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Lattice QCD

Lattice QCD. Stephen J Wallace. Lattice. QCD. Q uantum C hromo D ynamics. Quarks and Gluons  Nuclear force.Nuclear Physics. Missing link!. Broad Scientific Goals. Solve QCD , the theory of quarks and gluons. Explain the masses of particles: n, p,…

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Lattice QCD

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  1. Lattice QCD Stephen J Wallace SURA BOT 11/5/02

  2. Lattice SURA BOT 11/5/02

  3. QCD Quantum ChromoDynamics Quarks and Gluons  Nuclear force.Nuclear Physics Missing link! SURA BOT 11/5/02

  4. Broad Scientific Goals Solve QCD, the theory of quarks and gluons. Explain the masses of particles: n, p,… Explain confinement of quarks and gluons. Develop the connections of nuclear physics to quarks and gluons? SURA BOT 11/5/02

  5. Goals for QCD in Nuclear Physics Explain the masses of particles: p, n, N*, mesons & hybrid mesons. Explain how quarks and gluons make up the spin of the nucleon. Explain charge, magnetism and strangeness distributions of the proton and neutron. Explain the 2-nucleon force because it is the “missing link” to nuclear physics. SURA BOT 11/5/02

  6. Strategies • Solve QCD on a lattice in space & time. • Use high-performance commodity clusters: well-suited to Lattice QCD (Jlab/MIT and FermiLab) • Or use custom chips designed for QCD (QCDOC: Columbia, IBM, Brookhaven Lab). • Focus on hadronic physics outcomes that are important to Nuclear Physics. • Develop software architecture for QCD. SURA BOT 11/5/02

  7. Understand the structure of nucleons Tflop-year First data from CEBAF @12 GeV 102 GPD Measurements at JLAB 101 100 Nucleon GPD’s in Full QCD 10-1 Pion form factor in full QCD 10-2 Quenched nucleon GPD’s Nucleon valence quark momentum agrees with experiment 10-3 10-4 First nucleon structure function calculations 10-5 First numerical simulations 10-6 Lattice gauge theory invented 1974 1990 2000 2010 SURA BOT 11/5/02

  8. Understand Masses of Hybrid Mesons and Confinement Tflop-year First data from CEBAF @12 GeV 10 2 10 1 Exotic candidate at BNL FY06 Clusters 8 Tflop/sec 100 FY03 Clusters 0.5 TFlop/sec Hybrid Decays 10 -1 Full Hybrid Spectrum 10 -2 Quenched Hybrid Spectrum Lattice Spectrum agrees with Experiment for Conventional Mesons. 10 -3 10-4 Flux tubes between Heavy Quarks 10 -5 Hints of a confining potential 10 -6 Lattice gauge theory invented 1974 1990 2000 2010 SURA BOT 11/5/02

  9. Jlab/MIT Collaboration & SURALattice Hadron Physics Collaboration • MIT- Negele, Pochinsky,Dreher • Jlab- Edwards, Richards, Watson • UMd- Ji, Wallace • UVA- Thacker • GWU- Lee • UKy- Liu, Dong, Draper • FIU- Fiebig, Narayanan • Others: Boston, Regina, Caltech, CMU, SURA BOT 11/5/02

  10. Long-Range Plan for Nuclear Science http://www.sc.doe.gov/production/henp/np/nsac/LRP_5547_FINAL.pdf • “Lattice QCD is crucial for answering fundamental questions in strong-interaction physics, and it is widely recognized that definitive lattice QCD calculations require multi-teraflops resources – resources now available at reasonable cost. …. The nuclear science component of an internationally competitive lattice effort requires dedicated facilities providing sustained performance of 0.5 teraflops by 2002, growing to 15 teraflops by 2005.” SURA BOT 11/5/02

  11. Robust Competition & U.S. Response • Japanese have Earth Simulator (25 Tflops sustained) now! • Europeans buying a 5-10 Tflop Lattice machine from IBM/Columbia. • DOE Office of Science has formed national advisory committee for Lattice QCD. • Current Funding under DOE SciDAC Initiative (Scientific Discovery Through Advanced Computation) and for QCDOC. • Ultrascale computing initiative (DOE-SC) SURA BOT 11/5/02

  12. National Lattice QCD Advisory DOE Office of Science • R. Sugar (UCSB) N. Christ (Columbia U.) • J. Negele (MIT) P. Lepage (Cornell U.) • P. MacKenzie (Fermilab) • W. (Chip) Watson (Jlab) • C. Rebbi (Boston U.) • M. Creutz (Brookhaven) • S. Sharpe (U. Washington) SURA BOT 11/5/02

  13. Computer Hardware Planning • 2003: 0.5 Tflop/sec Clusters at Jlab & Fermilab • 2003: 1.5 Tflop/sec QCDOC at Columbia/BNL • 2003: 5 Tflop/sec QCDOC at BNL • 2006: 8 Tflop/sec at BNL, Jlab & Fermilab • 2010: 100 Tflop/sec at ? SURA BOT 11/5/02

  14. Summary • Science-driven computation is recognized widely to be important and timely. • Lattice QCD is a leading science driven application with clear goals and plans. • Experiments + Lattice QCD both are instrumental to achieving science goals of Nuclear Physics. • Ultrascale computing is the way to realize definitive Lattice QCD results. SURA BOT 11/5/02

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