Laser cooling of trapped Fermi gases

Abstract

The collective Raman cooling of trapped one- and two-component Fermi gases is considered. We obtain the quantum master equation that describes the laser cooling in the festina lente regime, for which the heating due to photon reabsorption can be neglected. For the two-component case the collisional processes are described within the formalism of quantum Boltzmann master equation. The inhibition of the spontaneous emission can be overcome by properly adjusting the spontaneous Raman rate during the cooling. Our numerical results based in Monte Carlo simulations of the corresponding rate equations, show that three-dimensional temperatures of the order of $0.08 T_F$ (single-component) and $0.03 T_F$ (two-component) can be achieved. We investigate the statistical properties of the equilibrium distribution of the laser-cooled gas, showing that the number fluctuations are enhanced compared with the thermal distribution close to the Fermi surface. Finally, we analyze the heating related to the background losses, concluding that our laser-cooling scheme should maintain the temperature of the gas without significant additional losses.