Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 4: Quantum Gases: Fermions I
Q 4.5: Talk
Monday, March 23, 2015, 12:30–12:45, K/HS2
Pairing in the vicinity of the BEC-BCS crossover — •Daniel Hoffmann1, Thomas Paintner1, Stefan Häussler1, Wladimir Schoch1, Wolfgang Limmer1, Benjamin Deissler1, Cheng Chin2, and Johannes Hecker Denschlag1 — 1Universität Ulm, Institut für Quantenmaterie, Ulm, Deutschland — 2University of Chicago, James Franck Institute, Chicago, USA
We investigate a mixture of paired (molecules or Cooper pairs) and unpaired atoms in the BEC-BCS crossover regime. For a given temperature, a thermodynamic equilibrium forms between atoms and pairs.
We use a 50-50 (30-70) mixture of the two lowest 6Li hyperfine spin states and set their interaction strength by adjusting the scattering length with the help of the Feshbach resonance at 832 G.
We then determine the temperature T* at which pair creation sets in. To do so we use RF spectroscopy as well as a magnetic field projection technique to determine the fraction of paired atoms at different temperatures.
Since T* differs from the critical temperature Tc for the superfluid transition it holds additional information on mixed systems. Therefore our results provide a deeper insight into pairing and pair-correlations.