RII Track-4:NSF: Exploring the Emergent Features of Exotic Nuclear Systems with First-principles Theory of Nuclear Reactions

Louisiana State University, Baton Rouge LA

Investigators

Abstract

This research project aims to investigate the fundamental properties of the atomic nucleus and its role in the cosmos through first-principles calculations of nuclear reactions. Recent advancements in our understanding of the nuclear force have ushered in an era of first-principles studies focusing on atomic nuclei. However, existing approaches utilizing these advancements for the study of nuclear reactions involving elements heavier than the lightest isotopes still rely on approximations, thereby introducing significant uncertainties. To address this void, the project will leverage state-of-the-art mathematical techniques and computational resources from the most advanced supercomputers in the US. By doing so, it aims to achieve unprecedented levels of accuracy in the description of nuclear reactions. This endeavor is expected to yield highly accurate predictions for systems currently beyond the reach of experimental methodologies, thereby potentially catalyzing breakthroughs in both nuclear science and astrophysics. The project will culminate in the development of a novel computational tool capable of investigating various reaction processes within a unified framework. The anticipated outcomes are poised to exert a significant impact not only in the domain of nuclear physics but also across various fields of astrophysical research as well as in the context of national security. Recent advancements in our comprehension of the nuclear force and high-performance computing, have paved the way for the era of first-principles calculations in nuclear physics. These developments have yielded unprecedentedly accurate results for light nuclei. However, such calculations rapidly become computationally infeasible for systems exceeding a dozen particles, even on the most advanced computing platforms. In this context, it has been demonstrated that reformulating the many-body problem in a new basis—capitalizing on nearly perfect symmetries identified earlier in the history of nuclear physics—can mitigate the combinatorial challenges inherent to first-principles calculations. This innovative approach, the Symmetry-adapted No Core Shell Model has enabled the ab initio description of nuclear structures for systems containing up to 40 particles, achieving a high fidelity to experimental data, particularly for electromagnetic transitions traditionally difficult to grasp in ab initio approaches. Building on this success, the current project aims to extend this theoretical framework to encompass nuclear reactions by utilizing the Resonating Group Method (RGM). In collaboration with Lawrence Livermore National Laboratory, the project seeks to expand the reach of ab initio reaction calculations to study nuclei up to the calcium region. Within the RGM framework, the project will allow a coupled-channel description of reaction process involving various mass partitions and light projectiles from first-principles. The anticipated outcomes hold the promise of impactful applications across multiple domains of astrophysics, as well as significant implications for national security. 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.