1,720,989 research outputs found
Bose-Einstein condensation and superfluidity of a weakly interacting photon gas in a nonlinear Fabry-Perot cavity.
No full textA field theoretical framework for the recently proposed photon condensation effect in a nonlinear Fabry-Perot cavity is discussed. The dynamics of the photon gas turns out to be described by an effective 2D Hamiltonian of a complex massive scalar field. Finite size effects turn out to be relevant for the existence of the photon condensate. © 1999 Published by Elsevier Science B.V. All rights reserved
Supersymmetry of the three-dimensional Einstein-Hilbert gravity in the Landau gauge
No full textIn analogy with the Chern-Simons action in the Landau gauge, we find for the 3D Einstein-Hilbert gravity an extra symmetry whose Ward operator, together with the linearized Slavnov operator, gives rise to a N=1 supersymmetric algebra. We discuss furthermore the inclusion in the action either of a cosmological constant or of a topological term which permits the exploitation of the tight analogy of 3D gravity with the Chern-Simons models built on complex gauge groups
Supersymmetric structure of four-dimensional antisymmetric tensor fields
No full textAntisymmetric tensor fields are discussed. The model, as other
topological field theories, possesses a supersymmetric off-shell
structure which can be used to define a class of Slavnov invariant
observables
BRST cohomology of N=2 super-Yang-Mills theory in four dimensions
No full textThe BRST cohomology of the N = 2 supersymmetric Yang-Mills theory in four dimensions is discussed by making use of the twisted version of the N = 2 algebra. By the introduction of a set of suitable constant ghosts associated with the generators of N = 2, the quantization of the model can be done by taking into account both gauge invariance and supersymmetry. In particular, we show how the twisted N = 2 algebra can be used to obtain in a straightforward way the relevant cohomology classes. Moreover, we shall be able to establish a very useful relationship between the local gauge-invariant polynomial tr phi(2) and the complete N = 2 Yang-Mills action. This important relation can be considered as the first step towards a fully algebraic proof of the one-loop exactness of the N = 2 beta-function
The action of N=4 Super Yang-Mills from a chiral primary operator
No full textUsing the Vafa-Witten twisted version of N = 4 super Yang-Mills a subset of the supercharges actually relevant for the non-renormalization properties of the theory is identified. In particular, a relationship between the gauge-fixed action and the chiral primary operator tr phi (2) is worked out. This result can be understood as an off-shell extension of the reduction formula introduced by Intriligator in [1]
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
Perturbative beta function of N=2 super Yang-Mills theories
No full textAn algebraic proof of the nonrenormalization theorem for the perturbative beta function of the coupling constant of N = 2 Super Yang-Mills theory is provided. The proof relies on a fundamental relationship between the N = 2 Yang-Mills action and the local gauge invariant polynomial Tr phi (2), phi (x) being the scalar field of the N = 2 vector gauge multiplet. The nonrenormalization theorem for the beta (g) function follows from the vanishing of the anomalous dimension of Tr phi (2)
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
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