Chromium dipolar Fermi sea

We report on the production of a degenerate Fermi gas of 53Cr atoms, polarized in the state 𝐹=9/2,Β π‘šπΉ=βˆ’9/2, by sympathetic cooling with bosonic 𝑆=3, π‘šπ‘†=βˆ’3Β 52Cr atoms.
arXiv:1411.4634 (2014) / Phys. Rev. A 91, 011603(R) (2015)

We load in an optical dipole trap 3Γ—104⁒ 53Cr atoms with 106 52Cr atoms. Despite the initial small number of fermionic atoms, we reach a final temperature of 𝑇≃0.6×𝑇𝑓 (Fermi temperature), with up to 103 53Cr atoms. This surprisingly efficient evaporation stems from an interisotope scattering length |π‘Žπ΅β’πΉβ’|=80⁒(Β±10)β’π‘Žπ΅ (Bohr radius) which is small enough to reduce evaporative losses of the fermionic isotope, but large enough to assure thermalization.

Time evolution of 52 Cr temperature and atom number of both isotopes. t=0 corresponds to the end of the IR trap loading. The crossed dipole trap is fully loaded at t=7 s. The evaporation ends at t=12 s.