Windows on the Universe: Open Quantum Systems in Atomic Nuclei at FRIB

这一提议旨在了解质子和中子在中子远远多于质子的环境中是如何相互作用的，质子也被称为稀有同位素。这些富含中子的稀有同位素跨越了存在的极限，这定义了中子滴线，在这条线上，质子和中子不再形成原子核，因为它们不会“粘在一起”(例如，变得不受约束)。它们提供了一个探索与自身相互作用的系统的独特科学的机会，也被称为开放量子系统。这项研究将在世界各地的科学用户设施进行，主要是在密歇根州的稀有同位素束设施进行，据估计，该设施将在这一感兴趣的地区生产近1000种新的同位素。这些同位素的结构和性质与理解天体物理过程密切相关。此外，由于这个主题与量子计算、量子光学和量子传感相关，因此具有特殊的意义。将进行的研究的一部分涉及MONA合作，该合作由一组本科机构组成，对核科学学生的招生产生了重大影响。这项研究将进一步开发世界各地数千名科学家用来模拟稀有同位素生产的LISE++代码。这项工作将对多样性产生重大影响，因为少数族裔服务机构参与了拟议的研究，以及大学预科学生参与培训下一代科学、技术、工程、艺术和数学(STEAM)工作人员。这项提议是对弱束缚原子核进行实验研究，以测试与理解宇宙中开放量子系统和天体物理过程相关的核模型。在多信使天文学时代，对连续谱效应的适当建模和理解是重要的，在这个时代，核属性，如结合能和核半径，对于解释光学、中微子和引力波观测是相关的。它将解决基本问题，如中子和质子的什么组合可以形成原子核，并可能使我们对中子滴线的了解增加一倍。非束缚态的性质将使用MONA合作的强大工具和在FRIB上可以访问的广泛的新原子核来测量。将开发新的技术来利用准弹性质子去除反应来探测粒子发射阈值附近的状态和弱束缚核的结构，包括表征松散束缚系统中的近阈值共振。最后，由于感兴趣态的开放量子性质，产生这些态的反应机制成为测量的重要部分。将通过开发专用设备(例如，基于切伦科夫和卢瑟福散射的探测器)来探索开放量子系统中反应机制的作用。该项目推进了未来NSF投资的十大想法之一的“宇宙之窗：多信使天体物理时代”的目标。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。

This proposal seeks to understand how protons and neutrons interact when they are placed in an environment where there are far more neutrons than protons, also known as rare isotopes. These neutron-rich rare isotopes straddle the limit of existence, which defines the neutron drip line, where protons and neutrons no longer form a nucleus because they do not “stick” together (e.g., become unbound). They offer an opportunity to explore the unique science of systems that interact with themselves, also referred to as open quantum systems. This research will be conducted at worldwide scientific user facilities, and primarily at the Facility for Rare Isotope Beams in Michigan that is estimated to produce nearly 1,000 new isotopes in this region of interest. The structure and properties of these isotopes are highly relevant for understanding astrophysical processes. In addition, this topic has special significance due to its relevance to quantum computing, quantum optics, and quantum sensing. A part of the research that will be performed involves the MoNA Collaboration, which consists of a group of undergraduate institutions that has had a major impact on recruitment of students to enter nuclear science. The research will further develop the LISE++ code that is used by thousands of scientists around the world for the modeling of rare isotope production. The work will have a significant impact on diversity by involvement of Minority Serving Institutions in the proposed research as well as the involvement of pre-college students to train the next generation of the science, technology, engineering, art and mathematics (STEAM) workforce.This proposal is to perform experimental studies of weakly bound atomic nuclei in order to test nuclear models that are relevant to understanding open quantum systems and astrophysical processes in the universe. Proper modeling and understanding of continuum effects are important in the era of multi-messenger astronomy where nuclear properties, such as binding energies and nuclear radii are relevant for interpreting optical, neutrino, and gravitational-wave observations. It will address fundamental questions, such as what combination of neutrons and protons can form an atomic nucleus and perhaps double our knowledge of the neutron drip line. Properties of unbound states will be measured using the powerful tools of the MoNA Collaboration and the wide range of new nuclei accessible at FRIB. New techniques will be developed to exploit quasi-elastic proton removal reactions to probe states near the particle emission threshold and the structure of weakly-bound nuclei, including the characterization of near threshold resonances in loosely bound systems. Finally, due to the open-quantum nature of the states of interest, the reaction mechanism to produce these states becomes an important part of the measurement. The role of the reaction mechanism in the context of open quantum systems will be explored with the development of dedicated equipment (e.g., Cherenkov and Rutherford scattering based detectors).This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.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.