Examinando por Autor "Faraggi, Alberto"
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Ítem Beyond AdS2/dCFT1: insertions in two Wilson loops(Springer Science and Business Media Deutschland GmbH, 2023-10) Correa, Diego H.; Faraggi, Alberto; Mück, Wolfgang; Pando Zayas, Leopoldo A.; Silva, GuillermoWe consider two-point correlators of local operator insertions in a system of two Wilson-Maldacena loops in N = 4 supersymmetric Yang-Mills theory on both sides of the AdS/CFT correspondence. On the holographic side the correlator of two Wilson-Maldacena loops is given by a classical string world-sheet which in one phase connects two asymptotically AdS2 regions and in the other phase is given by two disconnected AdS2 caps; this configuration breaks supersymmetry as well as conformal invariance. We present a complete systematic account of the string world-sheet fluctuations, including the fermionic sector, and study the behavior of the holographic two-point correlators. On the field theory side we compute certain two-point correlators of local operator insertions by resumming sets of ladder diagrams. Our results demonstrate the efficacy of previously developed methods in tackling this non-conformal, non-susy regime. © 2023, The Author(s).Ítem Desarrollo e implementación de métodos de cómputo para densidades de estados, usando ensambles generalizados(Universidad Andrés Bello, 2022) Moreno Muñoz, Felipe Eduardo; Peralta, Joaquín; Davis, Sergio; Faraggi, Alberto; Gutiérrez, Gonzalo; Molina, Francisco; Poblete, Simón; Facultad de Ciencias ExactasEl presente trabajo se enfoca en el desarrollo e implementación de algoritmos de simulación que permitan calcular la Densidad de Estados (DOS) de sistemas de muchas partículas interactuantes usando ensambles generalizados. Métodos para obtener las propiedades de un sistema que se basan en el uso de ensambles canónicos o microcanónicos—como el popular algoritmo de Metropolis—se han usado durante ya un largo tiempo. Sin embargo, el empleo de ensambles generalizados muestra ser una alternativa que permite generar curvas más suaves con menor número de simulaciones, además de evitar ciertos problemas típicos de esos métodos como el tener dificultades para muestrear correctamente sistemas con muchos mínimos locales. En este trabajo se presenta una implementación flexible y modular del algoritmo de Wang–Landau, además de un novedoso algoritmo basado en un método Bayesiano para el cálculo directo de la DOS, los cuales puede ser usados para obtener las propiedades termodinámicas de un sistema con una superficie de energía potencial compleja. Nuestros resultados muestran que los algoritmos son capaces de calcular la DOS con razonable precisión. Hemos estudiado, como aplicación de los métodos anteriormente mencionados, las propiedades termodinámicas de un modelo de Potts de 3 estados modificado, en el contexto de la aproximación de “lattice gas” para partículas cargadas confinadas en un volumen.Ítem First-order Lagrangian of Lovelock gravity and applications(Universidad Andrés Bello, 2022) Guilleminot Arellano, Pablo; Olea, Rodrigo; Merino, Nelson; Faraggi, Alberto; Miskovic, Olivera; Aros, Rodrigo; Corral, Cristóbal; Facultad de Ciencias ExactasEn este trabajo, se analizan, analíticamente, aspectos de evolución espacial en gravedad de Lovelock. Se muestra que la adición de términos de Myers a la acción elimina las derivadas de segundo orden respecto a la variable de evolución. Así, la conexión entre el problema de Dirichlet y Lagrangianos de primer orden es establecida. Luego, se exhibe como la transformada de Legendre de este último permite calcular directamente el Hamiltoniano del sistema para la misma variable de evolución. Con estos resultados, se analiza el comportamiento de cáscaras delgadas con masa en el contexto de gravedad de Lovelock. Para esto, se trabaja el principio variacional escrito en un set adaptado de coordenadas válido cerca de la cáscara. Se concluye que la cantidad que es discontínua en la cáscara es el momentum canónico. Finalmente se obtienen algunas expresiones explicitas para configuraciones con simetría esférica.