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

该提案旨在了解质子和中子如何相互作用，当它们被放置在中子远多于质子的环境中时，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，在那里质子和中子不再形成原子核，因为它们不“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中进行，主要是在密歇根州的稀有同位素束设施中进行，该设施估计将在这一感兴趣的地区生产近1 000种新同位素。这些同位素的结构和性质与理解天体物理过程高度相关。此外，由于它与量子计算、量子光学和量子传感的相关性，该主题具有特殊的意义。将进行的研究的一部分涉及莫纳协作，该协作由一组对学生进入核科学产生重大影响的本科院校组成。该研究将进一步开发LISE++代码，该代码被世界各地数千名科学家用于稀有同位素生产的建模。这项工作将通过少数民族服务机构参与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，艺术与数学（STEAM）这项提议是对弱束缚原子核进行实验研究，以测试与理解开放量子系统有关的核模型，宇宙中的天体物理过程。在多信使天文学的时代，正确的建模和理解连续效应是很重要的，在这个时代，核的性质，如结合能和核半径，与解释光学，中微子和引力波观测有关。它将解决一些基本问题，比如中子和质子的什么组合可以形成原子核，也许还能使我们对中子滴线的了解增加一倍。将使用莫纳协作的强大工具和FRIB可访问的各种新核来测量未结合态的性质。将开发新技术，利用准弹性质子去除反应探测粒子发射阈值附近的状态和弱束缚核的结构，包括松散束缚系统中阈值附近共振的特性。最后，由于感兴趣的状态的开放量子性质，产生这些状态的反应机制成为测量的重要部分。反应机制在开放量子系统中的作用将随着专用设备的开发而探索（例如，该项目推进了“宇宙之窗：多信使天体物理学时代”的目标，这是NSF未来投资的10大创意之一。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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.