3 research outputs found
FLIC-Overlap Fermions and Topology
APE smearing the links in the irrelevant operators of clover fermions
(Fat-Link Irrelevant Clover (FLIC) fermions) provides significant improvement
in the condition number of the Hermitian-Dirac operator and gives rise to a
factor of two savings in computing the overlap operator. This report
investigates the effects of using a highly-improved definition of the lattice
field-strength tensor F_mu_nu in the fermion action, made possible through the
use of APE-smeared fat links in the construction of the irrelevant operators.
Spurious double-zero crossings in the spectral flow of the Hermitian-Wilson
Dirac operator associated with lattice artifacts at the scale of the lattice
spacing are removed with FLIC fermions composed with an O(a^4)-improved lattice
field strength tensor. Hence, FLIC-Overlap fermions provide an additional
benefit to the overlap formalism: a correct realization of topology in the
fermion sector on the lattice.Comment: Lattice2002(chiral
Dynamical fat link fermions
The use of APE smearing or other blocking techniques in fermion actions can
provide many advantages. There are many variants of these fat link actions in
lattice QCD currently, such as FLIC fermions. Frequently, fat link actions make
use of the APE blocking technique in combination with a projection of the
blocked links back into the special unitary group. This reunitarisation is
often performed using an iterative maximisation of a gauge invariant measure.
This technique is not differentiable with respect to the gauge field and thus
prevents the use of standard Hybrid Monte Carlo simulation algorithms. The use
of an alternative projection technique circumvents this difficulty and allows
the simulation of dynamical fat link fermions with standard HMC and its
variants.Comment: LHP '03 (Cairns) Proceeding
Baryon Spectroscopy in Lattice QCD
We review recent developments in the study of excited baryon spectroscopy in
lattice QCD. After introducing the basic methods used to extract masses from
correlation functions, we discuss various interpolating fields and lattice
actions commonly used in the literature. We present a survey of results of
recent calculations of excited baryons in quenched QCD, and outline possible
future directions in the study of baryon spectra.Comment: Contribution to Lecture Notes in Physics on Lattice Hadron Physics,
43 pages, 11 figures, 3 table