Measurement of the Casimir-Polder force through center-of-mass oscillations of a Bose-Einstein condensate

We have performed a measurement of the Casimir-Polder force using a magnetically trapped 87-Rb Bose-Einstein condensate. By detecting perturbations of the frequency of center-of-mass oscillations of the condensate perpendicular to the surface, we are able to detect this force at a distance ~5 microns, significantly farther than has been previously achieved, and at a precision approaching that needed to detect the modification due to thermal radiation. Additionally, this technique provides a limit for the presence of non-Newtonian gravity forces in the ~1 micron range.