Darmstadt 2008 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 27: Poster Quantengase

Q 27.21: Poster

Tuesday, March 11, 2008, 16:30–19:00, Poster C2

Interaction-controlled transport of an ultracold Fermi gas — •Robert Jördens¹, Niels Strohmaier¹, Yosuke Takasu², Kenneth Günter³, Michael Köhl⁴, Henning Moritz¹, and Tilman Esslinger¹ — ¹Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland — ²Department for Electronic Science and Engineering, Kyoto University, Kyoto 615-8510, Japan — ³Laboratoire Kastler Brossel, 75005 Paris, France — ⁴Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom

We explore the transport properties of an interacting Fermi gas in a three-dimensional optical lattice. In analogy to the characterization of transport behavior in condensed matter systems through conductivity measurements, we study the atom cloud’s center of mass motion after a sudden displacement of the trap minimum.

Different interaction strengths and lattice fillings are shown to have a characteristic influence on the dynamics. With increasingly strong attractive interactions the weakly damped oscillation, observed for the non-interacting case, turns into a slow drift: local pairs with a reduced tunneling rate are formed for strong inter-atomic attraction. This interpretation is supported by a measurement of the number of doubly occupied lattices sites. Application of this technique in other interaction regimes, lattice depths and fillings in the Fermi-Hubbard model may provide a tool for the identification of quantum phases such as the fermionic Mott-insulator. Experimental results on repulsively interacting Fermi gases will be presented.