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

This award supports research 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 quantum systems are coupled to their environments, also referred to as open quantum systems. This research is conducted 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 as well as artificial intelligence and machine learning. A part of the research 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. This award supports 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. It addresses 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. The research team will study various neutron rich isotopes from experiments conducted by the MoNA Collaboration, including halo nuclei, in connection with the wide range of new nuclei accessible at the Facility for Rare Isotope Beams to measure properties of unbound states. By leveraging prior work from the previous awards, the research team will expand the improvement on the understanding of the limits of atomic nuclei. Existing models will be further tested and constrained to describe weakly-bound nuclear systems, a critical step for accurately modeling of astrophysical sites such as neutron stars, supernovae, and compact object mergers that are the sources of multi-messenger astronomy. 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.