A chromium dipolar Fermi sea

TL;DR

This paper reports the creation of a degenerate Fermi gas of 53Cr atoms through sympathetic cooling with bosonic 52Cr atoms, achieving quantum degeneracy despite a small initial fermionic atom number.

Contribution

It demonstrates efficient sympathetic cooling of 53Cr fermions using 52Cr bosons, leading to a degenerate Fermi gas with a small atom number, highlighting the role of inter-isotope scattering.

Findings

Achieved a final temperature of 0.6 T_f with 10^3 53Cr atoms.

Used sympathetic cooling with 52Cr atoms to produce a degenerate Fermi gas.

Identified optimal inter-isotope scattering length for efficient cooling.

Abstract

We report on the production of a degenerate Fermi gas of 53Cr atoms, polarized in the state F=9/2, m_F=-9/2, by sympathetic cooling with bosonic S=3, m_S=-3 52Cr atoms. We load in an optical dipole trap 3.10^4 53Cr atoms with 10^6 52Cr atoms. Despite this initial small number of fermionic atoms, we reach a final temperature of T=0.6 T_f (Fermi temperature), with up to 10^3 53Cr atoms. This surprisingly efficient evaporation stems from an inter-isotope scattering length |a_{BF}| = (85+/- 10) a_{Bohr} which is small enough to reduce evaporative losses of the fermionic isotope, but large enough to insure thermalization.