18,146 research outputs found
Vortices and the SU(3) string tension
We present simulation results comparing the SU(3) heavy quark potential
extracted from the full Wilson loop expectation to that extracted from the
expectation of the Wilson loop fluctuation solely by elements of Z(3). The two
potentials are found to coincide. This agreement is stable under multiple
smoothings of the configurations which remove short distance fluctuations, and
thus reflects long-distance physics. It strongly indicates that the asymptotic
string tension arises from thick center vortices linking with the Wilson loop.Comment: 8 pages, LaTeX file with 6 eps figure
Lattice quark propagator with staggered quarks in Landau and Laplacian gauges
We report on the lattice quark propagator using standard and improved
Staggered quark actions, with the standard, Wilson gauge action. The standard
Kogut-Susskind action has errors of \oa{2} while the ``Asqtad'' action has
\oa{4}, \oag{2}{2} errors. The quark propagator is interesting for studying the
phenomenon of dynamical chiral symmetry breaking and as a test-bed for
improvement. Gauge dependent quantities from lattice simulations may be
affected by Gribov copies. We explore this by studying the quark propagator in
both Landau and Laplacian gauges. Landau and Laplacian gauges are found to
produce very similar results for the quark propagator.Comment: 11 pages, 15 figure
Gluon propagator and zero-momentum modes on the lattice
We investigate the propagators of 4D SU(2) gauge theory in Landau gauge by
Monte Carlo simulations. To be able to compare with perturbative calculations
we use large values. There the breaking of the Z(2) symmetry causes
large effects for all four lattice directions and doing the analysis in the
appropriate state gets important. We find that the gluon propagator in the
weak-coupling limit is strongly affected by zero-momentum modes.Comment: 3 pages, LaTeX, 5 figures, uses espcrc2.sty and epsfig.sty.
Contribution to Lattice'9
Topology and Chiral Symmetry in QCD with Overlap Fermions
We briefly review the overlap formalism for chiral gauge theories, the
overlap Dirac operator for massless fermions and its connection to domain wall
fermions. We describe properties of the overlap Dirac operator, and methods to
implement it numerically. Finally, we give some examples of quenched
calculations of chiral symmetry breaking and topology with overlap fermions.Comment: 12 pages with 6 ps figures; crckapb.sty included; to appear in the
proceedings of the workshop "Lattice Fermions and Structure of the Vacuum",
Oct 5-9, Dubna, Russi
First experiences with HMC for dynamical overlap fermions
We describe an HMC algorithm for dynamical overlap fermions which makes use
of their good chiral properties. We test the algorithm in the Schwinger model.
Topological sectors are readily changed even in the massless case.Comment: 4 pages with 1 ps figure; crckapb.sty included; to appear in the
proceedings of the workshop "Lattice Fermions and Structure of the Vacuum",
Oct 5-9, Dubna, Russi
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