Computing quark propagation in a gluon background

计算胶子背景中的夸克传播

• 批准号: 469264402
• 负责人: Professor Dr. Andreas Frommer
• 金额: --
• 依托单位: Arbeitsgruppe Angewandte Informatik
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/469264402?language=en
• 关键词: Computing; quark; propagation; gluon; background

We develop, analyze and implement improved and novel methods from numerical linear algebra for those tasks in the Lattice QCD simulation which are computation bound. We contribute state-of-the-art simulation technology, enabling the physics program of this Research Unit to be pursued efficiently and with the required accuracy.Our first major objective is to further exploit hierarchical concepts to solve systems involving the Wilson-Dirac matrix. In particular, we consider the extension of hierarchical methods to the distillation approach and will use this to obtain particularly efficient solvers for the special situations where linear solvers are needed for the computation of eigenpairs. This is particularly relevant for the spectroscopy calculations of charmonium. In addition, we will consider improvements for the setup phase in the adaptive algebraic multigrid methods and novel approaches to efficiently solve the coarsest grid systems in parallel. These improvements will speed-up spectroscopy calculations involving quark propagators and can be used in HMC integration methods.Our second major objective is to provide efficient methods for the computation of disconnected contributions, i.e. of the traces of the inverse of (modifications of) the Wilson-Dirac matrix on a given time slice. We will investigate how the multilevel Monte-Carlo principle can be exploited here to reduce the variance in stochastic estimators in a volume-independent manner, as opposed to current deflation approaches. We will further combine the multilevel Monte-Carlo approach with probing techniques to obtain further improvements. The computation of disconnected contributions represents one of the milestones of this Research Unit.

我们从数值线性代数中开发、分析和实现了改进的、新颖的方法来解决晶格QCD仿真中那些计算受限的任务。我们提供最先进的模拟技术，使该研究单位的物理程序能够有效地进行，并具有所需的准确性。我们的第一个主要目标是进一步利用层次概念来解决涉及威尔逊-狄拉克矩阵的系统。特别地，我们考虑了分层方法对蒸馏方法的扩展，并将使用它来获得特别有效的解算器，用于需要线性解算器来计算特征对的特殊情况。这对charmonium的光谱计算尤其重要。此外，我们将考虑自适应代数多重网格方法中设置阶段的改进以及有效并行求解最粗网格系统的新方法。这些改进将加速涉及夸克传播子的光谱学计算，并可用于HMC积分方法。我们的第二个主要目标是提供有效的方法来计算不相关的贡献，即在给定的时间片上计算Wilson-Dirac矩阵的逆（修改）的轨迹。我们将研究如何在这里利用多层蒙特卡罗原理以体积无关的方式减少随机估计量的方差，而不是目前的紧缩方法。我们将进一步将多层蒙特卡罗方法与探测技术相结合，以获得进一步的改进。不相关捐款的计算是本研究股的一个里程碑。