Quantum Levitation Anyone?

Quantum effects cause strange things, such as the Casimir-Lifshitz interaction. Now, a team at Harvard has used this effect to create a repulsive force that can be used to create a frictionless quantum levitation between two surfaces!

Artistic rendering: quantum levitation
Capasso Group, Harvard University

The Casimir-Lifshitz interaction was originally predicted in 1948 by Hendrik Casimir (and extended by Evgeny Lifshitz in 1956). The idea is that the quantum effects of the vacuum actually create a slight electromagnetic field, which means that two uncharged conducting plates will develop a slight attractive force, pulling them together. This effect has been measured with great precision over the years, and even works in some cases when the vacuum between the plates is filled with certain sorts of liquids.

Until this new work by Harvard, however, no one had ever observed a repulsive Casimir-Lifshitz interaction, even though theoretically it should be possible. The team immersed a gold-coated sphere in liquid, measuring the force as it was attracted to a metal plate and then repelled from a silica plate. The next step is to take the repulsive effect and perform an experiment that demonstrates the predicted levitation.

Both the attractive and repulsive effects have a potential applications in the creation of tiny nanotechnology devices, which are built at a scale so small that designers may well be able to utilize these effects in a meaningful way.

Related Articles:

• Harvard University - Capasso group, with access to the full research paper free of charge
• Reuters - U.S. scientists learn how to levitate tiny objects
• Nature - News & Views Quantum physics: Quantum force turns repulsive, or see the Editor's summary,
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