29,270 research outputs found

    ‘Keeping it real’: the politics of Channel 4's multiculturalism, mainstreaming and mandates

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    This article is a post-print version of the published article which may be viewed at the link below. © The Author 2008. Published by Oxford University Press on behalf of Screen. All rights reserved.When Channel 4 decided how it was going to fill what was described in the Annan Report as ‘the empty room of British broadcasting’, it was agreed that Britain's Africans, Caribbeans and Asians were to be important residents. This was meaningful for Channel 4 because it was tasked with providing what Stephen Lambert then described as ‘opportunities for talents which had previously not been fully served’ and with serving needs ‘which have not been fully defined’. And yet the recent history of the channel has been characterized by the closing stages of a particular kind of ‘public service’ approach; one in which ethnic minorities have become simultaneously integrated in and disconnected from mainstream output in distinct ways. Twenty-five years on, the channel is caught up in the difficulties facing the structuring of public service broadcasting and in the challenges posed by the highly contentious politics of recognition for the settlement of the relation between a variety of social rights. On the one hand, black and Asian Britons, who as part of the postcolonial phase of migration to the UK might be regarded as the ‘old ethnics’, do not now appear to be a priority for Channel 4. On the other, the legacy of the relationship between Channel 4, these communities and broader ideals of ‘multiculturalism’ appears to be strong, not least according to the channel's current claims

    Gauge Transformations, BRST Cohomology and Wigner's Little Group

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    We discuss the (dual-)gauge transformations and BRST cohomology for the two (1 + 1)-dimensional (2D) free Abelian one-form and four (3 + 1)-dimensional (4D) free Abelian 2-form gauge theories by exploiting the (co-)BRST symmetries (and their corresponding generators) for the Lagrangian densities of these theories. For the 4D free 2-form gauge theory, we show that the changes on the antisymmetric polarization tensor e^{\mu\nu} (k) due to (i) the (dual-)gauge transformations corresponding to the internal symmetry group, and (ii) the translation subgroup T(2) of the Wigner's little group, are connected with each-other for the specific relationships among the parameters of these transformation groups. In the language of BRST cohomology defined w.r.t. the conserved and nilpotent (co-)BRST charges, the (dual-)gauge transformed states turn out to be the sum of the original state and the (co-)BRST exact states. We comment on (i) the quasi-topological nature of the 4D free 2-form gauge theory from the degrees of freedom count on e^{\mu\nu} (k), and (ii) the Wigner's little group and the BRST cohomology for the 2D one-form gauge theory {\it vis-{\`a}-vis} our analysis for the 4D 2-form gauge theory.Comment: LaTeX file, 29 pages, misprints in (3.7), (3.8), (3.9), (3.13) and (4.14)corrected and communicated to IJMPA as ``Erratum'

    BRST cohomology and Hodge decomposition theorem in Abelian gauge theory

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    We discuss the Becchi-Rouet-Stora-Tyutin (BRST) cohomology and Hodge decomposition theorem for the two dimensional free U(1) gauge theory. In addition to the usual BRST charge, we derive a local, conserved and nilpotent co(dual)-BRST charge under which the gauge-fixing term remains invariant. We express the Hodge decomposition theorem in terms of these charges and the Laplacian operator. We take a single photon state in the quantum Hilbert space and demonstrate the notion of gauge invariance, no-(anti)ghost theorem, transversality of photon and establish the topological nature of this theory by exploiting the concepts of BRST cohomology and Hodge decomposition theorem. In fact, the topological nature of this theory is encoded in the vanishing of the Laplacian operator when equations of motion are exploited. On the two dimensional compact manifold, we derive two sets of topological invariants with respect to the conserved and nilpotent BRST- and co-BRST charges and express the Lagrangian density of the theory as the sum of terms that are BRST- and co-BRST invariants. Mathematically, this theory captures together some of the key features of both Witten- and Schwarz type of topological field theories.Comment: 20 pages, LaTeX, no figures, Title and text have been changed, Journal reference is given, some references have been adde

    Superfield approach to symmetry invariance in QED with complex scalar fields

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    We show that the Grassmannian independence of the super Lagrangian density, expressed in terms of the superfields defined on a (4, 2)-dimensional supermanifold, is a clear-cut proof for the Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST invariance of the corresoponding four (3 + 1)-dimensional (4D) Lagrangian density that describes the interaction between the U(1) gauge field and the charged complex scalar fields. The above 4D field theoretical model is considered on a (4, 2)-dimensional supermanifold parametrized by the ordinary four spacetime variables x^\mu (with \mu = 0, 1, 2, 3) and a pair of Grassmannian variables \theta and \bar\theta (with \theta^2 = \bar\theta^2 = 0, \theta \bar\theta + \bar\theta \theta = 0). Geometrically, the (anti-)BRST invariance is encoded in the translation of the super Lagrangian density along the Grassmannian directions of the above supermanifold such that the outcome of this shift operation is zero.Comment: LaTeX file, 14 pages, minor changes in the title and text, version to appear in ``Pramana - Journal of Physics'

    A Free N = 2 Supersymmetric System: Novel Symmetries

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    We discuss a set of novel discrete symmetries of a free N = 2 supersymmetric (SUSY) quantum mechanical system which is the limiting case of a widely-studied interacting SUSY model of a charged particle constrained to move on a sphere in the background of a Dirac magnetic monopole. The usual continuous symmetries of this model provide the physical realization of the de Rham cohomological operators of differential geometry. The interplay between the novel discrete symmetries and usual continuous symmetries leads to the physical realization of relationship between the (co-)exterior derivatives of differential geometry. We have also exploited the supervariable approach to derive the nilpotent N = 2 SUSY symmetries of the theory and provided the geometrical origin and interpretation for the nilpotency property. Ultimately, our present study (based on innate symmetries) proves that our free N = 2 SUSY example is a tractable model for the Hodge theory.Comment: LaTeX file, 12 pages, Journal reference is give
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