Extensions to the No-Core Shell Model [electronic resource] : Importance-Truncation, Regulators and Reactions /
Kruse, Michael Karl Gerhard.author.
Extensions to the No-Core Shell Model presents three extensions to the No-Core Shell Model (NCSM) that allow for calculations of heavier nuclei, specifically for the p-shell nuclei. The Importance-Truncated NCSM (IT-NCSM) formulated on arguments of multi-configurational perturbation theory selects a small set of basis states from the initially large basis space in which the Hamiltonian is diagonalized. Previous IT-NCSM calculations have proven reliable, however, there has been no thorough investigation of the inherent error in the truncated IT-NCSM calculations. This thesis provides a detailed study of IT-NCSM calculations and compares them to full NCSM calculations to judge the accuracy of IT-NCSM in heavier nuclei. When IT-NCSM calculations are performed, one often needs to extrapolate the ground-state energy from the finite basis (or model) spaces to the full NCSM model space. In this thesis a careful investigation of the extrapolation procedures was performed. On a related note, extrapolations in the NCSM are commonplace, but up to recently did not have the ultraviolet (UV) or infrared (IR) physics under control. This work additionally presents a method that maps the NCSM parameters into an effective-field theory inspired framework, in which the UV and IR physics are treated appropriately. The NCSM is well-suited to describe bound-state properties of nuclei, but is not well-adapted to describe loosely bound systems, such as the exotic nuclei near the neutron drip line. With the inclusion of the Resonating Group Method (RGM), the NCSM / RGM can provide a first-principles description of exotic nuclei and the first extension of the NCSM.
Doctoral Thesis accepted by the University of Arizona, USA.
Includes bibliographical references.
Introduction to Low-Energy Nuclear Physics -- The No Core Shell Model -- Importance Truncated No Core Shell Model -- UV and IR Properties of the NCSM -- Extending the NCSM with the RGM -- Conclusion.
Extensions to the No-Core Shell Model presents three extensions to the No-Core Shell Model (NCSM) that allow for calculations of heavier nuclei, specifically for the p-shell nuclei. The Importance-Truncated NCSM (IT-NCSM) formulated on arguments of multi-configurational perturbation theory selects a small set of basis states from the initially large basis space in which the Hamiltonian is diagonalized. Previous IT-NCSM calculations have proven reliable, however, there has been no thorough investigation of the inherent error in the truncated IT-NCSM calculations. This thesis provides a detailed study of IT-NCSM calculations and compares them to full NCSM calculations to judge the accuracy of IT-NCSM in heavier nuclei. When IT-NCSM calculations are performed, one often needs to extrapolate the ground-state energy from the finite basis (or model) spaces to the full NCSM model space. In this thesis a careful investigation of the extrapolation procedures was performed. On a related note, extrapolations in the NCSM are commonplace, but up to recently did not have the ultraviolet (UV) or infrared (IR) physics under control. This work additionally presents a method that maps the NCSM parameters into an effective-field theory inspired framework, in which the UV and IR physics are treated appropriately. The NCSM is well-suited to describe bound-state properties of nuclei, but is not well-adapted to describe loosely bound systems, such as the exotic nuclei near the neutron drip line. With the inclusion of the Resonating Group Method (RGM), the NCSM / RGM can provide a first-principles description of exotic nuclei and the first extension of the NCSM.
Elementary particles (Physics).
Quantum field theory.
Nuclear physics.
Heavy ions.
String theory.
Elementary Particles, Quantum Field Theory.
Nuclear Physics, Heavy Ions, Hadrons.
Quantum Field Theories, String Theory.