TRR 55:  Hadron Physics from Lattice QCD

• Subject Area: Physics ; Computer Science, Systems and Electrical Engineering ; Mathematics
• Term: from 2008 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 35592816

Quantum Chromodynamics (QCD), i.e. the theory of quarks and gluons and their interactions, is the most complex but also the phenomenologically richest part of the standard model of particle physics. In QCD there exist many open problems, even many related to very fundamental questions. Some of these are: Which novel bound states do exist besides the standard three-quark-states and quark-antiquark states? Which properties do they have? How does the phase diagram of QCD in the temperature-density plane look like? How much orbital angular momentum do quarks carry within the proton? What is the correct low-energy limit of QCD? The members of the Transregional Collaborative Research Centre address these and many other questions in their projects. The Transregional Collaborative Research Centre has three main aims:
(1) Using Lattice-Quantum-Chromodynamics (Lattice QCD) we want to determine quantities, which help to extract from experiments at large accelerator centres detailed information on hadron structure and hadronic reactions.
(2) The close collaboration between physicists and mathematicians is expected to lead to decisive algorithmic progress, allowing for efficient numerical simulations in Lattice QCD, especially for simulations with chiral quarks. (Chiral symmetry plays a crucial role in hadron physics.)
(3) In close collaboration with industry and other research centres and universities we want to develop new specialised parallel computer for Lattice QCD, characterised by a highly competitive price per Tflop and a very low energy consumption.
The central HPC (High Performance Computing) project of the first funding period is called QPACE. In QPACE, enhanced CELL processors (PowerXCell 8i) are connected in a three dimensional torus network by means of programmable network processors (FPGAs). The communication rates thus achieved are so high that one obtains a strongly scalable computing architecture. This project is realised in a large collaboration, primarily with the IBM Research and Development Lab in Böblingen/Germany, and also including the following industrial and academic partners: Forschungszentrum Jülich, DESY, University of Ferrara, University of Milano, Eurotech, Xilinx and Knürr. By the fall of 2009 two large QPACE installations will provide more than 160 TFlops to the members of the Transregional Collaborative Research Centre to realise their projects.

• DFG Programme: CRC/Transregios
• International Connection: Switzerland

Completed projects

• A01 - The QCD phase diagram and the critical point (Project Head Fodor, Zoltan Istvan )
• A02 - QCD thermodynamics at vanishing chemical potential (Project Head Fodor, Zoltan Istvan )
• A03 - Hadron Structure and Generalized Parton Distributions (Project Head Bali, Gunnar )
• A04 - Renormalization of composite operators (Project Heads Braun, Vladimir ;  Göckeler, Meinulf ;  Szabó, Kálmán )
• A05 - The Physics of Charm (Project Heads Collins, Ph.D., Sara ;  Dürr, Stephan )
• A06 - The investigation of hadron resonances (Project Head Göckeler, Meinulf )
• A07 - Strong decays and resonances (Project Head Bali, Gunnar )
• A08 - Chiral perturbation theory for hadron observables (Project Head Schäfer, Andreas )
• A09 - 2+1 flavour QCD in the Epsilon- and Delta-regimes (Project Head Hasenfratz, Peter )
• A10 - Static test charges and string breaking (Project Head Bali, Gunnar )
• A12 - Phenomenological aspects of the QCD crossover region (Project Heads Borsányi, Szabolcs ;  Schäfer, Andreas )
• A13 - Kaon and light quark physics (Project Heads Hölbling, Ph.D., Christian ;  Scholz, Enno E. )
• A14 - Hadron Distribution Amplitudes (Project Head Braun, Vladimir )
• A16 - TMDs and DPDs (Project Head Schäfer, Andreas )
• B01 - Linear solvers and matrix functions (Project Heads Frommer, Andreas ;  Kahl, Karsten )
• B03 - Algorithms for next generation supercomputers (Project Heads Frommer, Andreas ;  Krieg, Stefan ;  Lippert, Thomas )
• B04 - Numerical time integration in HMC computations (Project Head Günther, Michael )
• B05 - Numerical time integration and critical slowing down (Project Heads Günther, Michael ;  Knechtli, Francesco )
• C01 - Development of innovative supercomputer hardware architectures for lattice QCD and similar applications (Project Heads Lippert, Thomas ;  Pleiter, Dirk ;  Wettig, Tilo )
• C02 - Development of system and application software for future supercomputer architectures (Project Heads Bloch, Jacques ;  Frommer, Andreas ;  Solbrig, Stefan )
• Z - Central tasks of the SFB/TRR (Project Head Schäfer, Andreas )

• Applicant Institution: Universität Regensburg
• Co-Applicant Institution: Bergische Universität Wuppertal
• Participating University: Karl-Franzens-Universität Graz
• Participating Institution: Forschungszentrum Jülich
• Spokespersons: Professor Dr. Andreas Frommer, until 6/2016; Professor Dr. Andreas Schäfer, since 7/2016