Rapid sympathetic cooling to Fermi degeneracy on a chip

Abstract

Neutral fermions present new opportunities for testing models of many-body quantum systems, realizing precision atom interferometry, producing ultra-cold molecules, and investigating fundamental forces. However, since they were first observed1, quantum degenerate Fermi gases (DFGs) have continued to be challenging to produce, and have been realized in only a handful of laboratories2,3,4,5,6,7,8,9,10. In this letter, we report the production of a DFG using a simple apparatus based on a microfabricated magnetic trap. Similar approaches applied to Bose–Einstein condensation of 87Rb (refs 11,12) have accelerated evaporative cooling and eliminated the need for multiple vacuum chambers. We demonstrate sympathetic cooling for the first time in a microtrap, and cool 40K to Fermi degeneracy in just six seconds—faster than has been possible in conventional magnetic traps. To understand our sympathetic cooling trajectory, we measure the temperature dependence of the 40 K–87Rb cross-section and observe its Ramsauer–Townsend reduction.

Cite this article

Aubin, S., Myrskog, S., Extavour, M. et al. Rapid sympathetic cooling to Fermi degeneracy on a chip. Nature Phys 2, 384–387 (2006). https://doi.org/10.1038/nphys309

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