Few-Body Physics in Quantum Gases [Elektronische Ressource] / Kerstin Helfrich. Mathematisch-Naturwissenschaftliche Fakultät

Few-Body Physics in Quantum GasesDissertationzurErlangung des Doktorgrades (Dr. rer. nat.)derMathematisch{Naturwissenschaftlichen FakultatderRheinischen Friedrich{Wilhelms{Universitat Bonnvorgelegt vonKerstin HelfrichausAscha enburgBonn 2011Angefertigt mit Genehmigung derMathematisch-Naturwissenschaftlichen Fakult at derRheinischen Friedrich-Wilhelms-Universit at BonnDiese Dissertation ist auf dem Hochschulschriftenserver der ULB Bonn unterhttp://hss.ulb.uni-bonn.de/diss online elektronisch publiziert.1. Gutachter: Prof. Dr. Hans-Werner Hammer2. Gutachter: Prof. Dr. Achim RoschTag der Promotion: 14.10.2011Erscheinungsjahr: 2011AbstractFew-body e ects play an important role for the understanding of ultracold quantum gases.We make use of an e ective eld theory approach to investigate various aspects of universalfew-body physics close to a Feshbach resonance. That is the regime where the scatteringlength is large compared to all other length scales of the system and thus determines theobservables. It is also the regime where the E mov e ect whose main characteristic is theoccurrence of a sequence of three-body bound states becomes important. At unitarity, i.e.,for diverging scattering length, the ratio of binding energies of neighboring states approachesa constant. The existence of those trimers can be captured by a single three-body parameterand in uences observables such as recombination rates.