Hüther, Thomas (2021)
Families of Chiral Two- plus Three-Nucleon Interactions for Accurate Nuclear Structure Studies.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00018588
Dissertation, Erstveröffentlichung, Verlagsversion
Kurzbeschreibung (Abstract)
Chiral effective field theory allows for a systematically improvable construction of nuclear interactions and currents rooted in quantum chromodynamics (QCD). In this thesis we propose families of chiral nucleon-nucleon (NN) plus three-nucleon (3N) interactions and develop a framework to incorporate nuclear exchange-current contributions to the $M1$ operator in importance-truncated no-core shell model (IT-NCSM) calculations.
The interaction families base on the Entem, Machleidt and Nosyk NN interactions, which are supplemented at next-to-next-to-leading order (N$^2$LO) and next-to-next-to-next-to-leading order (N$^3$LO) with 3N interactions consistent in chiral order, non-local regulator, and cutoff values. We study the dependence of observables of light- and medium-mass nuclei on the 3N low-energy constants (LECs). Based on the results, we propose two alternative optimization procedures for the LECs. One optimizes the ground-state energies of $^{3}$H and $^{4}$He and the other the ground-state energies of $^{3}$H and $^{16}$O.
The performance of both interaction families is explored for ground-state energies and radii of light- and medium-mass nuclei as well as for spectra of p-shell nuclei. In these calculations, we give a fully estimation of the uncertainties for both the many-body method and the interaction. The uncertainties due to the chiral truncation are estimated with a state-of-the-art approach rooted in Bayesian statistics. Both interaction families lead to robust results for the considered observables. In particular, the inclusion of the ground-state energy of $^{16}$O in the optimization procedure leads to energies and radii, which reproduce the experimental values up to the nickel isotopes well.
For precision studies of electromagnetic observables like multipole moments and transition strengths, we need in addition to an accurate interaction also consistent exchange currents. In this work, we develop the necessary framework to include exchange-current contributions to the $M1$ operator in IT-NCSM calculations. This comprises the correct treatment in the similarity renormalization group (SRG) as well as the transformation into a suitable single-particle basis representation. This leads to the first fully chiral determination of the magnetic dipole moment of the ground state of $^{6}$Li as well as the magnetic dipole transition strength from the first $0^+$ to the $1^+$ ground state of $^{6}$Li including the next-to leading order (NLO) current contribution to the $M1$ operator. This study shows that both the consistent treatment in the SRG and the exchange-current contribution to the $M1$ operator are important to match theory and experiment.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2021 | ||||
| Autor(en): | Hüther, Thomas | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Families of Chiral Two- plus Three-Nucleon Interactions for Accurate Nuclear Structure Studies | ||||
| Sprache: | Englisch | ||||
| Referenten: | Roth, Prof. Dr. Robert ; Hebeler, PD Dr. Kai | ||||
| Publikationsjahr: | 2021 | ||||
| Ort: | Darmstadt | ||||
| Kollation: | viii, 126 Seiten | ||||
| Datum der mündlichen Prüfung: | 17 Mai 2021 | ||||
| DOI: | 10.26083/tuprints-00018588 | ||||
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/18588 | ||||
| Kurzbeschreibung (Abstract): | Chiral effective field theory allows for a systematically improvable construction of nuclear interactions and currents rooted in quantum chromodynamics (QCD). In this thesis we propose families of chiral nucleon-nucleon (NN) plus three-nucleon (3N) interactions and develop a framework to incorporate nuclear exchange-current contributions to the $M1$ operator in importance-truncated no-core shell model (IT-NCSM) calculations. The interaction families base on the Entem, Machleidt and Nosyk NN interactions, which are supplemented at next-to-next-to-leading order (N$^2$LO) and next-to-next-to-next-to-leading order (N$^3$LO) with 3N interactions consistent in chiral order, non-local regulator, and cutoff values. We study the dependence of observables of light- and medium-mass nuclei on the 3N low-energy constants (LECs). Based on the results, we propose two alternative optimization procedures for the LECs. One optimizes the ground-state energies of $^{3}$H and $^{4}$He and the other the ground-state energies of $^{3}$H and $^{16}$O. The performance of both interaction families is explored for ground-state energies and radii of light- and medium-mass nuclei as well as for spectra of p-shell nuclei. In these calculations, we give a fully estimation of the uncertainties for both the many-body method and the interaction. The uncertainties due to the chiral truncation are estimated with a state-of-the-art approach rooted in Bayesian statistics. Both interaction families lead to robust results for the considered observables. In particular, the inclusion of the ground-state energy of $^{16}$O in the optimization procedure leads to energies and radii, which reproduce the experimental values up to the nickel isotopes well. For precision studies of electromagnetic observables like multipole moments and transition strengths, we need in addition to an accurate interaction also consistent exchange currents. In this work, we develop the necessary framework to include exchange-current contributions to the $M1$ operator in IT-NCSM calculations. This comprises the correct treatment in the similarity renormalization group (SRG) as well as the transformation into a suitable single-particle basis representation. This leads to the first fully chiral determination of the magnetic dipole moment of the ground state of $^{6}$Li as well as the magnetic dipole transition strength from the first $0^+$ to the $1^+$ ground state of $^{6}$Li including the next-to leading order (NLO) current contribution to the $M1$ operator. This study shows that both the consistent treatment in the SRG and the exchange-current contribution to the $M1$ operator are important to match theory and experiment. |
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| Status: | Verlagsversion | ||||
| URN: | urn:nbn:de:tuda-tuprints-185888 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik | ||||
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik 05 Fachbereich Physik > Institut für Kernphysik 05 Fachbereich Physik > Institut für Kernphysik > Theoretische Kernphysik 05 Fachbereich Physik > Institut für Kernphysik > Theoretische Kernphysik > Kern- und Vielteilchenphysik |
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| TU-Projekte: | DFG|SFB1245|A02 Roth | ||||
| Hinterlegungsdatum: | 01 Jun 2021 07:38 | ||||
| Letzte Änderung: | 08 Jun 2021 11:45 | ||||
| PPN: | |||||
| Referenten: | Roth, Prof. Dr. Robert ; Hebeler, PD Dr. Kai | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 17 Mai 2021 | ||||
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| Suche nach Titel in: | TUfind oder in Google | ||||
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