Micro-machines given a scientific lift by levitation theory

Micro-machines given a scientific lift by levitation theory
Published: 06 August 2007
Independent UK

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 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 how to reverse 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.

Professor Leonhardt said: "The Casimir force is the ultimate cause of friction in the nano-world...Micro or nano-machines could run with little or no friction 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, "[This process would] only be possible for micro-objects with the current technology, since this quantum force acts only at short ranges," said Professor Leonhardt.