Ítem Functional determinants of radial operators in AdS 2(Springer Verlag, 2018-06) Aguilera-Damia, Jeremías; Faraggi, Alberto; Zayas, Leopoldo Pando; Rathee, Vimal; Silva, Guillermo A.We study the zeta-function regularization of functional determinants of Laplace and Dirac-type operators in two-dimensional Euclidean AdS2 space. More specifically, we consider the ratio of determinants between an operator in the presence of background fields with circular symmetry and the free operator in which the background fields are absent. By Fourier-transforming the angular dependence, one obtains an infinite number of one-dimensional radial operators, the determinants of which are easy to compute. The summation over modes is then treated with care so as to guarantee that the result coincides with the two-dimensional zeta-function formalism. The method relies on some well-known techniques to compute functional determinants using contour integrals and the construction of the Jost function from scattering theory. Our work generalizes some known results in flat space. The extension to conformal AdS2 geometries is also considered. We provide two examples, one bosonic and one fermionic, borrowed from the spectrum of fluctuations of the holographic 14 -BPS latitude Wilson loop. © 2018, The Author(s).Ítem Interpolating boundary conditions on AdS 2(Springer Science and Business Media Deutschland GmbH, 2023-02) Canazas Garay, Anthonny F.; Correa, Diego H.; Faraggi, Alberto; Silva, Guillermo A.We consider two instances of boundary conditions for massless scalars on AdS2 that interpolate between the Dirichlet and Neumann cases while preserving scale invariance. Assessing invariance under the full SL(2; ℝ) conformal group is not immediate given their non-local nature. To further clarify this issue, we compute holographically 2- and 4-point correlation functions using the aforementioned boundary conditions and study their transformation properties. Concretely, motivated by the dual description of some multi-parametric families of Wilson loops in ABJM theory, we look at the excitations of an open string around an AdS2 ⊂ AdS4 × ℂℙ3 worldsheet, thus obtaining correlators of operators inserted along a 1-dimensional defect in N = 6 super Chern-Simons-matter theory at strong coupling. Of the two types of boundary conditions analyzed, only one leads to the expected functional structure for conformal primaries; the other exhibits covariance under translations and rescalings but not under special conformal transformations. © 2023, The Author(s).Ítem One-loop holography with strings in AdS4 × ℂℙ3(Springer Verlag, 2019-10) David, Marina; Ardón, Rodrigo de León; Faraggi, Alberto; Pando Zayas, Leopoldo A.; Silva, Guillermo A.We compute the one-loop effective action of string configurations embedded in AdS4 × ℂℙ3 which are dual to 16-BPS latitude Wilson Loops in the ABJM theory. To avoid ambiguities in the string path integral we subtract the 12-BPS case. The one-loop determinants are computed by Fourier-decomposing the two dimensional operators and then using the Gel’fand-Yaglom method. We comment on various aspects related to the regularization procedure, showing the cancellation of a hierarchy of divergences. After taking into account an IR anomaly from a change in topology, we find a precise agreement with the field theory result known from supersymmetric localization. © 2019, The Author(s).Ítem Phases of higher spin black holes: Hawking-Page, transitions between black holes, and a critical point(American Physical Society, 2017-09) Bañados, Máximo; Düring, Gustavo; Faraggi, Alberto; Reyes, Ignacio A.We study the thermodynamic phase diagram of three-dimensional sl(N;R) higher spin black holes. By analyzing the semiclassical partition function we uncover a rich structure that includes Hawking-Page transitions to the AdS3 vacuum, first order phase transitions among black hole states, and a second order critical point. Our analysis is explicit for N=4 but we extrapolate some of our conclusions to arbitrary N. In particular, we argue that even N is stable in the ensemble under consideration but odd N is not. © 2017 American Physical Society.