Licentiate Thesis: Feasibility study of resonant antiproton capture by ions and an open system approach to resonance decay

by Michael Genkin (Stockholm University, Department of Physics)

Friday 5 Dec 2008, 10:00 → 12:00 Europe/Stockholm

FB42

The present thesis is based on two different projects. The first part deals with resonant capture of antiprotons by electron excitation in highly charged hydrogen-like ions. The search for this process was mentioned by an experimental group at the Max Planck Institute in Heidelberg (Germany) as a possible future project at the Facility for Low Antiproton and Ion Research (FLAIR) at the "Gesellshaft für Schwerionenforschung" GSI in Darmstadt (Germany), which motivated the theoretical feasibility study in this thesis. Illustrative calculations were performed on the collision of antiprotons in the energy region E ≈ 0.13–0.14 keV with hydrogen-like calcium Ca19+. In particular, doubly excited resonant electron-antiproton states that can eventually be formed in such a collision are investigated and first approximate predictions for the cross section of resonant antiproton capture are made. The second part is also devoted to resonances, but on a more general basis. Due to the coupling to the continuum, a quantum system that contains resonances can be treated as an open quantum system. Its description in the framework of the Lindblad Markovian master equation is presented and compared to the unitary time evolution, governed by the Schrödinger equation, in a model potential. From this comparison, a relation between the resonance width and the phenomenological constants, that arise from the Lindblad operations, is derived.