Editor's Summary

8 January 2009

Quantum levitation

Space is not completely empty; the vacuum teems with quantum mechanical energy fluctuations able to generate an attractive force between objects that are very close to each other. This 'Casimir–Lifshitz' force can cause static friction or 'stiction' in nanomachines, which must be strongly reduced. Until now only attractive interactions have been reported but in theory, if vacuum is replaced by certain media, Casimir–Lifshitz forces should become repulsive. This has now been confirmed experimentally. Repulsion, weaker than the attractive force, was measured in a carefully chosen system of interacting materials immersed in fluid. The magnitude of both forces increases as separation decreases. The repulsive forces could conceivably allow quantum levitation of objects in a fluid and lead to new types of switchable nanoscale devices with ultra-low static friction. Levitation depends only on the dielectric properties of the various materials.

News and Views: Quantum physics: Quantum force turns repulsive

The experimental verification that a bizarre quantum effect — the Casimir force — can manifest itself in its repulsive form is pivotal not only for fundamental physics but also for nanotechnology.

Steve K. Lamoreaux

doi:10.1038/457156a

Full Text | PDF (1,015K)

Letter: Measured long-range repulsive Casimir–Lifshitz forces

J. N. Munday, Federico Capasso & V. Adrian Parsegian

doi:10.1038/nature07610

First paragraph | Full Text | PDF (248K) | Supplementary information