ITR - (ASE) - (sim): Optimized Dirac Inverter for Quantum Field Theory

量子场论的大规模数值计算正进入一个新的阶段。这是第一次具有成本效益的专用Terascale硬件提供了模拟核力基本理论的完全非线性的能力，并将实验数据与从头算理论预测相结合。事实上，有一系列来自主要核物理和粒子物理实验室的高精度实验结果，这些结果已经无法用传统模型完全理解。它们需要精确的全量子色动力学（QCD）模拟来解释数据。然而，如果在未来十年内不开发和优化新的或实质性改进的算法，国际格点规范理论倡议的全部潜力将被错过。格点QCD的精确解的主要问题是确定夸克环对物理量影响的有效算法。这种效应在早期的淬火近似中被忽略了，它只处理QCD胶子的效应。为了解决这个问题，我们需要在外部胶子场的存在下计算（狄拉克）夸克传播子的本征值。在这个建议中，我们将做出协调一致的和持续的努力，以寻找新的算法的狄拉克逆变器QCD在不断发展的科学目标的国家格点规范理论倡议和实际的架构正在投入生产的背景下。我们的设计重点是使用最好的物理和经验知识的QCD真空，以指导设计适当的多尺度Krylov空间逆变器，这些逆变器被称为占主导地位的计算密集型内核的所有QCD模拟代码。

Large scale numerical computation for quantum field theory is entering a new phase. For the first time cost effective dedicated Terascale hardware provides the capability to simulate the full non-linearities of the fundamental theory of nuclear forces and to confront experimental data with ab initio theoretical predictions. Indeed there is a range of high precision experimental results coming from the major nuclear and particle physics laboratories that can no longer be fully understood by conventional models. They require accurate full Quantum Chromodynamics (QCD) simulations to interpret the data. However the full potential of the international lattice gauge theory initiative will be missed if new or substantially improved algorithms are not developed and optimized on the multi-Terascale architectures for the next decade. The main problem in getting accurate answers for lattice QCD is an efficient algorithm for determining the effects of quark loops on physical quantities. This effect was ignored in earlier quenched approximations which just treated the effects of the gluons of QCD. To solve this problem one needs to evaluate the eigenvalues of the (Dirac) quark propagator in the presence of external gluon fields. In this proposal we will make a concerted and sustained r effort to find new algorithms for the Dirac inverter for QCD in the context of the evolving scientific objective of the National Lattice Gauge theory initiative and the actual architectures being brought into production. Our design focus is on using the best physical and empirical knowledge of the QCD vacuum to guide the design of appropriate multi-scale Krylov space inverters which are known to dominate the compute intensive kernel of all QCD simulation codes.