Recoil-limited laser cooling of 87Sr atoms near the Fermi temperature

Takashi Mukaiyama

I. E. Mazets, Boris G. Matisov

Takashi Mukaiyama, Hidetoshi Katori, T. Ido +2 more

A dynamic magneto-optical trap, which relies on the rapid randomization of population in Zeeman substates, has been demonstrated for fermionic strontium atoms on the $^{1}S_{0}\ensuremath{-}^{3}P_{1}$ intercombination transition. The obtained sample, $1\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms at a temperature of $2\text{ }\ensuremath{\mu}\mathrm{K}$ in the trap, was further Doppler cooled and polarized in a far-off resonant optical lattice to achieve 2 times the Fermi temperature.

Wei Qi, Ming-Cheng Liang, Han Zhang +4 more

Abstract We report the experimental realization of quantum degenerate Fermi gases of 87Sr atoms under controlled 10- and dual-nuclear-spin configurations. Based on laser cooling and evaporative cooling, we achieve an ultracold Fermi gas of 105 atoms equally distributed over 10 spin states, with a temperature of T/TF=0.21. We further prepare a dual-spin gas by optically pumping atoms to the mF=9/2 and mF=7/2 states and observe a slightly lower T/TF than that for a 10-spin gas under the same trapping condition, showing efficient evaporative cooling under a decreasing number N of spin states ( N ≥ 2 ) despite the increasing importance of Pauli exclusion. Given that rethermalization becomes less efficient with N approaching unity, we evaporatively cool an almost polarized gas to 130 nK. The simple and efficient preparation of ultracold Fermi gases of 87Sr with tunable spin configurations provides a first step towards engineering topological quantum systems.

Uday Kumar Khan

王少凯, Qiang Wang, 林弋戈 +5 more