KEY POINTS:
LONDON - Levitation - the magical ability to rise when there seems to be no external force at work - may be possible in the real world, two British scientists have conjectured.
Disappointingly, even if they are right, their theory will only apply to very small objects, not to human beings.
The importance of the theory, if it is borne out, will be felt in nanotechnology and the construction of micro-machines, where its effects could be revolutionary.
It depends on a quirk of nature that allows particles to pop into existence from nowhere.
Known as the 'Casimir force', it was predicted by quantum physicists in 1948, and measured for the first time in 1997.
If two objects, such as mirrors, are very close to one another, the Casimir can push them together.
This can be a major hazard in micro-machines, when it causes minute components to stick together, creating friction in the works.
Now, Professor Ulf Leonhardt and Dr Thomas Philbin, from the University of St Andrews in Scotland, believe they have worked out a way of reversing the Casimir force so that it pushes objects apart.
It could lead to the construction of micro machines free from friction, with moving parts that levitate.
Prof Leonhardt said: "The Casimir force is the ultimate cause of friction in the nano-world, in particular in some micro-electromechanical systems.
Such systems already play an important role - for example tiny mechanical devices which trigger a car airbag to inflate or those which power tiny 'lab on chip' devices used for drugs testing or chemical analysis.
Micro or nano-machines could run smoother and with less or no friction at all if one can manipulate the force."Research by the two theoretical physicists, due for publication in the August edition of the New Journal of Physics, suggests that the Casimir effect can be reversed by using a 'perfect' lens, which bends light in the opposite direction from a normal lens.
However, the day when a human being will be able to emulate TS Eliot's notorious cat, Macavity - whose "powers of levitation would make a fakir stare" - are still very far off.
"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," said Prof Leonhardt.
"For now, human levitation remains the subject of cartoons, fairytales and tales of the paranormal."
- INDEPENDENT
