2,187 research outputs found
The Dirac-Dowker Oscillator
The oscillator-like interaction is introduced in the equation for the
particle of arbitrary spin, given by Dirac and re-written to a matrix form by
Dowker.Comment: LaTeX file, 4pp. Preprint EFUAZ 94-0
Radiation from a Charge Uniformly Accelerated for All Time
A recent paper of Singal [Gen. Rel. Grav. 27 (1995), 953-967] argues that a
uniformly accelerated particle does not radiate, in contradiction to the
consensus of the research literature over the past 30 years. This note points
out some questionable aspects of Singal's argument and shows how similar
calculations can lead to the opposite conclusion.Comment: LaTeX, 9 pages, to appear in General Relativity and Gravitatio
Affinities and Beyond! Developing Ways of Seeing in Online Spaces
This article presents an insider view of an online community of adults involved in sharing digital photography through a host website, Flickr. It describes how reciprocal teaching and learning partnerships in a dynamic multimodal environment are achieved through the creation of a ‘Third Space’ or ‘Affinity Space’, where ‘Funds of Knowledge’ are shared and processed in such a way that new meanings and discourses are generated. It is argued that this process is evidence of valuable learning and of the deepening of global understandings within the local space of Flickr. The new understandings are at least partly identifiable on the Flickr space, through the co-constructed ‘folksonomy’ or ‘online taxonomy’ of ways of looking at the world. Further, the article provides evidence for broadening existing definitions of literacy, at a time when the visual mode increasingly works interactively with verbal cues and explanations
Cornelius Lanczos's derivation of the usual action integral of classical electrodynamics
The usual action integral of classical electrodynamics is derived starting
from Lanczos's electrodynamics -- a pure field theory in which charged
particles are identified with singularities of the homogeneous Maxwell's
equations interpreted as a generalization of the Cauchy-Riemann regularity
conditions from complex to biquaternion functions of four complex variables. It
is shown that contrary to the usual theory based on the inhomogeneous Maxwell's
equations, in which charged particles are identified with the sources, there is
no divergence in the self-interaction so that the mass is finite, and that the
only approximation made in the derivation are the usual conditions required for
the internal consistency of classical electrodynamics. Moreover, it is found
that the radius of the boundary surface enclosing a singularity interpreted as
an electron is on the same order as that of the hypothetical "bag" confining
the quarks in a hadron, so that Lanczos's electrodynamics is engaging the
reconsideration of many fundamental concepts related to the nature of
elementary particles.Comment: 16 pages. Final version to be published in "Foundations of Physics
Acting together: ensemble as a democratic process in art and life
Traditionally drama in schools has been seen either as a learning medium with a wide range of curricular uses or as a subject in its own right. This paper argues that the importance of drama in schools is in the processes of social and artistic engagement and experiencing of drama rather than in its outcomes. The paper contrasts the pro-social emphasis in the ensemble model of drama with the pro-technical and limited range of learning in subject-based approaches which foreground technical knowledge of periods, plays, styles and genres. The ensemble-based approach is positioned in the context of professional theatre understandings of ensemble artistry and in the context of revolutionary shifts from the pro-technical to the pro-social in educational and cultural policy making in England. Using ideas drawn from McGrath and Castoriadis, the paper claims that the ensemble approach provides young people with a model of democratic living
Electromagnetic showers in a strong magnetic field
We present the results concerning the main shower characteristics in a strong
magnetic field obtained through shower simulation. The processes of magnetic
bremsstrahlung and pair production were taken into account for values of the
parameter . We compare our simulation results with a recently
developed cascade theory in a strong magnetic field.Comment: 11 pages, 9 eps figures, LaTex2e, Iopart.cls, Iopart12.clo,
Iopams.st
General Solutions of Relativistic Wave Equations II: Arbitrary Spin Chains
A construction of relativistic wave equations on the homogeneous spaces of
the Poincar\'{e} group is given for arbitrary spin chains. Parametrizations of
the field functions and harmonic analysis on the homogeneous spaces are
studied. It is shown that a direct product of Minkowski spacetime and
two-dimensional complex sphere is the most suitable homogeneous space for the
physical applications. The Lagrangian formalism and field equations on the
Poincar\'{e} and Lorentz groups are considered. A boundary value problem for
the relativistically invariant system is defined. General solutions of this
problem are expressed via an expansion in hyperspherical functions defined on
the complex two-sphere.Comment: 56 pages, LaTeX2
Avatars of Eurocentrism in the critique of the liberal peace
Recent scholarly critiques of the so-called liberal peace raise important political and ethical challenges to practices of postwar intervention in the global South. However, their conceptual and analytic approaches have tended to reproduce rather than challenge the intellectual Eurocentrism underpinning the liberal peace. Eurocentric features of the critiques include the methodological bypassing of target subjects in research, the analytic bypassing of subjects through frameworks of governmentality, the assumed ontological split between the ‘liberal’ and the ‘local’, and a nostalgia for the liberal subject and the liberal social contract as alternative bases for politics. These collectively produce a ‘paradox of liberalism’ that sees the liberal peace as oppressive but also the only true source of emancipation. However, the article suggests that a repoliticization of colonial difference offers an alternative ‘decolonizing’ approach to critical analysis through repositioning the analytic gaze. Three alternative research strategies for critical analysis are briefly developed
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