# Heidelberg 2015 – wissenschaftliches Programm

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# Q: Fachverband Quantenoptik und Photonik

## Q 15: Poster: Quantum Optics and Photonics I

### Q 15.53: Poster

### Montag, 23. März 2015, 17:00–19:00, C/Foyer

**Non-equilibrium mass transport in bosonic quantum systems** — •Christian Baals, Bodhaditya Santra, Ralf Labouvie, Simon Heun, and Herwig Ott — Research Center OPTIMAS and Fachbereich Physik, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany

We study the dynamics of a Bose-Einstein condensate (BEC) after a quench of the density distribution. To this purpose, we use a tightly focused electron beam which is implemented in a standard BEC apparatus. The electron beam serves as a detection device where the atoms are ionized by electron-impact, extracted from the atomic cloud and detected. Additionally, the electron beam allows us to tailor the atomic density distribution and to locally apply losses as a source of dissipation. Our aim is to investigate the dynamics of such an out-of-equilibrium situation. In a first experiment, we shine the electron beam on an atomic BEC and measure the losses as a function of the dissipation strength. Above a critical limit, we observe the appearance of quantum Zeno dynamics. A similar situation can be created when the BEC is loaded into a one-dimensional optical lattice and a lattice site is continuously probed by the electron beam. Initially removing atoms from one lattice site and observing the ensuing refilling dynamics, makes it possible to measure the conductivity of the system. We find that the interplay between the interaction energy, the tunneling coupling and intrinsic collisions leads to negative differential conductivity.