Prediction of a measurable sign change in the Casimir force using a magnetic fluid

TL;DR

This paper demonstrates controllable quantum levitation via Casimir forces in a ferrofluid system, showing measurable sign changes and transitions between attraction and repulsion influenced by material properties.

Contribution

It introduces a novel system using a ferrofluid immersed in a mixture to control Casimir force sign changes and quantum trapping effects.

Findings

Casimir force sign change observed at specific distances

Thermal and quantum effects influence trapping magnitude

Material choices enable control over Casimir interactions

Abstract

We demonstrate quantum levitation controlled by Casimir forces acting between a polystyrene surface and a Teflon-coated metallic substrate immersed in a mixture of Toluene and magnetite particles. This system experiences repulsion-attraction transitions in the Casimir interaction for distances where the effect is measurable. This Casimir trapping can be controlled by clever choices of metallic and ferrofluid materials, which are directly linked to the emergence of the trapping effect. Thermal and quantum contributions are investigated in detail, showing how the optical and magnetic properties of the ferrofluid and other materials affect the magnitude of the trapping and its distance range of observability.