Double-degenerate Bose-Fermi mixture of strontium

TL;DR

This paper reports the creation of a degenerate mixture of spin-polarized fermionic 87-Sr and Bose-Einstein condensate of 84-Sr, demonstrating thermal contact and cooling to quantum degeneracy in a strontium mixture.

Contribution

First realization of a double-degenerate Bose-Fermi mixture of strontium isotopes with thermal contact and quantum degeneracy.

Findings

Achieved T/T_F=0.30(5) for 87-Sr fermions

Produced an almost pure 84-Sr BEC of 10^5 atoms

Demonstrated thermalization via interisotope collisions

Abstract

We report on the attainment of a spin-polarized Fermi sea of 87-Sr in thermal contact with a Bose-Einstein condensate (BEC) of 84-Sr. Interisotope collisions thermalize the fermions with the bosons during evaporative cooling. A degeneracy of T/T_F=0.30(5) is reached with 2x10^4 87-Sr atoms together with an almost pure 84-Sr BEC of 10^5 atoms.