Berlin 2014 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 4: Quantum gases: Fermions
Q 4.2: Talk
Monday, March 17, 2014, 10:45–11:00, DO24 Reuter Saal
Exploring the phase diagram of a strongly interacting 2D Fermi gas — •Martin Ries1, Mathias Neidig1, Andre Wenz1, Puneet Murthy1, Sebastian Pres1, Gerhard Zürn1, Thomas Lompe2, and Selim Jochim1 — 1Physikalisches Institut, Universität Heidelberg, INF 226, 69120 Heidelberg, Germany — 2Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
In this talk, we present our experiments with a two-dimensional gas of ultracold fermions in the strongly interacting regime.
We prepare a quantum degenerate quasi 2D sample of 6Li atoms in the lowest two hyperfine states. The gas is trapped in a single layer of a standing wave optical dipole trap.
We are able to extract several complementary properties from the sample: the density distribution can be probed by in situ imaging, phase correlations can be extracted from the self interference pattern in short time of flight, and using matter wave focusing [1,2], we can directly access the radial momentum distribution.
For deeply bound molecules, hence in the bosonic limit, we observe a clear bimodal momentum distribution. Additionally, the self interference pattern shows clear signatures of quasi long range phase coherence. We attribute these observations to the emergence of a quasi condensate.
By evaluating our system as a function of interaction strength and temperature, we are thus able to investigate the 2D equivalent of the BEC-BCS crossover.
[1] PRL 100, 090402 (2008) [2] PRL 89, 270404 (2002)