847 research outputs found
The CP-PACS Project and Lattice QCD Results
The aim of the CP-PACS project was to develop a massively parallel computer
for performing numerical research in computational physics with primary
emphasis on lattice QCD. The CP-PACS computer with a peak speed of 614 GFLOPS
with 2048 processors was completed in September 1996, and has been in full
operation since October 1996. We present an overview of the CP-PACS project and
describe characteristics of the CP-PACS computer. The CP-PACS has been mainly
used for hadron spectroscopy studies in lattice QCD. Main results in lattice
QCD simulations are given.Comment: 10 pages, 5 figures, Talk at the 5th International Conference on
Computational Physics (ICCP5), 11-13 October, 1999, Kanazawa, to appear in
Prog. Theor. Phys. (Suppl.) No. 138 (2000
Quenching Effects in the Hadron Spectrum
Lattice QCD has generated a wealth of data in hadronic physics over the last
two decades. Until relatively recently, most of this information has been
within the "quenched approximation" where virtual quark--anti-quark pairs are
neglected. This review presents a descriptive discussion of the effects of
removing this approximation in the calculation of hadronic masses.Comment: To appear in "Lattice Hadron Physics", ed. A.C. Kalloniatis, D.B.
Leinweber and A.G. William
Thermodynamic properties of QCD with two flavors of Wilson-type lattice quarks
I report on a study of finite temperature QCD by the CP-PACS Collaboration
toward a precise determination of the equation of state with dynamical u,d
quarks. Based on a systematic simulation using improved Wilson-type quarks on
lattices with temporal size and 6, the energy density and pressure are
calculated as functions of temperature and renormalized light quark mass in the
range --2.5 and --0.95. Results
for are found to contain significant scaling violations, while results
for are suggested to be not far from the continuum limit. On the other
hand, the quark mass dependence in the EOS turned out to be small for m_{\rm
PS}/m_{\rm V} \simlt 0.8.Comment: Talk presented at Statistical QCD, Aug. 26-30, 2001, Bielefeld,
Germany. LaTeX2e, 6 pages, 4 PS figures, espcrc1.sty neede
Benchmark Test of CP-PACS for Lattice QCD
The CP-PACS is a massively parallel computer dedicated for calculations in
computational physics and will be in operation in the spring of 1996 at Center
for Computational Physics, University of Tsukuba. In this article, we describe
the architecture of the CP-PACS and report the results of the estimate of the
performance of the CP-PACS for typical lattice QCD calculations.Comment: 12 pages (5 figures), Postscript file, talk presented at "QCD on
Massively Parallel Computers" (Yamagata, Japan, March 16-18,1995
Hadron spectroscopy from lattice QCD
I present recent developments in the lattice QCD calculations of the light
hadron spectrum. Emphasis is placed on the limitation of the quenched
approximation in reproducing the observed spectrum and indications that the
discrepancy is reduced by introducing two flavors of light dynamical quarks.Comment: Talk presented at KEK-Tanashi symposium on "Physics of Hadrons and
Nuclei", 14-17 Dec. 1998, Tokyo, Japan. To be published in Nucl. Phys. A. 8
pages, 10 figure
Computers for Lattice Field Theories
Parallel computers dedicated to lattice field theories are reviewed with
emphasis on the three recent projects, the Teraflops project in the US, the
CP-PACS project in Japan and the 0.5-Teraflops project in the US. Some new
commercial parallel computers are also discussed. Recent development of
semiconductor technologies is briefly surveyed in relation to possible
approaches toward Teraflops computers.Comment: 15 pages with 16 PS figures, review presented at Lattice 93, LaTeX
(espcrc2.sty required
Recent Results from the CP-PACS Collaboration
We present an overview of recent results from the CP-PACS computer on the
quenched light hadron spectrum and an on-going two-flavour full QCD study. We
find that our quenched hadron mass results are compatible with the mass
formulae predicted by quenched chiral perturbation theory, which we adopt in
our final analysis. Quenched hadron masses in the continuum limit show
unambiguous and systematic deviations from experiment. For our two-flavour full
QCD simulation we present preliminary results on the light hadron spectrum,
quark masses and the static potential. The question of dynamical sea quark
effects in these quantities is discussed.Comment: LATTICE98, plenary talk, LaTeX(espcrc2.sty), 13 pages, 23 figure
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