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找到新的粒子物理学和理解称为中微子的粒子，重要的是进行核子与其他核子以及自然界中其他粒子（如电子，μ子和介子）相互作用的计算。在现代GPU加速的超级计算机系统上进行这种计算的优化软件的开发正在进行中。强子-强子相互作用的物理学可以使用时空晶格上涉及夸克和胶子场的路径积分的蒙特卡罗估计来研究。重子-介子和重子-重子散射相移可以计算，从而得到关于强子结构的重要信息。涉及核子和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，例如深地下中微子实验（DUNE）。新的计算技术，如随机LapH方法，使这种计算在晶格量子色动力学（LQCD）中成为可能。一个关键的，但计算密集，成分在这样的计算是评估个别重子源和汇。这项工作的一个目标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。在这种散射计算的最后阶段需要过多的张量收缩，这最好在需要不同的壁时间和计算处理器数量的单独程序执行中执行。在超级计算机系统上，将如此多的运行有效地捆绑到少数批处理作业中，对于这些计算的工作流至关重要。这项工作还将开发软件，以有效地执行这种捆绑。高级网络基础设施办公室的这一奖项得到了数学和物理科学理事会物理部信息前沿项目物理学的共同支持。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查进行评估，被认为值得支持的搜索.

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.