Green's functions and the nuclear many-body problem

Washington University, Saint Louis MO

Investigators

Abstract

The origin of the chemical elements is one of the fundamental problems in nuclear physics and astrophysics, and the detailed understanding of the structural and dynamical properties of nuclei is the key ingredient for progress in understanding the nucleosynthesis process that allows for the formation of atomic nuclei from constituent nucleons (protons and nucleons). One of the challenges posed by this problem concerns the study of nuclei that feature a large imbalance between the number of protons and neutrons. These nuclei are generally unstable, leading to radioactivity, and have important societal relevance for industry, medicine and defense applications. In that broader context, this project will provide theoretical support for the science programs at leading experimental facilities, such as the future Facility for Rare Isotope Beams (FRIB) under construction on the campus of Michigan State University. In particular, the PI and his students will continue the development of a theoretical approach aimed at providing a consistent description of nuclear structure and nuclear reactions needed to analyze the experimental data at FRIB and other nuclear physics facilities. The PI will mentor graduate students in this research and collaborate with experimental colleagues who will perform related experiments. This project aims at providing a simultaneous description of positive energy nucleons, the domain of elastic scattering, and bound nucleons, the domain of nuclear structure, using the framework of the propagator method of quantum mechanics. The application of the propagator method will employ the nonlocal implementation of the description of the potentials that allows for the accurate description of ground-state properties using the method of dispersion relations. Accompanying the implementation of the propagator method to describe all relevant experimental data, including elastic scattering cross sections and matter and charge distributions, will be the calculation of these properties using the same framework but starting from the underlying interactions between nucleons as constrained by the symmetries of the fundamental theory of quarks and gluons, Quantum Chromo Dynamics, and the available data for the properties of two nucleons. Such calculations will be applied with a new scheme that allows the ab initio calculation of properties of heavier nuclei that have not been studied in this way to date. The method will also be applied to calculations of the superfluid properties of neutron stars.