321 research outputs found
Ariel - Volume 6 Number 3
Editors
Mark Dembert
J.D. Kanofsky
Frank Chervenak
John Lammie
Curt Cummings
Staff
Ken Jaffe
Bob Sklaroff
Halley Faust
Jim Burke
Nancy Redfern
Hans Weltin
Photographer
Larry Glazerman
Overseas Editor
Mike Sinason
Humorist
Jim McCan
Temperature and Polarization Patterns in Anisotropic Cosmologies
We study the coherent temperature and polarization patterns produced in
homogeneous but anisotropic cosmological models. We show results for all
Bianchi types with a Friedman-Robertson-Walker limit (i.e. Types I, V,
VII, VII and IX) to illustrate the range of possible behaviour. We
discuss the role of spatial curvature, shear and rotation in the geodesic
equations for each model and establish some basic results concerning the
symmetries of the patterns produced. We also give examples of the
time-evolution of these patterns in terms of the Stokes parameters , and
.Comment: 24 pages, 7 Figures, submitted to JCAP. Revised version: numerous
references added, text rewritten, and errors corrected
From the Dirac Operator to Wess-Zumino Models on Spatial Lattices
We investigate two-dimensional Wess-Zumino models in the continuum and on
spatial lattices in detail. We show that a non-antisymmetric lattice derivative
not only excludes chiral fermions but in addition introduces supersymmetry
breaking lattice artifacts. We study the nonlocal and antisymmetric SLAC
derivative which allows for chiral fermions without doublers and minimizes
those artifacts. The supercharges of the lattice Wess-Zumino models are
obtained by dimensional reduction of Dirac operators in high-dimensional
spaces. The normalizable zero modes of the models with N=1 and N=2
supersymmetry are counted and constructed in the weak- and strong-coupling
limits. Together with known methods from operator theory this gives us complete
control of the zero mode sector of these theories for arbitrary coupling.Comment: 39 pages, 3 figure
Ariel - Volume 6 Number 4 (Alternate Version)
Editors
Mark Dembert
J.D. Kanofsky
Frank Chervenak
John Lammie
Curt Cummings
Entertainment
Robert Breckenridge
Joe Conti
Gary Kaskey
Photographer
Larry Glazerman
Overseas Editor
Mike Sinason
Humorist
Jim McCann
Staff
Kenn Jaffe
Bob Sklaroff
Halley Faust
Jim Burke
Jay Amsterdam
Morton A. Klein
Nancy Redfer
Four-quark stability
The physics of charm has become one of the best laboratories exposing the
limitations of the naive constituent quark model and also giving hints into a
more mature description of meson spectroscopy, beyond the simple
quark--antiquark configurations. In this talk we review some recent studies of
multiquark components in the charm sector and discuss in particular exotic and
non-exotic four-quark systems, both with pairwise and many-body forces.Comment: 6 pages. Article based on the presentations by J. Vijande and J.-M.
Richard at the Fifth Workshop on Critical Stability, Erice, Sicil
Oscillatory behavior of closed isotropic models in second order gravity theory
Homogeneous and isotropic models are studied in the Jordan frame of the
second order gravity theory. The late time evolution of the models is analysed
with the methods of the dynamical systems. The normal form of the dynamical
system has periodic solutions for a large set of initial conditions. This
implies that an initially expanding closed isotropic universe may exhibit
oscillatory behaviour.Comment: 16 pages, 3 figures. With some minor improvements. To appear in
General Relativity and Gravitatio
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