# Berlin 2014 – wissenschaftliches Programm

## Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

# Q: Fachverband Quantenoptik und Photonik

## Q 31: Ultracold atoms, ions and BEC III (with A)

### Q 31.1: Hauptvortrag

### Mittwoch, 19. März 2014, 14:00–14:30, UDL HS3038

**Single charged impurities inside a Bose-Einstein condensate** — •Sebastian Hofferberth^{1}, Jonathan Balewski^{1}, Alexander Krupp^{1}, Anita Gaj^{1}, David Peter^{2}, Hanspeter Büchler^{2}, Robert Löw^{1}, and Tilman Pfau^{1} — ^{1}5. Phys. Institut, Universität Stuttgart, Germany — ^{2}Institut für Theoretische Physik III, Universität Stuttgart, Germany

We investigate the interaction of single charged impurtities with a Bose-Einstein condensate (BEC). We produce these impurities by exciting exactly one atom from the BEC to a Rydberg state. Since the ionic core and the Rydberg electron have vastly different mass and interaction range with the surrounding ground state atoms, their effect on the BEC can be observed separately. For low-L Rydberg states, the electron wavefunction is fully immersed in the BEC, and we observe electron-phonon coupling. We show that a single electron excites collective modes of the whole condensate. We also discuss the feasibility of studying the interaction of the ionic core with the BEC, which becomes possible if the electron is excited to a high-L states such that it is moved completely outside of the BEC. In this situation one could study ion-ground state Feshbach resonances at very low temperatures or trap the ion inside the BEC without any external electric fields.