arXiv:1606.09472 · Physical Review A
Impact of Casimir-Polder interaction on Poisson-spot diffraction at a dielectric sphere
Joshua Leo Hemmerich, Robert G. Bennett, Thomas J.G. Reisinger, Stefan Nimmrichter, Johannes Fiedler, Horst Hahn, H. Gleiter, Stefan Yoshi Buhmann
Abstract
Diffraction of matter waves is an important demonstration of the fact that objects in nature possess a mixture of particlelike and wavelike properties. Unlike in the case of light diffraction, matter waves are subject to a vacuum-mediated interaction with diffraction obstacles. Here we present a detailed account of this effect through the calculation of the attractive Casimir-Polder potential between a dielectric sphere and an atomic beam. Furthermore, we use our calculated potential to make predictions about the diffraction patterns to be observed in an ongoing experiment where a beam of indium atoms is diffracted around a silicon-dioxide sphere. The result is an amplification of the on-axis bright feature, which is the matter-wave analog of the well-known ``Poisson spot'' from optics. Our treatment confirms that the diffraction patterns resulting from our complete account of the sphere Casimir-Polder potential are indistinguishable from those found via a large-sphere nonretarded approximation in the discussed experiments, establishing the latter as an adequate model.