239 research outputs found
Staggered domain wall fermions
We construct domain wall fermions with a staggered kernel and investigate
their spectral and chiral properties numerically in the Schwinger model. In
some relevant cases we see an improvement of chirality by more than an order of
magnitude as compared to usual domain wall fermions. Moreover, we present first
results for four-dimensional quantum chromodynamics, where we also observe
significant reductions of chiral symmetry violations for staggered domain wall
fermions.Comment: 7 pages, 4 figures; v2: Added references; Proceedings for the 34th
International Symposium on Lattice Field Theory, University of Southampton,
UK, 24-30 July 201
Lattice fermions with complex mass
We present evidence in the Schwinger model that rooted staggered fermions may
correctly describe the m<0 sector of a theory with an odd number of flavors. We
point out that in QCD-type theories with a complex-valued quark mass every
non-chiral action essentially "borrows" knowledge about the
theta-transformation properties from the overlap action.Comment: 8 pages, 4 figures. v2: eqn. (20) corrected, figs. 3,4 adjusted,
conclusions unchanged. v3: text improved, 2 refs. added (version to appear in
PRD
Physics prospects of UV-filtered overlap quarks
Some key features of the overlap operator with a UV-filtered Wilson kernel
are discussed. The first part concerns spectral properties of the underlying
shifted hermitean Wilson operator and the relation to the observed speedup of
the overlap construction. Next, the localization of the filtered overlap and
its axial-vector renormalization constant are discussed. Finally, results of an
exploratory scaling study for and are presented.Comment: Talk given at Workshop on Computational Hadron Physics, Nicosia,
Cyprus, 14-17 Sep 200
Testing UV-filtered ("fat-link") clover fermions
We investigate filtered clover fermions, built from fat gauge links, both in
one-loop perturbation theory and in numerical simulations. We use a variety of
filtering recipes (APE, HYP, EXP, HEX), some of which are suitable for a HMC
with dynamical fermions. A generic filtering together with a (fat-link) clover
term yields fermions with much reduced chiral symmetry breaking.Comment: 7 pages, Lattice 2006 (Quark Masses, Gauge Couplings, and
Renormalization
Continuum physics with quenched overlap fermions
We calculate , , and in the quenched
continuum limit with UV-filtered overlap fermions. We see rather small scaling
violations on lattices as coarse as and
conjecture that similar advantages would be manifest in unquenched studies.Comment: 10 pages, 5 figures, v2: title changed and other improvements to
match published versio
- …