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Z^d-actions with prescribed topological and ergodic properties
We extend constructions of Hahn-Katznelson and Pavlov to Z^d-actions on
symbolic dynamical spaces with prescribed topological and ergodic properties.
More specifically, we describe a method to build Z^d-actions which are
(totally) minimal, (totally) strictly ergodic and have positive topological
entropy.Comment: 19 pages, 1 figure, referee suggestions incorporated, to appear in
Ergodic Theory and Dynamical System
Investigating and Optimizing the Chiral Properties of Lattice Fermion Actions
We study exceptional modes of both the Wilson and the clover action in order
to understand why quenched clover spectroscopy suffers so severely from
exceptional configurations. We show that, in contrast to the case of the Wilson
action, a large clover coefficient can make the exceptional modes extremely
localized and thus very sensitive to short distance fluctuations. We describe a
way to optimize the chiral behavior of Wilson-type lattice fermion actions by
studying their low energy real eigenmodes. We find a candidate action, the
clover action with fat links with a tuned clover term. We present a calculation
of spectroscopy and matrix elements at Wilson gauge coupling beta=5.7. When
compared to simulations with the standard (nonperturbatively improved) clover
action at small lattice spacing, the action shows good scaling behavior, with
an apparent great reduction in the number of exceptional configurations.Comment: 29 pages, LaTeX with 24 eps figures; Due to the suggestion of a
referee, the previous version of this paper has been merged with
hep-lat/9807002. Otherwise no major change in the contents of either pape
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