Intuitive Analyses via Drift Theory

Humans are bad with probabilities, and the analysis of randomized algorithms offers many pitfalls for the human mind. Drift theory is an intuitive tool for reasoning about random processes. It allows turning expected stepwise changes into expected first-hitting times. While drift theory is used extensively by the community studying randomized search heuristics, it has seen hardly any applications outside of this field, in spite of many research questions which can be formulated as first-hitting times. We state the most useful drift theorems and demonstrate their use for various randomized processes, including approximating vertex cover, the coupon collector process, a random sorting algorithm, and the Moran process. Finally, we consider processes without expected stepwise change and give a lemma based on drift theory applicable in such scenarios without drift. We use this tool for the analysis of the gambler's ruin process, for a coloring algorithm, for an algorithm for 2-SAT, and for a version of the Moran process without bias

Low-Dimensional Traps for Bose-Fermi Mixtures

This thesis describes the design and realization of a novel experimental setup for the investigation of ultracold Bose-Fermi mixtures. The new setup combines a mixture experiment of 40K and 87Rb with one-dimensional trapping geometries that are accessible in the miniaturized wire traps of an atom chip. By additionally coupling the internal states of magnetically trapped atoms with radio-frequency (rf) fields, versatile state-selective and species-selective potentials can be created. One special case is the deformation of the static one-dimensional trap to a novel two-dimensional geometry in which the atoms are confined to the walls of a straight tube. An extensive numerical and experimental analysis of this trapping geometry with the aim of minimizing the variations in the trapping potential was performed. This leads to a new improved spatial arrangement for the wires that create the rf fields. The optimized wire layout was implemented in the new experimental setup and will allow the first realization of such a two-dimensional trap configuration with periodic boundary conditions. Results of experiments performed with a simplified arrangement of the rf wires allowed the observation of the two-dimensional regime with thermal atoms

Continuous Wave Terahertz Systems Based on 1.5 μm Telecom Technologies

Terahertz systems can profit from technologies developed originally for telecom applications. Recent developments on telecom-based key devices are summarized and ways towards CW systems with highest flexibility and excellent performance at reasonable costs are sketched

IT security of electronic communication systems in smart textile products

The SEKT research project, which is supported by the Federal Ministry of Education and Research, systematically investigates the integration and IT security of electronic communication systems in smart textile products. The main objectives are the scientific investigation of the IT security of Smart Textiles, the transfer of existing security concepts and the development of secure, innovative prototypes. The knowledge gained will be used to derive guidelines for the further procedure and courses for the textile and clothing industry will be developed, which will ensure an intensive multidisciplinary and cross-sectoral transfer of know-how. This challenge is to be met by an interdisciplinary team of scientists and companies from the textile and clothing industry and information technology. The actual status will be presented within the presentation