1,720,966 research outputs found
Structures Amassées, Orientifolds de Modèles de Dimères et Laminations Supérieures.
No full textCluster algebras and varieties naturally appear in various fields of mathematical physics, such as higher Teichmüller theory and dimer models -- known as brane tilings in the context of string theory.On the first hand, we study the generalisation of Thurston's laminations to higher Teichmüller spaces in the real split case. This guides us towards introducing topological quantum field theories associated with the Iwahori--Hecke algebras of finite Coxeter groups. Those assign a Laurent polynomial with integer coefficients to each punctured surface of finite type.On the other hand, we use dimer models to prove the existence of a stable ultraviolet completion of the dynamical supersymmetry breaking model. Moreover, we derive general results on the existence of gauge anomalies in the worldvolume of D-branes at orientifolds of affine toric Calabi--Yau singularities. Lastly, we provide a physical interpretation of brane tilings on the Klein bottle.Besides, the two preliminary parts of this dissertation are pedogogical invitations first to Fock and Goncharov's higher Teichmüller theory and then to the use of dimer models in string theory and in holography.Les algèbres et variétés amassées se manifestent naturellement dans divers champs de la physique mathématique, comme la théorie de Teichmüller de rang supérieur et l'étude des modèles de dimères. D'une part, on étudie la généralisation des laminations de Thurston aux espaces de Teichmüller de rang supérieur correspondant à des groupes réels déployés. Cela conduit notamment à l'introduction de théories topologiques des champs quantiques liées aux algèbres de Iwahori--Hecke des groupes de Coxeter finis. Celles-là associent un polynôme de Laurent entier à chaque surface épointée de type fini.D'autre part, les modèles de dimères nous permettent de prouver l'existence d'une complétion ultraviolette stable du modèle de brisure dynamique de supersymétrie. On dérive de plus des résultats généraux quant à l'existence d'anomalies de jauge sur des D-branes transverses à des orientifolds de singularités Calabi--Yau affines toriques. Enfin, on donne un sens physique aux modèles de dimères sur la bouteille de Klein.Par ailleurs, les deux parties introductives de ce manuscrit présentent de manière pédagogique la théorie de Teichmüller de rang supérieur de Fock et Goncharov, puis les modèles de dimères en théorie des cordes ainsi que leur emploi dans l'étude des correspondances holographiques
Dimers, Orientifolds and Stability of Supersymmetry Breaking Vacua
Get PDFInternational audienceWe study (orientifolded) toric Calabi-Yau singularities in search for D-brane configurations which lead to dynamical supersymmetry breaking at low energy. By exploiting dimer techniques we are able to determine that while most realizations lead to a Coulomb branch instability, a rather specific construction admits a fully stable supersymmetry breaking vacuum. We describe the geometric structure that a singularity should have in order to host such a construction, and present its simplest example, the Octagon
A short introduction to Monstrous Moonshine
No full textThis paper is an introduction to the Monstrous Moonshine correspondence aiming at an undergraduate level. We review first the classification of finite simple groups and some properties of the monster , and then the theory of classical modular functions and modular forms, in order to define Klein's -invariant. Eventually we turn to the correspondence itself, the historical framework in which it appeared, the ideas that were developped in its proof, and its status nowadays
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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