Original URL: http://www.theregister.co.uk/2007/08/07/quantum_levitation_incredible/

Boffins flick Quantum vacuum switch from suck to blow

Goldenballs will power gecko hoverships, raygun gloves

By Lewis Page

Posted in Science, 7th August 2007 12:44 GMT

Cartoon-loving boffins from University of St Andrews believe they have found a way to reverse the "Casimir force" which causes really small things to stick to each other. This has been widely written up, usually with the word "levitation" in the headline.

The University press release notes that:

"Professor Ulf Leonhardt and Dr Thomas Philbin of the University's School of Physics & Astronomy believe that they can engineer the Casimir force of quantum physics to cause an object to repel rather than attract another in a vacuum.

"Casimir force (discovered in 1948 and first measured in 1997) can be demonstrated in a gecko's ability to stick to a surface with just one toe ..."

This suggests some truly exciting possibilities. Firstly, that boffins used geckoes to demonstrate the Casimir force in '97, after taking 49 years to notice them; and secondly that the Scottish-based researchers have now found a way to make gecko feet frictionless rather than sticky - or even that geckoes, at any rate, could be made to levitate.

This raises visions of a beautiful but perhaps ethically troubling future with mighty hover vessels plying the skies, lifted on the backs of hundreds of genetically or surgically modified ground-repelling geckoes. No doubt in time some kind of squamatan-effects coating or generator would replace the early aerial gecko-galleons but in the meantime the potential for lizard abuse would be horrific.

Perhaps fortunately, hopes of hovering mid-air geckoes or even comically slippery skating ones are dashed as soon as one looks at the scientists' own webpage, rather than the university press office one.

The boffins do their best to jazz things up with a few gratuitous Incredibles stills, but the bad news is all too plain. Geckoes can stick to ceilings - even glass ones, apparently, of the type metaphorically encountered by upward-bound female biz execs - due to the Van der Waals force between temporary dipoles in molecules. The Casimir stickiness, seemingly, is caused "roughly speaking" by "difference in the pressure of the quantum vacuum."

Of course any fool knows about the quantum vacuum between all the atoms and molecules and stuff which make up the world around us. As the Scottish-based boffins say:

"Empty space is not empty, but is filled with the quantum vacuum ... The energy of the quantum vacuum, the 'zero-point energy,' is infinite according to our present theories. Clearly, this [is not true] - it would make the electromagnetic field infinitely massive, because [of] E=mc2. The empty electromagnetic field would collapse under the weight of its own gravity [and the entire universe would implode] ... Nevertheless, the zero-point energy results in perfectly finite and experimentally confirmed facts, for example the Casimir force."

Or, freely paraphrasing, we don't really know what's going on here but zero-point energy and the Casimir force are real and could conceivably rip open the fabric of the space-time continuum and destroy the universe. The St Andrews team appear to endorse the idea that zero-point effects could at least be used to produce some kind of ultra-powerful devastating energy ray, as developed by "Syndrome" the supervillain in The Incredibles. On their webpage they show a pic of Syndrome blasting something, captioned:

"Syndrome from Pixar's The Incredibles levitates things on zero-point energy."

The effect was tested in '97, not by a hilarious sequence of pranks played on geckoes, nor by the use of astounding energy-blaster raygun gauntlets, but (of course, duh) by measuring the Casimir forcefield generated by a solid golden ball on a "nanofabricated silicon swing."

So far, so good. But Leonhardt and Philbin were just punting some ideas around in the lab one day, when they came up with the notion of reversing the Casimir goldenball tractor-beam effect between conductive materials by slipping a sheet of "left-handed metamaterial" made of "nanofabricated metal" in between them. This has probably had boffins worldwide slapping their foreheads with cries of "cah! why didn't I think of that!"

Anyway, after a bunch of hard sums, the two eggheads have worked out that you could make a Casimir repellor platform out of unspecified nano stuff, perhaps involving golden balls in some way. You could then lay a half-micron thick aluminium-foil mirror on it and the mirror would miraculously hover just above the platform.

According to the scientists in their rather headache-inducing paper (pdf), "the foil would levitate, carried by zero-point fluctuations."

Or in other words, the quantum vacuum would have switched from suck to blow. In a controllable and completely non-universe-destroying way, of course. Hover ships and raygun gloves still not really on the drawing board.

This would be great, nevertheless - who hasn't wrestled from time to time with the tricky problem of how to keep one's unbelievably thin mirror foil from touching anything?

Well alright, maybe a lot of us don't have that kind of problem. But nano or micro-machine designers do; the chaps who make so-called micro-electro-mechanical systems - for instance the Pentagon's cyborg insect spy project, which aims to implant a soulless controlling machine core inside living creatures. The death-tech boffins might be able to use Leonhardt and Philbin's ideas to create frictionless bearings, allowing the internal Pentagon micro-droid to manipulate hapless living creatures from inside, wearing them like a living cloak.

And that's just one of the potential benefits. Besides, there's still hope for the squamatan-effects sky cruiser hover platform concept. The Van der Waals force is apparently related to the Casimir phenomenon, so there could well be some future gecko-scale applications down the road.

The raygun-gloves thing, though, seems to have been the scientific equivalent of writing "SEX! Ha ha, now we've got you reading ..."®