especially in situations with reduced symmetry or in the presence of defects. The second line of research addresses flux compactifications in the presence of D-branes and orientifold planes, explicitly incorporating open-string degrees of freedom. In this framework, orientifold reductions of type IIB theory are studied while taking into account dynamical moduli associated with brane positions, non-abelian gauge groups, and fluxes. The methodology combines a top-down approach, based on dimensional reductions from string theory, with a bottom-up approach supported by the classification of gauged supergravities, allowing a dictionary to be established between both theories such that their respective scalar potentials coincide. Among the main results, first, the identification of new intersecting brane configurations that generate AdS3 geometries in the near-horizon limit stands out, providing explicit realizations of certain two-dimensional conformal field theories from string theory. Second, the exact agreement is demonstrated between the scalar potential obtained from type IIB orientifold reductions (including contributions from both the closed-string and open-string sectors) and the potential derived from gauged supergravities with N = (1,1) supersymmetry in six dimensions. This result confirms the consistency of the theoretical framework and establishes a precise link between explicit string theory constructions and low-energy effective descriptions. The results obtained reinforce the central role of D-branes in the structure of string theory, both in its holographic aspect and in the description of flux compactifications.
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