Feshbach resonances in $p$-wave three-body recombination within Fermi-Fermi mixtures of open-shell ${}^6$Li and closed-shell ${}^{173}$Yb atoms

Abstract

We report on observations and modeling of interspecies magnetic Feshbach resonances in dilute ultracold mixtures of open-shell alkali-metal ${}^6$Li and closed-shell ${}^{173}$Yb atoms with temperatures just above quantum degeneracy for both fermionic species. Resonances are located by detecting magnetic-field-dependent atom loss due to three-body recombination. We resolve closely-located resonances that originate from a weak separation-dependent hyperfine coupling between the electronic spin of ${}^6$Li and the nuclear spin of ${}^{173}$Yb, and confirm their magnetic field spacing by ab initio electronic-structure calculations. Through quantitative comparisons of theoretical atom-loss profiles and experimental data at various temperatures between 1 $\hat{I}¼$K and 20 $\hat{I}¼$K, we show that three-body recombination in fermionic mixtures has a $p$-wave Wigner threshold behavior leading to characteristic asymmetric loss profiles. Such resonances can be applied towards the formation of ultracold doublet ground-state molecules and quantum simulation of superfluid $p$-wave pairing.

13 pages, 7 figures, 3 tables