Double Degenerate Bose-Fermi Mixture of Strontium and Lithium

TL;DR

This paper reports the creation of a degenerate mixture of fermionic lithium and bosonic strontium, demonstrating quantum degeneracy and estimating interspecies interactions in a novel Bose-Fermi system.

Contribution

It presents the first realization of a degenerate Bose-Fermi mixture of $^{84}$Sr and $^{6}$Li, including measurements of degeneracy and interspecies scattering length.

Findings

Achieved $T/T_F=0.33$ with $^{6}$Li in contact with $^{84}$Sr BEC.

Measured interspecies s-wave scattering length as approximately 7.1$a_0$.

Demonstrated quantum degeneracy in a Sr-Li mixture.

Abstract

We report on the attainment of a degenerate Fermi gas of $\rm^{6}Li$ in contact with a Bose-Einstein condensate (BEC) of $^{84}$Sr. A degeneracy of $T/T_F=0.33(3)$ is observed with $1.6\times10^5$ $^{6}$Li atoms in the two lowest energy hyperfine states together with an almost pure BEC of $3.1\times10^5$ $^{84}$Sr atoms. The elastic s-wave scattering length between $^6$Li and $^{84}$Sr is estimated to be $|a_{\rm^{6}Li-\rm^{84}Sr}|=(7.1_{-1.7}^{+2.6})a_0$ ($a_0$ being the Bohr radius) from measured interspecies thermalization rates in an optical dipole trap.