Knöll, Marco (2024)
Ab Initio Theory and Machine Learning for Hypernuclei.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00027654
Dissertation, Erstveröffentlichung, Verlagsversion
Kurzbeschreibung (Abstract)
Systems with strangeness, such as hypernuclei, offer a unique window into the dynamics of the strong force beyond traditional nucleonic systems. Building on recent developments of the hypernuclear no-core shell model with realistic baryonic interactions from chiral effective field theory, this work presents advancements on the three major frontiers of ab initio hypernuclear structure theory: the refinement of the hyperon-nucleon interaction, precision calculations with quantified uncertainties, and the push to medium-mass hypernuclei.
Firstly, we present a novel extrapolation tool supplementing the no-core shell model that is based on artificial neural networks. Due to their pattern recognition abilities, they hold great promise in enhancing precision and uncertainty estimation in (hyper)nuclear many-body calculations, giving access to extrapolation procedures and meaningful many-body uncertainties for observables beyond ground-state energies. Moreover, they demonstrate the universality of observable-specific convergence patterns through applications across nucleonic and hyperonic systems.
Secondly, we address the chiral hyperon-nucleon interaction, which is poorly constrained due to the scarce experimental scattering data available. Based on precise many-body calculations we demonstrate the potential of ground-state and spectroscopic data for p-shell hypernuclei as additional constraints for the hyperon-nucleon interaction. We present an optimized interaction at leading order, which is then applied across a range of p-shell hypernuclei. Through only minor adjustments of the low-energy constants we alleviate the previous overbinding of the hyperon and significantly improve the agreement with experimental data in light hypernuclei.
Lastly, we present pioneering work on ab initio calculations of medium-mass hypernuclei. In a first step, we extend the concept of natural orbitals as an optimized single-particle basis to hypernuclei. We find that the associated wavefunctions yield great insight into the structure of hypernuclei, allowing us to identify Lambda-Helium-5 as a candidate for a hyperon halo. From there we develop a hyperon-attached in-medium no-core shell model framework and present the first ever ab initio calculation of Lambda-Calcium-41.
By addressing these challenges, this work contributes to a deeper understanding of the strong force in hypernuclear systems and lays the groundwork for future investigations.
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2024 | ||||
Autor(en): | Knöll, Marco | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Ab Initio Theory and Machine Learning for Hypernuclei | ||||
Sprache: | Englisch | ||||
Referenten: | Roth, Prof. Dr. Robert ; Schwenk, Prof. Ph.D Achim | ||||
Publikationsjahr: | 11 Juli 2024 | ||||
Ort: | Darmstadt | ||||
Kollation: | vii, 155 Seiten | ||||
Datum der mündlichen Prüfung: | 1 Juli 2024 | ||||
DOI: | 10.26083/tuprints-00027654 | ||||
URL / URN: | https://tuprints.ulb.tu-darmstadt.de/27654 | ||||
Kurzbeschreibung (Abstract): | Systems with strangeness, such as hypernuclei, offer a unique window into the dynamics of the strong force beyond traditional nucleonic systems. Building on recent developments of the hypernuclear no-core shell model with realistic baryonic interactions from chiral effective field theory, this work presents advancements on the three major frontiers of ab initio hypernuclear structure theory: the refinement of the hyperon-nucleon interaction, precision calculations with quantified uncertainties, and the push to medium-mass hypernuclei. Firstly, we present a novel extrapolation tool supplementing the no-core shell model that is based on artificial neural networks. Due to their pattern recognition abilities, they hold great promise in enhancing precision and uncertainty estimation in (hyper)nuclear many-body calculations, giving access to extrapolation procedures and meaningful many-body uncertainties for observables beyond ground-state energies. Moreover, they demonstrate the universality of observable-specific convergence patterns through applications across nucleonic and hyperonic systems. Secondly, we address the chiral hyperon-nucleon interaction, which is poorly constrained due to the scarce experimental scattering data available. Based on precise many-body calculations we demonstrate the potential of ground-state and spectroscopic data for p-shell hypernuclei as additional constraints for the hyperon-nucleon interaction. We present an optimized interaction at leading order, which is then applied across a range of p-shell hypernuclei. Through only minor adjustments of the low-energy constants we alleviate the previous overbinding of the hyperon and significantly improve the agreement with experimental data in light hypernuclei. Lastly, we present pioneering work on ab initio calculations of medium-mass hypernuclei. In a first step, we extend the concept of natural orbitals as an optimized single-particle basis to hypernuclei. We find that the associated wavefunctions yield great insight into the structure of hypernuclei, allowing us to identify Lambda-Helium-5 as a candidate for a hyperon halo. From there we develop a hyperon-attached in-medium no-core shell model framework and present the first ever ab initio calculation of Lambda-Calcium-41. By addressing these challenges, this work contributes to a deeper understanding of the strong force in hypernuclear systems and lays the groundwork for future investigations. |
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Status: | Verlagsversion | ||||
URN: | urn:nbn:de:tuda-tuprints-276547 | ||||
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 |
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TU-Projekte: | DFG|SFB1245|A02 Roth | ||||
Hinterlegungsdatum: | 11 Jul 2024 11:36 | ||||
Letzte Änderung: | 12 Jul 2024 09:52 | ||||
PPN: | |||||
Referenten: | Roth, Prof. Dr. Robert ; Schwenk, Prof. Ph.D Achim | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 1 Juli 2024 | ||||
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