Quantum-degenerate mixture of fermionic lithium and bosonic rubidium gases -: art. no. 170408

We report on the observation of sympathetic cooling of a cloud of fermionic Li-6 atoms which are thermally coupled to evaporatively cooled bosonic Rb-87. Using this technique we obtain a mixture of quantum-degenerate gases, where the Rb cloud is colder than the critical temperature for Bose-Einstein condensation and the Li cloud is colder than the Fermi temperature. From measurements of the thermalization velocity we estimate the interspecies s-wave triplet scattering length vertical bar alpha(mx)vertical bar = 20(-6)(+9)a(B). We found that the presence of residual rubidium atoms in the vertical bar 2, 1 > and the vertical bar 1, -1 > Zeeman substates gives rise to important losses due to inelastic collisions.