Ultracold quantum gases are small clouds of atoms which are cooled to such low temperatures that they can only be described by the laws of quantum mechanics. We are especially interested in their microscopic structure and local properties.
Our research interest comprises the following topics
Correlations in ultracold quantum gases
Study of pair correlations in condensed and thermal samples. Measurement of static and dynamical correlations in strongly interacting, low-dimensional quantum systems.
Dissipative processes in quantum gases
Investigation of the influence of local particle loss to the system. The studies are accompagnied by theoretical modelling via the Gross-Pitaevskii-Equation.
Tunneling dynamics in optical lattices
Preparation of tailored quantum states in optical lattices. In situ observation of first and higher order tunneling processes.
Developing concepts for the use of the dipole-dipole-interaction between Rydberg atoms for the implementation of long range interactions in optical lattices.
Ultracold ion sources
Identifying suitable ionization schemes for the generation of ultracold ion beams.
For the investigation of these topcis we have developed a unique manipulation and detection technique which is based on the principles of scanning electron microscopy. The following image sketches the working principle. A focussed electron beam intersects the quantum gas and locally produces ions. They are extracted with an eletrostatic field and subsequently detected.
This allows us to measure the distribution of the atoms inside the gas. Moreover, we can locally remove atoms from the system. The folllowing image shows a Bose-Einstein condensate in a one-dimensional optical lattice, where lattice sites have been selectively emptied.