Impact of Casimir-Polder interaction on Poisson-spot diffraction at a dielectric sphere

TL;DR

This paper investigates how the Casimir-Polder interaction influences matter-wave diffraction around a dielectric sphere, predicting an amplified Poisson spot and confirming the adequacy of simplified models in experimental contexts.

Contribution

It provides a detailed calculation of the Casimir-Polder potential and its effect on matter-wave diffraction, linking quantum vacuum interactions to observable diffraction patterns.

Findings

Casimir-Polder potential amplifies the Poisson spot in matter-wave diffraction.

Complete potential calculations match simplified large-sphere models.

Predictions align with ongoing experimental observations.

Abstract

Diffraction of matter-waves is an important demonstration of the fact that objects in nature possess a mixture of particle-like and wave-like 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 analogue 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 non-retarded approximation in the discussed experiments, establishing the latter as an adequate model.