Rostock 2019 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 35: Quantum Gases (Fermions) I
Q 35.7: Vortrag
Mittwoch, 13. März 2019, 15:45–16:00, S HS 037 Informatik
Pairing on the BEC side of a fermionic system — •Manuel Jäger1, Thomas Paintner1, Daniel Hoffmann1, Wladimir Schoch1, Wolfgang Limmer1, Michele Pini2, Pierbagio Pieri2, Giancarlo Strinati2, Cheng Chin3, and Johannes Hecker Denschlag1 — 1Universität Ulm, Institut für Quantenmaterie, Deutschland — 2University of Camerino, School of Science and Technology, Physics Division, Italy — 3University of Chicago, James Franck Institute, USA
We investigate the pair formation in a two-component fermionic system on the BEC side of unitarity. For a given interaction strength and temperature a thermodynamic equilibrium between unbound fermions and preformed pairs forms. Especially in the vicinity of unitarity, such a strongly interacting many-body system is still not fully understood.
In order to investigatge this system experimentally, we use a 50-50 mixture of the two lowest 6 Li Zeemann 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 fraction of paired atoms at different temperatures and interaction strengths using optical spectroscopy. The results are compared with a classical calculation, a self-consistent t-matrix approach and a thermal equilibrium model based on quantum statistics and mean field interaction.
The measurements and the calculations agree quite well, indicating that even at interaction parameters up to (kFa)−1 = 0.5 the fermionic many-body system can be still viewed as dominantly consisting of a mix of atoms and molecules.