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Updated: Dec 29, 2025

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Thermalization and Sub-Poissonian Density Fluctuations in a Degenerate Molecular Fermi Gas
William G Tobias1, Kyle Matsuda1, Giacomo Valtolina1
1JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
Abstract:
We observe thermalization in the production of a degenerate Fermi gas of polar ^{40}K^{87}Rb molecules. By measuring the atom-dimer elastic scattering cross section near the Feshbach resonance, we show that Feshbach molecules rapidly reach thermal equilibrium with both parent atomic species. Equilibrium is essentially maintained through coherent transfer to the ground state. Sub-Poissonian density fluctuations in Feshbach and ground-state molecules are measured, giving an independent characterization of degeneracy and directly probing the molecular Fermi-Dirac distribution.
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