Species selectivity of adiabatic RF potentials

We report on the successful implementation of a species-selective double-well micromagnetic trap on an atom chip. Adiabatic RF potentials have recently been used for coherent beam splitting [1], and been suggested for species-selective manipulation [2]. We report on our implementation of this suggestion for a $^{40}$K-$^{87}$Rb Bose-Fermi mixture, where the radio frequency resonances are distinct since the Lande g$_F$ factors differ between the two elements. We demonstrate, for instance, that beam splitting of $^{87}$Rb can occur while $^{40}$K remains confined in an overlapping single-well potential [3]. We also report on our progress toward direct observation of relative number squeezing in an RF beam splitter, for which indirect evidence was recently reported [4].\newline \newline Refs: [1] T. Schumm et al., Nature Phys. {\bf 1}, 57 (2005). [2] Ph.W. Courteille et al., J. Phys. B: At. Mol. Opt. Phys. {\bf 39}, 1055 (2006). [3] M. H. T. Extavour et al., Atomic Physics {\bf 20}, 241 (2006); also cond-mat/0609259. [4] G.-B. Jo et al., Phys. Rev. Lett. {\bf 98}, 030407 (2007).