Collaborative Research: Innovative ab initio symmetry-adapted no-core shell model for advancing fundamental physics and astrophysics

路易斯安那州立大学的一组研究人员将解决模拟原子核复杂动力学所固有的重大计算挑战，原子核是大量天体物理现象的基础。他们将通过使用蓝色沃茨超级计算机的千万亿次资源来做到这一点。更具体地说，研究人员将对从氧到氩的中等质量原子核进行大规模计算，包括目前和下一代稀有同位素实验设施的重点。这种原子核通常是理解极端环境中的过程的关键，从恒星爆炸到核反应堆内部。该研究项目提供的可靠的核结构信息将对天体物理学和中微子物理学的基础研究问题产生影响，并将在核能等领域具有潜在的应用，从而为国家的能源基础设施做出贡献。 将为下一代物理学家提供利用大规模计算资源的培训，该团队将通过提供前所未有的准确性和范围的核结构信息作为供其他科学家使用的公开数据库来扩大其研究的影响。路易斯安那州立大学团队的方法是求解多体量子系统的薛定谔方程，该系统由质子和中子通过与潜在夸克/胶子考虑相关的现实相互作用相互作用组成。这个问题的解决方案是通过找到核哈密顿量的本征态和本征值来实现的，核哈密顿量是在利用原子核的精确和近似对称性的物理相关基础上计算的。使用这种对称性是我们模型的一个独特功能，与Blue沃茨功能相结合，使解决方案变得可行。也就是说，该团队将采用高度可扩展的计算机代码（称为“LSU 3shell”）实现的适应性强的无核壳模型方法，该方法已经在Blue沃茨系统上表现出良好的可扩展性和性能。计算将提供短寿命缺中子和富中子同位素的核性质，几乎没有可用的实验数据，预计这些数据将对X射线爆发观测数据建模产生相当大的影响，触发负责宇宙中许多重元素合成的过程，并提供对自然界和物理学中基本对称性的严格测试。

A team of researchers at Louisiana State University will address the significant computational challenges inherent to modeling the intricate dynamics of atomic nuclei, which are fundamental to a vast array of astrophysical phenomena. They will do so by employing the petascale resources of the Blue Waters Supercomputer. More specifically, the investigators will carry out large-scale computations of intermediate-mass nuclei from oxygen to argon, including exotic unstable isotopes that are the focus of current and next-generation rare isotope experimental facilities. Such nuclei are often found key to understanding processes in extreme environments, from stellar explosions to the interior of nuclear reactors. Reliable nuclear structure information provided by this research project will have impacts on basic research questions in astrophysics and neutrino physics, and will also have potential applications in areas like nuclear energy, thus contributing to the nation's energy infrastructure. Training in utilizing large-scale computational resources will be provided to, the next generation of physicists, and the team will expand the impact of their research by providing nuclear structure information of unprecedented accuracy and scope as a publicly available database for use by other scientists. The LSU team's approach is to solve the Schrodinger equation for a many-body quantum system composed of protons and neutrons interacting via realistic interactions that are tied to the underlying quark/gluon considerations. The solution to this problem is achieved by finding eigenstates and eigenvalues of the nuclear Hamiltonian, which is computed in a physically relevant basis that capitalizes on exact and approximate symmetries of nuclei. The use of such symmetries is a unique feature of our model, one that coupled with the Blue Waters capabilities makes solutions feasible. Namely, the team will employ the symmetry-adapted no-core shell model approach implemented by a highly scalable computer code, dubbed "LSU3shell", that has already demonstrated good scalability and performance on the Blue Waters system. Calculations will provide nuclear properties of short-lived neutron-deficient and neutron-rich isotopes with little to no available experimental data that are expected to have a considerable impact on modeling X-ray burst observables, on triggering processes responsible for the synthesis of many of the heavy elements present in the universe, and on providing a stringent test of fundamental symmetries in nature and physics beyond the Standard model.