An experiment to measure the electric polarizability of $^{87}$Rb using a condensate interferometer

Atom interferometry using Bose-Einstein condensates has developed to a point at which intersting measurements are now feasible. We have demonstrated a condensate interferometer with coherence time over 70 ms and arm separations over $200 \mu$m. This allows each packet to be individually accessible. We plan to use this device to measure the electric polarizability of $^{87}$Rb by applying a precise electric field to one packet and not the other. By observing the resulting phase shift, we expect to be able to extract the polarizability with a relative accuracy better than $10^{-3}$. We will report on the experimental developments.