Phase Separation in a Fermi-Bose Mixture of $^6$Li and $^{41}$K
ORAL
Abstract
We report on the observation of phase separation between a $^{41}$K Bose-Einstein condensate (BEC) and a $^{6}$Li Fermi sea with strong repulsive interspecies interactions. After evaporation in an optical dipole trap, we obtain a BEC of $10^4$ $^{41}$K atoms and a Fermi sea of $10^5$ $^{6}$Li atoms with $T/T_F< 0.07$. We explore this double-degenerate mixture by tuning the heternonuclear interaction with the help of a Feshbach resonance at $335.08\,$G. We use three-body recombination as a probe to study the overlap between the two species for various interaction strengths. We see a decrease in losses when the interactions become strongly repulsive and compare the loss rate to that of a non-condensed bosonic cloud. In a phase-separated mixture, losses only happen at the interface of the two species and are therefore reduced, when compared to a mixed phase of both species. To understand our loss rate results, we calculate the spatial overlap between the two components with a mean-field model. This model fits nicely to our experimental results and reveals effects beyond the local density approximation (LDA).
*This work is supported by the Austrian Science Fund FWF within the collaborative research grant FoQuS.
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