1,720,955 research outputs found
Condizioni al bordo di teorie di gauge N=2 tetradimensionali
No full textIn questa tesi esploriamo la dinamica delle teorie di gauge supersimmetriche 4d N=2 in presenza di bordo, con 1/2-BPS condizioni al bordo, in diversi scenari. Lo facciamo con l'obiettivo di migliorare strumenti analitici per modelli progressivamente meno vincolati e per migliorare la nostra comprensione della dinamica introdotta dai bordi in teorie quantistiche di campo oltre il regime perturbativo. Intendiamo anche far progredire la conoscenza dello spazio consentito delle condizioni al contorno in funzione dei parametri di una teoria e della scala energetica. Un' importante classe di modelli che abbiamo preso in considerazione sono le teorie di campo conformi con bordo, che possono essere realizzate in natura in transizioni di fase di secondo ordine per sistemi racchiusi in regioni finite. In questo contesto abbiamo studiato come calcolare esattamente la funzione a un punto degli operatori chirali 4d N=2 mediante localizzazione supersimmetrica, collegando questi calcoli alle derivate della funzione di partizione dell'emisfero e del suo coniugato. Abbiamo anche avviato uno studio teorico delle stringhe, tramite costruzioni di brane, che realizzano queste teorie di campo. Ciò ci consente di discutere le dualità tra regimi debolmente e fortemente accoppiati. Come ulteriore applicazione della nostra comprensione delle teorie di gauge supersimmetriche con confini, avviamo uno studio di teorie N=2 asintoticamente libere in AdS4. In questa configurazione, la scala di curvatura svolge il ruolo di un regolatore IR che consente di interpolare tra il regime UV debolmente accoppiato e quello IR fortemente accoppiato. Grazie alla supersimmetria siamo in grado di ottenere nuovi risultati esatti che utilizziamo per studiare le condizioni al contorno disponibili e il loro comportamento quando modifichiamo il raggio di AdS. In particolare ci concentriamo sullo studio di quando le condizioni al contorno di Dirichlet, possibili solo quando esistono stati asintotici colorati, si destabilizzano, segnalando così la fine della fase deconfinata.In this thesis we explore the dynamics of 4d N=2 supersymmetric gauge theories in presence of a boundary, with 1/2-BPS boundary conditions, in different scenarios. We do this with the aim of enlarging the scopes of analytical tools, for progressively less constrained models, and for improving our comprehension of the dynamics of boundaries in quantum field theory beyond the perturbative regime. We also intend to advance the knowledge of the allowed space of boundary conditions in function of the parameters of a theory and the energy scale. An important class of models we considered are boundary Conformal Field Theories, which can be realized in nature at second order phase transition for a system enclosed in a finite region. Within this context we studied how to exactly compute the one-point function of 4d N=2 chiral operators by means of supersymmetric localization, relating these computations to derivatives of the hemisphere partition function and its conjugate. We also initiate a string theoretic study of brane constructions realizing these field theoretic systems. This allows us to argue dualities among weakly and strongly coupled regimes. As a further application of our understanding of supersymmetric gauge theories with boundaries, we initiate a study of asymptotically free N=2 theories in AdS4. In this set up, the curvature scale plays the role of an IR regulator which allows to interpolate between the weakly coupled UV regime and the strongly coupled IR one. Thanks to supersymmetry we are able to obtain novel exact results that we use to study the available boundary conditions and their behaviour as we change the AdS radius. In particular we focus on studying when Dirichlet boundary conditions, possible only when colored asymptotic states exists, destabilize, thus signalling the end of the deconfined phase
BCFT One-point Functions of Coulomb Branch Operators
Get PDFAbstract We show that supersymmetry can be used to compute the BCFT one-point function coefficients for chiral primary operators, in 4d N = 2 SCFTs with 1 2 -BPS boundary conditions. The main ingredient is the hemisphere partition function, with the boundary condition on the equatorial S 3. A supersymmetric Ward identity relates derivatives with respect to the chiral coupling constants to the insertion of the primaries at the pole of the hemisphere. Exact results for the one-point functions can be then obtained in terms of the localization matrix model. We discuss in detail the example of the super Maxwell theory in the bulk, interacting with 3d N = 2 SCFTs on the boundary. In particular we derive the action of the SL(2,ℤ) duality on the one-point functions
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
