Optimal cooling strategies for magnetically trapped atomic Fermi-Bose mixtures

Abstract

We discuss cooling efficiency for different-species Fermi-Bose mixtures in magnetic traps. A better heat capacity matching between the two atomic species is achieved by a proper choice of the Bose cooler and the magnetically trappable hyperfine states of the mixture. When a partial spatial overlap between the two species is also taken into account, the deepest Fermi degeneracy is obtained for an optimal value of the trapping frequency ratio between the two species. This can be achieved by assisting the magnetic trap with a deconfining light beam, as shown in the case of fermionic $^{6}\mathrm{Li}$ mixed with $^{23}\mathrm{Na}$, $^{87}\mathrm{Rb}$, and $^{133}\mathrm{Cs}$, with optimal conditions found for the not yet explored $^{6}\mathrm{Li}\penalty1000-\hskip0pt^{87}\mathrm{Rb}$ mixture.