Abstract
We report on the observation of magnetic Feshbach resonances in a Fermi-Fermi mixture of ultracold atoms with extreme mass imbalance and on their unique p-wave dominated three-body recombination processes. Our system consists of open-shell alkali-metal 6Li and closed-shell 173Yb atoms, both spin polarized and held at various temperatures between 1 and 20 μK. We confirm that Feshbach resonances in this system are solely the result of a weak separation-dependent hyperfine coupling between the electronic spin of 6Li and the nuclear spin of 173Yb. Our analysis also shows that three-body recombination rates are controlled by the identical fermion nature of the mixture, even in the presence of s-wave collisions between the two species and with recombination rate coefficients outside the Wigner threshold regime at our lowest temperature. Specifically, a comparison of experimental and theoretical line shapes of the recombination process indicates that the characteristic asymmetric line shape as a function of applied magnetic field and a maximum recombination rate coefficient that is independent of temperature can only be explained by triatomic collisions with nonzero, p-wave total orbital angular momentum. The resonances can be used to form ultracold doublet ground-state molecules and to simulate quantum superfluidity in mass-imbalanced mixtures.
Highlights
Magnetic Feshbach resonances (MFRs) are valuable tools in ultracold bosonic and fermionic atomic gases, providing access to tunable interactions between atoms [1,2]
We report on the distinctive temperature dependence of the resonant three-body recombination processes that
We show that three-body recombination rates are controlled by the identical fermion nature of the mixture, even though s-wave interspecies collisions are present and even when the recombination rate coefficients are outside the Wigner threshold regime at our temperatures
Summary
Magnetic Feshbach resonances (MFRs) are valuable tools in ultracold bosonic and fermionic atomic gases, providing access to tunable interactions between atoms [1,2]. Recombination in atomic gases has been studied around weak Feshbach resonances [11,12] Their collision-energy dependence has been examined in Ref. Recombination is dominated by trimer p-wave collisions and, as we show, has an asymmetric line shape and a temperature-independent maximum loss rate coefficient Such temperature-dependent studies have only been performed in bosonic systems [30,31,32,33,34] where the rate coefficients are controlled by either s- or d-wave trimer collisions and p-wave collisions do not play a role. II–VI we report on the observation and quantitative model of Feshbach resonances in spin-polarized ultracold mixtures of fermionic 6Li and fermionic 173Yb. In Secs.
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