11,897 research outputs found
Noncommutative fermions and Morita equivalence
We study the Morita equivalence for fermion theories on noncommutative
two-tori. For rational values of the parameter (in appropriate units)
we show the equivalence between an abelian noncommutative fermion theory and a
nonabelian theory of twisted fermions on ordinary space. We study the chiral
anomaly and compute the determinant of the Dirac operator in the dual theories
showing that the Morita equivalence also holds at this level.Comment: 12 pages, LaTex file, no figures. Minor corrections, version to
appear in Phys. Lett.
Vortex Softening: Origin of the second peak effect in BiSrCaCuO
Transverse ac permeability measurements in BiSrCaCuO single crystals at low fields and temperatures in a vortex configuration
free of external forces show that the decrease of the critical current as
measured by magnetization loops at the second peak effect is an artifact due to
creep. On the other hand, the increase of critical current at the second peak
is due to a genuine softening of the tilting elastic properties of vortices in
the individual pinning regime that precedes the transition to a disorder state.Comment: 4 pages, 5 figures, RevTex, two column versio
Particle-vortex dynamics in noncommutative space
We study the problem of a charged particle in the presence of a uniform
magnetic field plus a vortex in noncommutative planar space considering the two
possible non-commutative extensions of the corresponding Hamiltonian, namely
the ``fundamental'' and the ``antifundamental'' representations. Using a Fock
space formalism we construct eigenfunctions and eigenvalues finding in each
case half of the states existing in the ordinary space case. In the limit of
we recover the two classes of states found in ordinary space,
relevant for the study of anyon physics.Comment: 13 pages, no figures, plain LaTeX. References adde
Immaterial cultural heritage and a sense of place in film-based art education: A case study of a documentary film project with secondary school children as part of Cine en curso Chile
The following article describes the process of a documentary filmmaking
programme at a secondary school in Chile, which encourages students to engage
with a sense of place and intangible cultural heritage. Run by Gaticine – Centro
de desarrollo social del cine (Centre for the Social Development of Cinema) in
partnership with A Bao A Qu, a non-profit organization based in Barcelona, the
programme assists students in discovering and analysing documentary films from
different times and cultures over the course of a year, while performing practical
filmmaking inside and outside the school. At the end, a short film project is
developed that is premiered in a local cinema. This essay provides a brief overview
of the principles and methodology of the Cinema en curs programme, before
offering a socio-educational consideration of the school in which it was developed
and, finally, an analysis of the project’s delivery
A monopole solution from noncommutative multi-instantons
We extend the relation between instanton and monopole solutions of the
selfduality equations in SU(2) gauge theory to noncommutative space-times.
Using this approach and starting from a noncommutative multi-instanton solution
we construct a U(2) monopole configuration which lives in 3 dimensional
ordinary space. This configuration resembles the Wu-Yang monopole and satisfies
the selfduality (Bogomol'nyi) equations for a U(2) Yang-Mills-Higgs system.Comment: 19 pages; title and abstract changed, brane interpretation corrected.
Version to appear in JHE
Nonlinear Supersymmetry as a Hidden Symmetry
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