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Q: Fachverband Quantenoptik und Photonik
Q 22: Quantengase: Fermionen im Gitter
Q 22.4: Talk
Tuesday, March 3, 2009, 15:00–15:15, VMP 6 HS-A
Attractively Interacting Fermionic Mixtures in Optical Lattices — •Lucia Hackermueller1, Ulrich Schneider1, Maria Moreno Cardoner1, Takuya Kitagawa2, Thorsten Best1, Sebastian Will1, Simon Braun1, Eugene Demler2, Belen Paredes1, and Immanuel Bloch1 — 1Staudingerweg 7, Universität Mainz, 55099 Mainz — 2Physics Department, Harvard University, Cambridge, MA 02138, USA
We present an experimental study of a balanced spin mixture of ultracold fermionic 40K in |F,mF⟩=|9/2,−9/2⟩ and |F, mF⟩=|9/2,−7/2⟩. The mixture is loaded into the combination of a three dimensional blue detuned optical lattice with a red detuned optical dipole trap, which allows an independent control of lattice depth and trapping potential. A Feshbach resonance located at 202.1G can be used to change the interaction strength and to create molecules by ramping adiabatically over the resonance. When the interaction is tuned from repulsive to attractive we measure a continuous decrease in cloud size and observe a minimum for intermediate attractive interactions, while for strong attractive interactions the size increases again. The increase in size coincides with a large fraction of the atomic cloud residing on doubly occupied sites and can be compared with the predictions of high temperature expansion theory. In addition we present measurements on the mobility of bound pairs in the optical lattice.