The measured forces agree fairly well with predictions from the Casimir-Lifshitz theory. Any discrepancies, the researchers say, are most likely due to insufficiently precise knowledge of the electromagnetic properties of the materials used in the experiments.
As well as verifying experimentally an esoteric aspect of quantum mechanics, the existence of a repulsive force could be a boon in the design of nanodevices with tiny moving parts. Such devices must cope with friction, the force that resists sliding motion of touching surfaces because of the slight adhesion between them. For nanocomponents of the right composition, immersed in a suitable liquid, the repulsive Casimir-Lifshitz force would amount to a kind of quantum levitation that would keep surfaces slightly apart and allow easy movement.
Bromobenzene, chosen in these experiments for its electrical properties, would not be a good practical choice, Capasso says, because of safety concerns. But many other suitable liquids exist, he says. Teflon could substitute for silica, and metals other than gold would also produce repulsion, so that designers of nanodevices would have range of building materials to draw on.