5,715 research outputs found
Supersymmetry of the magnetic vortex
The N=2 supersymmetry of the Pauli Hamiltonian in any static magnetic field
in the plane combines, for the magnetic vortex, with Jackiw's bosonic
symmetry, into an dynamical
supersymmetry.Comment: 4 pages. Originally Tours Preprint no 60/93 (1993). Unpublishe
Chiral fermions as classical massless spinning particles
Semiclassical chiral fermion models with Berry term are studied in a
symplectic framework. In the free case, the system can be obtained from
Souriau's model for a relativistic massless spinning particle by "enslaving"
the spin. The Berry term is identified with the classical spin two-form of the
latter model. The Souriau model carries a natural Poincar\'e symmetry that we
highlight, but spin enslavement breaks the boost symmetry. However the relation
between the models allows us to derive a Poincare symmetry of unconventional
form for chiral fermions. Then we couple our system to an external
electromagnetic field. For gyromagnetic ratio we get curious superluminal
Hall-type motions; for and in a pure constant magnetic field in
particular, we find instead spiraling motions.Comment: Substantially revised and extended version. 31 pages, 5 figures.
Details clarified and references added. To be published in PR
On Schr\"odinger superalgebras
We construct, using the supersymplectic framework of Berezin, Kostant and
others, two types of supersymmetric extensions of the Schr\"odinger algebra
(itself a conformal extension of the Galilei algebra). An `-type' extension
exists in any space dimension, and for any pair of integers and . It
yields an superalgebra, which generalizes the N=1 supersymmetry
Gauntlett et al. found for a free spin-\half particle, as well as the N=2
supersymmetry of the fermionic oscillator found by Beckers et al. In two space
dimensions, new, `exotic' or `-type' extensions arise for each pair of
integers and , yielding an superalgebra of
the type discovered recently by Leblanc et al. in non relativistic Chern-Simons
theory. For the magnetic monopole the symmetry reduces to
\o(3)\times\osp(1/1), and for the magnetic vortex it reduces to
\o(2)\times\osp(1/2).Comment: On Schr\"odinger superalgebras, no figurs. Published versio
Strings in plane-fronted gravitational waves
Brinkmann's plane-fronted gravitational waves with parallel rays --~shortly
pp-waves~-- are shown to provide, under suitable conditions, exact string vacua
at all orders of the sigma-model perturbation expansion.Comment: 7 pages, no figure
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