Measurement of the Casimir-Polder Force at Sub-micro Distance Scales using an Atomic Beam D. Suresh [Ph.D Thesis]

Doctor of Philosophy Bangalore University, Bangalore 2004

This thesis describes an effort wherein we have developed a versatile atomic beam
apparatus. The objective is to study the Casimir-Polder interaction of the atoms with
surfaces. The apparatus is capable of measuring isotopic abundances in the atomic
beam and can therefore probe the differences in the responses of various isotopes.
Study of these interactions has gained signifcance in recent times because Casimir
interactions constitute the dominant background in any measurement of gravitation
at distances less than 1 mm. An accurate measurement of these forces gives rise
to stringent limits on the strength and distance scale of new forces postulated in
theoretical attempts to unify gravity with the standard model of particle physics.
The Casimir-polder force is interesting from another point of view as well. It is a
fully quantum electrodynamical effect with the added attraction of being measurable
at macroscopic distances of several microns.
We describe here the construction and operation of an apparatus which was,
but recently, completed and present some preliminary observations of transmission
through cavities about 10 ¹m in width. We also give a brief review of similar exper-
iments aimed at furthering our understanding of atom-surface interactions. At the
end, we indicate possible future directions in this pursuit.