arXiv subjects
Publications and source records attributed to J. Denschlag.
We give a comprehensive overview of the development of micro traps, from the first experiments on guiding atoms using current carrying wires in the early 1990's to the creation of a BEC on an atom chip.
We demonstrate a spatially resolved autocorrelation measurement with a Bose-Einstein condensate (BEC) and measure the evolution of the spatial profile of its quantum mechanical phase. Upon release of the BEC from the magnetic trap, its phase develops a form that we measure to be quadratic in the spatial coordinate. Our experiments also reveal the effects of the repulsive interaction between two overlapping BEC wavepackets and we measure the small momentum they impart to each other.
We have investigated the processes N($π$, $π$)N and N($π$, $η$)N close to eta threshold using a simple, nonrelativistic Lee model which has the advantage of being analytically solvable. It is then possible to study the Riemann sheets of the S-matrix and the behavior of its resonance poles especially close to threshold. A theoretical simulation of the experimental cusp effect at eta threshold leads to a characteristic distribution of poles on the Riemann sheets. We find a pole located in the $4^{th}$ Riemann sheet that up to now has not been discussed. It belongs to the cusp peak at eta threshold. In addition we obtain the surprising result using the Lee model that the resonance $S_{11}(1535)$ does not play a large role. The main features of the experimental data can be reproduced without explicitly introducing this resonance. Furthermore, we have also studied the reactions N($γ$, $π$)N and N($γ$, $η$)N and find reasonable agreement between the data and both models with and without the $S_{11}(1535)$ resonance.