August 6th, 2007
The secret of levitation
Several U.K. news sources are reporting today that two Scottish researchers have developed a theory to ‘levitate’ very small objects. According to The Scotsman, their theory involves what is known as the ‘Casimir force.’ By reversing the Casimir force so that it repels instead of attracts, their discovery could ultimately lead to frictionless nanomachines with moving parts that levitate. They started by sandwiching a lens between two conducting plates and they were able to ‘levitate’ ultra-thin mirrors. But what might be true with nanoscale objects is not yet true for humans. As said one of the scientists, “For now, human levitation remains the subject of cartoons, fairy tales and tales of the paranormal.”
You can see above an “artist’s impression of a thin mirror being held up above another mirror by the quantum levitation effect.” “The repulsive Casimir force of a left-handed material may balance the weight of one of the mirrors, letting it levitate on zero-point fluctuations.” (Credit: Ulf Leonhardt research group)
This research work has been led by Professor Ulf Leonhardt and Dr Thomas Philbin, a member of his Quantum Information and Optics group at the University of St Andrews. You’ll find more details on Leonhardt’s Quantum Levitation research page.
Here are some short quotes from Leonhardt as reported by The Scotsman. “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.”
For more information, this research work is scheduled to be published in the August 2007 issue of the New Journal of Physics under the name “Quantum levitation by left-handed metamaterials.” You’ll find more details about metamaterials and left-handed metamaterials on on this Wikipedia page. And thanks to arXiv.org, here is a link to the abstract. “Left-handed metamaterials make perfect lenses that image classical electromagnetic fields with significantly higher resolution than the diffraction limit. Here we consider the quantum physics of such devices. We show that the Casimir force of two conducting plates may turn from attraction to repulsion if a perfect lens is sandwiched between them. For optical left-handed metamaterials this repulsive force of the quantum vacuum may levitate ultra-thin mirrors.”
You also can read the full paper which has already been revised 4 times since last year (PDF format, 13 pages, 160 KB). Finally, if you’re really interested in this subject and the interactions between the theories of Maxwell’s electromagnetism and Einstein’s general relativity, please read a presentation (PDF format, 8 pages, 3.03 MB).
Sources: Alastair Dalton, The Scotsman, August 6, 2007; and various websites
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