Quantum Resonances in a Complex-Momentum Basis

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dc.contributor.authorBengtsson, Jonathan
dc.contributor.authorGranström, Pontus
dc.contributor.authorEmbréus, Ola
dc.contributor.authorEricsson, Vincent
dc.contributor.authorWireklint, Nils
dc.contributor.departmentChalmers tekniska högskola / Institutionen för fundamental fysiksv
dc.contributor.departmentChalmers University of Technology / Department of Fundamental Physicsen
dc.date.accessioned2019-07-03T13:11:51Z
dc.date.available2019-07-03T13:11:51Z
dc.date.issued2013
dc.description.abstractResonances are important features of open quantum systems. We study, in particular, unbound and loosely bound nuclear systems. We model 5He and 6He in a few-body picture, consisting of an alpha-particle core with one and two valence neutrons respectively. Basis-expansion theory is briefly explained and then used to expand the nuclear system in the harmonic oscillator and momentum bases. We extend the momentum basis into the complex plane, obtaining solutions that form a Berggren basis. With the complex-momentum method we are able to reproduce experimentally observed resonances in 5He. The 5He Berggren basis solutions are used as a single-particle basis to create many-body states in which we expand the 6He system. For the two-body interaction between the neutrons, we use two different phenomenological models: a Gaussian and a Surface Delta Interaction (SDI). The strength of each interaction is fitted to reproduce the 6He ground state energy. With the Gaussian interaction we do not obtain the 6He resonance, whereas with the SDI we do. The relevant parts of the second quantization formalism is summarized, and we briefly discuss a possible implementation.
dc.identifier.urihttps://hdl.handle.net/20.500.12380/179709
dc.language.isoeng
dc.setspec.uppsokPhysicsChemistryMaths
dc.subjectGrundläggande vetenskaper
dc.subjectFysik
dc.subjectSubatomär fysik
dc.subjectKärnfysik
dc.subjectLågenergifysik
dc.subjectBasic Sciences
dc.subjectPhysical Sciences
dc.subjectSubatomic Physics
dc.subjectNuclear physics
dc.subjectLow energy physics
dc.titleQuantum Resonances in a Complex-Momentum Basis
dc.type.degreeExamensarbete för kandidatexamensv
dc.type.degreeBachelor Thesisen
dc.type.uppsokM2
local.programmeEngineering Physics (300 hp)
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