# Stuttgart 2012 – wissenschaftliches Programm

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# Q: Fachverband Quantenoptik und Photonik

## Q 1: Quantengase: Bosonen 1

### Q 1.5: Vortrag

### Montag, 12. März 2012, 11:30–11:45, V53.01

**Cool quantum gases "going ballistic": quantum-dynamics in micro-gravity** — •R. Walser, R. Nolte, and M. Schneider — Institute for Applied Physics, TU Darmstadt, Germany

Optical imaging of matter-waves after releasing them from confining traps is the standard method to analyze the properties of the matter-wave in the expanded form. This gives access to the structure of the matter-wave within the optical resolution limit. In Earth-bound laboratories this expansion is usually limited by the height of the vacuum system, when the free falling atoms hit the bottom of the chamber. In the current micro-gravity experiments of the QUANTUS collaboration at ZARM [1], this limitation is lifted as the container is co-propagating (≈ 100 m). The ballistic expansion is limited by much lesser constraints giving raise to macroscopic condensates, visible by the naked eye (2mm).

In this presentation, we will discuss theoretical aspects of modeling the release of a trapped quantum gas [2] with time-dependent Hartree-Fock Bogoliubov [3] equations and simulations in the hydrodynamical regime within the Wigner approximation.

[1] T. van Zoest, *et al.*, Science **328**, 1540, (2010).

[2] G. Nandi, R. Walser, E. Kajari and W. P. Schleich, Phys. Rev. A, **76**, 63617 (2007).

[3] R. Walser, J. Williams, J. Cooper and M. Holland, Phys. Rev. A, **59**, 3878 (1999).

Acknowledgment: Deutsche Luft und Raumfahrt Agentur DLR (50WM 1137)