Scottish physicists at prestigious St Andrews University have developed a method of making tiny objects levitate by reversing a mysterious force of nature. Normally when you hear that someone is using “the force” to levitate objects, you have to wonder if they’re a confused Star Wars fan trying to be a Jedi warrior. However, these scientists say they are only using their knowledge of real physics to create an incredible solution to a real engineering problem.
Professor Ulf Leonhardt and Dr Thomas Philbin have worked out how to turn the normally ‘sticky' quantum force of empty space from attraction to repulsion using a specially developed lens placed between two objects.
"In order to reduce friction in the nanoworld, turning nature's stickiness into repulsion could be the ultimate remedy. Instead of sticking together, parts of micromachinery would levitate," explained Professor Leonhardt.
While it is also theoretically possible for humans to levitate, scientists are a long way off from developing the kind of technology needed for levitation on a larger scale.
"At the moment, in practice it is only going to be possible for micro-objects with the current technology, since this quantum force is small and acts only at short ranges. For now, human levitation remains the subject of cartoons, fairytales and tales of the paranormal," cautions Leonhardt.
For smaller parts, the levitation will occur using a phenomenon called the "Casimir force", which was predicted by quantum physicists back in 1948. It wasn’t proven to exist until scientists were finally able to measure it ten years ago. Scientists are still struggling to fully understand it.
The force is caused by a little understood quirk of nature which seemingly enables particles to “pop into existence” from out of nowhere. This creates a force that pushes together two objects placed very close to each other. It can also be demonstrated by a gecko's ability to stick to a surface with just one toe.
Other scientists are eagerly taking notice of this fascinating research. The Scottish pair's theory is now being examined by a leading American scientist, who plans to put the ideas into practice. Dr Frederico Capasso, of Harvard University in the United States, is currently also working on ways to manipulate the Casimir effect. Philbin said, "We've shown him our work and he's very interested."
The technique has the potential to revolutionize nanotechnology and the design of micro-machines. The scientists predict their discovery will ultimately lead to frictionless micro-machines with moving parts that levitate.
Because the Casimir force has little effect on everyday life—it is usually ignored. Nevertheless, it becomes an extremely important force when trying to develop tiny switches and micro-machines, since their components have a tendency to stick to each other.
Professor Leonhardt explains how controlling this force will revolutionize micro-engineering, "The Casimir force is the ultimate cause of friction in the nano-world, in particular in some micro-electromechanical systems. Micro or nano machines could run smoother and with less—or no friction at all—if one can manipulate the force."
* This research is due to appear in this month's edition of the New Journal of Physics.
Posted by Rebecca Sato
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