Collaborative Research: Elements: Lattice QCD software for nuclear physics on heterogeneous architectures

核子(质子和中子)组成原子核，是宇宙中所有物质的共同组成部分。为了更好地理解原子核，以及帮助当前的实验发现新的粒子物理和了解被称为中微子的粒子，重要的是对核子不仅与其他核子相互作用，而且与自然界中的其他粒子，如电子、介子和介子相互作用的计算。为了在现代GPU加速的超级计算机系统上进行这类计算的优化软件的开发，可以使用时空格子上涉及夸克场和胶子场的路径积分的蒙特卡罗估计来研究强子-强子相互作用的物理。可以计算重子-介子和重子-重子散射相移，从而获得关于强子结构的重要信息。涉及核子和通过德尔塔重子跃迁的形状因子特别重要，因为它们对基于加速器的中微子实验至关重要，例如地下深中微子实验(DUNE)。新的计算技术，如随机LAPH方法，使得在晶格量子色动力学(LQCD)中进行这样的计算成为可能。在这样的计算中，一个关键但计算密集的因素是对单个重子源和重子汇的评估。这项工作的目标之一是开发高度优化的软件，以评估现代GPU加速架构上的重子源/汇。在这种散射计算的结束阶段需要过多的张量压缩，这在需要不同的墙时间和计算处理器数量的单独的程序执行中执行得最好。在这些计算的工作流程中，有效地将如此众多的运行捆绑到超级计算机系统上的少数批处理作业中是至关重要的。这项工作还将开发软件，以有效地执行这一捆绑。这一奖项由高级网络基础设施办公室联合支持，由数学和物理科学局内物理司的信息前沿物理学计划共同支持。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nucleons (protons and neutrons) make up atomic nuclei and are a common building block of all matter in the universe. To better understand atomic nuclei, as well as to assist current experiments to find new particle physics and to understand particles known as neutrinos, it is important to carry out calculations of nucleons interacting with not only other nucleons but other particles in nature, such as electrons, muons, and mesons. The development of optimized software to carry out such computations on modern GPU-accelerated supercomputer systems is pursued.The physics of hadron-hadron interactions can be studied using Monte Carlo estimates of path integrals involving quark and gluon fields on a space-time lattice. Baryon-meson and baryon-baryon scattering phase shifts can be computed, yielding important information on hadron structure. Form factors involving the nucleon and transitions through the Delta baryon are particularly important since they are crucial to accelerator-based neutrino experiments, such as the Deep Underground Neutrino Experiment (DUNE). New computational techniques, such as the stochastic LapH method, have made possible such computations in lattice quantum chromodynamics (LQCD). A key, but computationally intensive, ingredient in such computations is the evaluation of individual baryon sources and sinks. One goal of this work is the development of highly-optimized software to evaluate baryon sources/sinks on modern GPU-accelerated architectures. A plethora of tensor contractions are needed in the end stages of such scattering calculations, which are best performed in separate program executions requiring different wall times and numbers of computing processors. Effectively bundling such numerous runs together into a handful of batch jobs on supercomputer systems is crucial in the work flow of these computations. This work will also develop the software to efficiently carry out this bundling.This award by the Office of Advanced Cyberinfrastructure is jointly supported by the Physics at the Information Frontier program in the Division of Physics within the Directorate for Mathematical and Physical Sciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.