1,720,958 research outputs found
Wilson loops in ABJM theory reloaded
No full textInternational audienceWe present a new technique for computing supersymmetric Wilson loops in the ABJM theory via supersymmetric localization, valid for arbitrary values of the rank of the gauge group and the Chern-Simons level . The approach relies on an operator representation of the Wilson loops within the Fermi gas formalism in terms of the resolvent of a certain integral operator previously encountered in the computation of the ABJM partition function on the round three-sphere. By deriving a set of nontrivial relations for this resolvent, we obtain exact expressions for the generating functions of Wilson loops in terms of the partition function. For large , these expressions reproduce the weak-coupling expansion of the Wilson loops, and in the large- limit at fixed they match previously obtained high-precision numerical results. This analysis also resolves the longstanding discrepancy between numerical data and the semiclassical expression for the BPS Wilson loop
Tracy-Widom distribution in four-dimensional super-Yang-Mills theories
No full textInternational audienceVarious observables in different four-dimensional superconformal Yang-Mills theories can be computed exactly as Fredholm determinants of truncated Bessel operators. We exploit this relation to determine their dependence on the 't Hooft coupling constant. Unlike the weak coupling expansion, which has a finite radius of convergence, the strong coupling expansion is factorially divergent, necessitating the inclusion of nonperturbative, exponentially small corrections. We develop a method to systematically compute these corrections and discuss the resurgent properties of the resulting transseries
Solving four-dimensional superconformal Yang-Mills theories with Tracy-Widom distribution
Full text linkWe study a special class of observables in and superconformal Yang-Mills theories which, for an arbitrary \u27t Hooft coupling constant , admit representation as determinants of certain semi-infinite matrices. Similar determinants have previously appeared in the study of level-spacing distributions in random matrices and are closely related to the celebrated Tracy-Widom distribution. We exploit this relationship to develop an efficient method for computing the observables in superconformal Yang-Mills theories at both weak and strong coupling. The weak coupling expansion has a finite radius of convergence. The strong coupling expansion involves the sum of the `perturbative\u27 part, given by series in , and the `non-perturbative\u27 part, given by an infinite sum of exponentially small terms, each accompanied by a series in with factorially growing coefficients. We explicitly compute the expansion coefficients of these series and show that they are uniquely determined by the large order behavior of the expansion coefficients of the perturbative part via resurgence relations.39 pages, 3 figure
Tracy-Widom distribution in four-dimensional super-Yang-Mills theories
Full text linkVarious observables in different four-dimensional superconformal Yang-Mills
theories can be computed exactly as Fredholm determinants of truncated Bessel
operators. We exploit this relation to determine their dependence on the 't
Hooft coupling constant. Unlike the weak coupling expansion, which has a finite
radius of convergence, the strong coupling expansion is factorially divergent,
necessitating the inclusion of nonperturbative, exponentially small
corrections. We develop a method to systematically compute these corrections
and discuss the resurgent properties of the resulting transseries.Comment: 6 pages; v2: minor corrections and addition
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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