Fiol Núñez, Bartomeu
Overview
Works:  3 works in 5 publications in 2 languages and 5 library holdings 

Roles:  Author 
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Most widely held works by
Bartomeu Fiol Núñez
Probing gauge theories exact results and holographic computations by Blai Garolera Huguet(
Book
)
2 editions published in 2015 in English and held by 2 WorldCat member libraries worldwide
Durant les darreres dues dècades ha aparegut un nou paradigma que permet reformular completament certes teories quàntiques de camps i ens aporta una nova eina que ens permet realitzar càlculs analítics en règims fins ara inaccessibles. Aquest nou paradigma sorgeix del descobriment d'una correspondència o dualitat exacta entre dues teories aparentment molt diferents. Per una banda de la dualitat tenim certes teories quàntiques de camps, com per exemple les denominades teories de YangMills, similars a les teories del Model Estàndard. Aquestes descriuen partícules interactuant en un espai pla ddimensional sense gravetat. A l'altra banda de la dualitat trobem teories que inclouen la gravetat, com ara la Teoria de la Relativitat General d'Einstein o les seves generalitzacions en el marc de la Teoria de Cordes. Aquestes teories de gravetat estan definides sobre espais de dimensió més alta que d, i és per això que aquesta correspondència rep sovint l'adjectiu de "hologràfica". Depenent del context, aquesta rep el nom de dualitat gauge/gravetat, dualitat gauge/corda o AdS/CFT (acrònim anglès per la correspondència particular entre teoria de cordes a espais d'Antide Sitter i teories de camps conformes). Fins ara, una de les correspondències més ben estudiades i que comprenem millor (i sobre la qual es centra la present tesi) és la dualitat entre la teoria quatredimensional N = 4 super YangMills amb grup de gauge SU (N) i teoria de cordes tipus IIB en un espai deudimensional AdS5 × S5 . Aquesta tesi presenta una recopilació de quatre articles publicats en revistes científiques d'alt impacte, tots ells en el camp de la correspondència AdS/CFT i centrats en l'estudi de teories gauge supersimètriques mitjançant la inserció de partícules de prova infinitament massives, seguint trajectòries determinades i transformant sota diverses representacions del grup de gauge. Cadascun d'aquests treballs aporta un pas endavant en el desenvolupament de noves estratègies per calcular correccions més enllà del primer ordre així com en l'ús de resultats exactes accessibles a la Teoria Quàntica de Camps per tal de derivar expressions exactes d'altres observables rellevants de la teoria i realitzar prediccions de Teoria de Cordes
2 editions published in 2015 in English and held by 2 WorldCat member libraries worldwide
Durant les darreres dues dècades ha aparegut un nou paradigma que permet reformular completament certes teories quàntiques de camps i ens aporta una nova eina que ens permet realitzar càlculs analítics en règims fins ara inaccessibles. Aquest nou paradigma sorgeix del descobriment d'una correspondència o dualitat exacta entre dues teories aparentment molt diferents. Per una banda de la dualitat tenim certes teories quàntiques de camps, com per exemple les denominades teories de YangMills, similars a les teories del Model Estàndard. Aquestes descriuen partícules interactuant en un espai pla ddimensional sense gravetat. A l'altra banda de la dualitat trobem teories que inclouen la gravetat, com ara la Teoria de la Relativitat General d'Einstein o les seves generalitzacions en el marc de la Teoria de Cordes. Aquestes teories de gravetat estan definides sobre espais de dimensió més alta que d, i és per això que aquesta correspondència rep sovint l'adjectiu de "hologràfica". Depenent del context, aquesta rep el nom de dualitat gauge/gravetat, dualitat gauge/corda o AdS/CFT (acrònim anglès per la correspondència particular entre teoria de cordes a espais d'Antide Sitter i teories de camps conformes). Fins ara, una de les correspondències més ben estudiades i que comprenem millor (i sobre la qual es centra la present tesi) és la dualitat entre la teoria quatredimensional N = 4 super YangMills amb grup de gauge SU (N) i teoria de cordes tipus IIB en un espai deudimensional AdS5 × S5 . Aquesta tesi presenta una recopilació de quatre articles publicats en revistes científiques d'alt impacte, tots ells en el camp de la correspondència AdS/CFT i centrats en l'estudi de teories gauge supersimètriques mitjançant la inserció de partícules de prova infinitament massives, seguint trajectòries determinades i transformant sota diverses representacions del grup de gauge. Cadascun d'aquests treballs aporta un pas endavant en el desenvolupament de noves estratègies per calcular correccions més enllà del primer ordre així com en l'ús de resultats exactes accessibles a la Teoria Quàntica de Camps per tal de derivar expressions exactes d'altres observables rellevants de la teoria i realitzar prediccions de Teoria de Cordes
New insights into holography from supersymmetric localization by Genís Torrents Verdaguer(
Book
)
2 editions published in 2016 in English and held by 2 WorldCat member libraries worldwide
Maldacena's conjecture, often known as the holographic duality or the AdS/CFT correspondence, proposes an equivalence between gravitational theories in a hyperbolic space of a certain dimensionality and gauge theories living on its boundary. The manner in which this connection is established makes the duality specially remarkable: both sides are thought to describe the very same string theoretic physics, but the validity regimes of the two descriptions are disjoint, and one expects either framework to be in its regime of validity the appropriate way to effectively reexpress the physics of the other. The nonintersection of these applicability regimes makes the duality very useful, but also very hard to verify and materialize. Notice the potential implications of this framework for theoretical physics: one direction, strongly coupled quantum field theories become in a certain regime describable as semiclassical gravitational spacetimes, while on the other direction certain string theories without semiclassical background obtain a clean and workable definition as gauge field theories. As a consequence of these facts, holography has played a central role in research since its appearance, almost two decades ago. However, despite numerous efforts devoted to its characterization, general understanding of the duality has only been majoritarely achieved around the regimes where the gravitational description becomes semiclassical. Consequently, the gaugetogravity direction of the duality is far less exploited than the opposite one, despite its conceptual relevance. Having available results for strongly coupled gauge theories would be of a great help in addressing holography in this comparatively underdevelopped direction, and they would set a fertile ground to test, refine and understand the holographic conjecture. These type of