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

这个提议试图理解质子和中子在中子远多于质子的环境中是如何相互作用的，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，它定义了中子滴线，在那里质子和中子不再形成原子核，因为它们不会“粘在一起”（例如，脱离束缚）。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光束设施中进行，该设施估计将在这一感兴趣的地区产生近1000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，由于与量子计算、量子光学和量子传感相关，本课题具有特殊的意义。这项研究的一部分将涉及MoNA合作项目，该项目由一组本科院校组成，这些院校对招收进入核科学领域的学生产生了重大影响。这项研究将进一步开发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族裔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、艺术和数学（STEAM）劳动力，对多样性产生重大影响。本提案旨在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和宇宙天体物理过程相关的核模型。在多信使天文学时代，对连续体效应的正确建模和理解是重要的，在这个时代，核性质，如结合能和核半径与解释光学、中微子和引力波观测相关。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翻一番。非束缚态的性质将使用MoNA协作的强大工具和在FRIB可获得的广泛的新原子核来测量。将开发新技术，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，包括松散束缚系统中近阈值共振的表征。最后，由于感兴趣状态的开量子性质，产生这些状态的反应机制成为测量的重要组成部分。随着专用设备的发展（例如基于切伦科夫和卢瑟福散射的探测器），将探索开放量子系统中反应机制的作用。该项目推进了“宇宙之窗：多信使天体物理学时代”的目标，这是美国国家科学基金会未来投资的十大理念之一。该奖项反映了美国国家科学基金会的法定使命，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.