Dieter Hierl

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QPACE is a novel parallel computer which has been developed to be primarily used for lattice QCD simulations. The compute power is provided by the IBM PowerXCell 8i processor, an enhanced version of the Cell processor that is used in the Playstation 3. The QPACE nodes are interconnected by a custom, application optimized 3-dimensional torus network(More)
Application-driven computers for lattice gauge theory simulations have often been based on system-on-chip designs, but the development costs can be prohibitive for academic project budgets. An alternative approach uses compute nodes based on a commercial processor tightly coupled to a custom-designed network processor. Preliminary analysis shows that this(More)
This is a progress report on 2+1 flavor simulation with the FP action on a lattice with spatial size L = 1.2 fm. Since m ud is quite small in our simulation we are in the delta regime for the two light flavors where the low lying excitations are described by a quantum mechanical rotator. From here we extract the low energy constant F. We also measure the(More)
  • P Hasenfratz, D Hierl, V Maillart, F Niedermayer, A Schäfer, C Weiermann +1 other
  • 2009
We generated configurations with the parametrized fixed-point Dirac operator DFP on a (1.6 fm) 4 box at a lattice spacing a = 0.13 fm. We compare the distributions of the three lowest k = 1, 2, 3 eigenvalues in the ν = 0, 1, 2 topological sectors with that of the Random Matrix Theory predictions. The ratios of expectation values of the lowest eigenvalues(More)
Permission to make digital or hard copies of portions of this work for personal or classroom use is granted provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise requires prior specific permission by the publisher mentioned above. In(More)
We study baryons on the lattice with a special focus on excited states. For that purpose we construct several interpolators which differ in their Dirac structure. These interpolators are built from Jacobi smeared quarks with different widths in order to allow for operators with improved spatial wavefunctions. We compute all cross correlations and use the(More)
NQMA-THE-05 Self consistent and covariant propagation of pions, nucleon and isobar resonances 145 in cold nuclear matter NQMA-THE-13 Collective flow of open and hidden charm in the hadron/string picture 153 NQMA-THE-31 The progress and the crisis in the understanding QCD phase diagram 171 Symmetric nuclear matter has been studied extensively. However ,(More)
We report on a study of the pentaquark Θ + (1540), using a variety of different interpolating fields. We use Chirally Improved fermions in combination with Jacobi smeared quark sources to improve the signal and get reliable results even for small quark masses. The results of our quenched calculations, which have been done on a 12 3 × 24 lattice with a(More)
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