predictions are hard to come by, but not inexistent: nonrenormalized magnitudes constitute their most paradygmatical example, and recently different techniques have obtained exact results at arbitrary coupling for specific obserable sectors. This thesis studies specifically one of these techniques, known as supersymmetric localization, and its role in shoring AdS/CFT. In particular, it restricts its analysis to a specific type of theory: Lagrangian N. = 2 SYM, and for specific results: halfBPS Wilson circular loops. Several interesting insights are put forward by its results. A first observation is that the exact functional dependence we obtain from localization offer a guide on how to extend holographic predictions from their validity regime to a finite gauge range which produces plausible results, although a great care has to be taken in this process. Complementarily, the study of this parametrical dependence for gauge N. = 4 theories with gauge Lie algebras presents two suggestive patterns: On the one hand, 't Hooft's topological expansion presents, at least for charges in fundamental representations, an underlying structure that relates sectors with different number of crosscaps among themselves. On the other hand, the matrix model structure obtained in the localization process can be interpreted in terms of a fermionic quantum mechanics, which at the 't Hooft limit matches the "bubbling geometry" structure of Lin, Lunin and Maldacena, but which persists at finite gauge group range. Finally, the comparison of localization results within a more general type of construction is presented. The specific set of theories considered contains both examples with semiclassical holographic duals and examples where this type of geometry is precluded. Supersymmetric field predictions in this case differentiate both groups with qualitatively different behaviours in the matrix model. This suggests a possible connection between the matrix model structure and the semiclassical spacetime codification in the dual field theory. Similar observations have been made in the literature. This thesis, therefore, explicits a wide list of suggestions for holography that are motivated by localization results in different regimes, even though the latter have been severely restricted to particular examples
2 editions published in 2016 in English and held by 2 WorldCat member libraries worldwide
Maldacena's conjecture, often known as the holographic duality or the AdS/CFT correspondence, proposes an equivalence between gravitational theories in a hyperbolic space of a certain dimensionality and gauge theories living on its boundary. The manner in which this connection is established makes the duality specially remarkable: both sides are thought to describe the very same string theoretic physics, but the validity regimes of the two descriptions are disjoint, and one expects either framework to be in its regime of validity the appropriate way to effectively reexpress the physics of the other. The nonintersection of these applicability regimes makes the duality very useful, but also very hard to verify and materialize. Notice the potential implications of this framework for theoretical physics: one direction, strongly coupled quantum field theories become in a certain regime describable as semiclassical gravitational spacetimes, while on the other direction certain string theories without semiclassical background obtain a clean and workable definition as gauge field theories. As a consequence of these facts, holography has played a central role in research since its appearance, almost two decades ago. However, despite numerous efforts devoted to its characterization, general understanding of the duality has only been majoritarely achieved around the regimes where the gravitational description becomes semiclassical. Consequently, the gaugetogravity direction of the duality is far less exploited than the opposite one, despite its conceptual relevance. Having available results for strongly coupled gauge theories would be of a great help in addressing holography in this comparatively underdevelopped direction, and they would set a fertile ground to test, refine and understand the holographic conjecture. These type of predictions are hard to come by, but not inexistent: nonrenormalized magnitudes constitute their most paradygmatical example, and recently different techniques have obtained exact results at arbitrary coupling for specific obserable sectors. This thesis studies specifically one of these techniques, known as supersymmetric localization, and its role in shoring AdS/CFT. In particular, it restricts its analysis to a specific type of theory: Lagrangian N. = 2 SYM, and for specific results: halfBPS Wilson circular loops. Several interesting insights are put forward by its results. A first observation is that the exact functional dependence we obtain from localization offer a guide on how to extend holographic predictions from their validity regime to a finite gauge range which produces plausible results, although a great care has to be taken in this process. Complementarily, the study of this parametrical dependence for gauge N. = 4 theories with gauge Lie algebras presents two suggestive patterns: On the one hand, 't Hooft's topological expansion presents, at least for charges in fundamental representations, an underlying structure that relates sectors with different number of crosscaps among themselves. On the other hand, the matrix model structure obtained in the localization process can be interpreted in terms of a fermionic quantum mechanics, which at the 't Hooft limit matches the "bubbling geometry" structure of Lin, Lunin and Maldacena, but which persists at finite gauge group range. Finally, the comparison of localization results within a more general type of construction is presented. The specific set of theories considered contains both examples with semiclassical holographic duals and examples where this type of geometry is precluded. Supersymmetric field predictions in this case differentiate both groups with qualitatively different behaviours in the matrix model. This suggests a possible connection between the matrix model structure and the semiclassical spacetime codification in the dual field theory. Similar observations have been made in the literature. This thesis, therefore, explicits a wide list of suggestions for holography that are motivated by localization results in different regimes, even though the latter have been severely restricted to particular examples
Estimació teòrica de la raó d'embrancament semileptònica dels mesons B : memòria presentada ... com a treball de recerca
de tercer cicle de doctorat en Física de Partícules i Gravitació by
Bartomeu Fiol Núñez(
)
1 edition published in 1995 in Catalan and held by 1 WorldCat member library worldwide
1 edition published in 1995 in Catalan and held by 1 WorldCat member library worldwide
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