Parametric cooling of a degenerate Fermi gas in an optical trap

TL;DR

This paper introduces a parametric cooling method for degenerate Fermi gases in optical traps, utilizing anharmonic trap modulation to selectively remove high-energy atoms and achieve lower temperatures.

Contribution

The study presents a new cooling technique based on trap modulation that effectively reduces the energy of a degenerate Fermi gas, especially along the axial direction.

Findings

Cooling efficiency depends on modulation frequency and amplitude.

Anharmonicity enables anisotropic energy distribution in the gas.

Axial energy can be cooled to the ground state value.

Abstract

We demonstrate a novel technique for cooling a degenerate Fermi gas in a crossed-beam optical dipole trap, where high-energy atoms can be selectively removed from the trap by modulating the stiffness of the trapping potential with anharmonic trapping frequencies. We measure the dependence of the cooling effect on the frequency and amplitude of the parametric modulations. It is found that the large anharmonicity along the axial trapping potential allows to generate a degenerate Fermi gas with anisotropic energy distribution, in which the cloud energy in the axial direction can be reduced to the ground state value.