Hannover 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
Q: Fachverband Quantenoptik und Photonik
Q 16: Quantum Gases: Interaction Effects I
Q 16.4: Vortrag
Dienstag, 9. März 2010, 15:00–15:15, E 001
Phase separation in a thermal mixture of ultracold atoms — •Frank Münchow, Florian Baumer, Cristian Bruni, Simon Hübner, and Axel Görlitz — Institut für Experimentalphysik, HHU Düsseldorf, Germany
A fundamental question that arises if two gases of atoms are trapped in the same trap is whether the two species mix or phase separation occurs. Generally, a condition for phase separation in a thermal mixture is that the interspecies interaction energy is extremely large and exceeds the thermal energy. Therefore, interaction-driven phase separation has not been observed in ultracold atom experiments, so far. Here, we report on our recent results on mixtures of ultracold Yb and Rb in a hybrid trap consisting of a bichromatic optical potential superimposed on a magnetic trap. For a specific combination of isotopes, namely 174Yb and 87Rb, we have observed an almost complete spatial separation of thermal clouds of 174Yb and 87Rb at temperatures in the low µK regime. In the particular trapping geometry, the presence of an ultracold 87Rb cloud (≈ 107 atoms) leads to a strong repulsive interaction potential for the ≈ 105 174Yb atoms which are repelled from the trap center. The phase separation implies intrinsically large repulsive interspecies interaction for the specific isotopic mixture and indicates an interspecies scattering length greater than 10000 a0.