Toward A Spectroscopically Accurate Nuclear Structure Theory: Exploring Strongly Correlated Media via Spectral Observables

About This Grant

Nuclear structure theory plays a key role at the cutting edge of science and underlies many frontiers of fundamental physics. The detailed knowledge of nuclear spectral properties is essential for multimessenger astrophysics, the search for new physics beyond the Standard Model, and numerous applications of nuclear data and technologies. However, despite decades-long efforts, the theory struggles with intellectual and computational challenges that prevent it from achieving an accurate and predictive description of nuclear spectral properties, not only for unknown exotic species but also for stable ordinary nuclei. In this project, the theory is advanced beyond the state of the art by implementing a new methodology for (i) evolving the fundamental strong interaction in the correlated media of atomic nuclei, (ii) ordering and navigating the increasing complexity of nucleonic propagation in such media with increasing particle number, and (iii) extrapolating the computation to astrophysical temperatures and densities. This effort is expected to reduce uncertainties in predictions of nuclear spectra for diverse applications. Graduate students engaged in the project are prepared to launch their careers in academia and industry. The novel results are integrated into university graduate courses, aiming at attracting young talents to the field of nuclear physics. This project focuses on the following theoretical and computational developments: (i) establishing a junction between the bare nuclear forces and their modification in correlated media of medium-mass and heavy nuclei by the direct solution of the equations of motion for the nucleonic correlation functions, (ii) many-body modeling for magnetic and charge-exchange nuclear responses, progressively increasing the correlation content which leads to increasing accuracy, and their extension to finite temperatures, (iii) numerical implementations of these effects in the relativistic framework on the base of the previously developed computer codes, (iv) numerical studies of the electric dipole, magnetic dipole, Gamow-Teller, and first-forbidden transitions in medium-heavy nuclei between nickel and tin mass regions, which are mostly relevant for rapid nucleosynthesis in neutron star mergers and core-collapse supernovae (CCSN). The results are analyzed in the context of current systematics and conditioned for use in astrophysical applications. In particular, the influence of microscopically calculated electron capture rates on the CCSN evolution scenarios is targeted. Underlying properties of exotic modes, such as the neutron skin dipole oscillation and its other multipole analogs, are extracted to reduce uncertainties on the parameters of the nuclear equation of state. 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.