  A magnetically trapped 87Rb Bose-Einstein condensate is used as a sensitive
probe of short-range electrical forces. In particular, the electric
polarization of, and the subsequent electric field generated by, 87Rb
adsorbates on conducting and insulating surfaces is measured by characterizing
perturbations to the magnetic trapping potential using high-Q condensate
excitations. The nature of the alterations to the electrical properties of Rb
adsorbates is studied on titanium (metal) and silicon (semiconductor) surfaces,
which exhibit nearly identical properties, and on glass (insulator), which
displays a smaller transitory electrical effect. The limits of this technique
in detecting electrical fields and ramifications for measurements of
short-range forces near surfaces are discussed.
