An ideal Bose-Einstein condensate: From Anderson localization to precision measurements

Here we describe two different experiments that show the high potentialities offered by combining a tunable interacting BEC of potassium atoms and periodic potentials. In the first experiment we trap the ideal BEC in a quasi-periodic potential obtained Superimposing two laser standing waves with incommensurate wavelengths. in this case we observe the Anderson transition from extended to exponentially localized states with coherent matter waves. We clearly demonstrate localization by investigating transport properties, spatial and momentum distributions. Since the interaction in the condensate can be controlled, thanks to a broad Feshbach resonance, this system represents a novel tool to Solve fundamental questions on the interplay of disorder and interaction and to explore exotic quantum phases.