Scientists discover way of levitating small objects
It might sound like something out of a Harry Potter novel, but there is nothing fictional about the discovery made by UK scientists that makes tiny objects levitate. The breakthrough is expected to have significant benefits for the nanotechnology sector. Theoretical scientists from the University of St Andrews in the UK found that they were able to reverse a quantum force, known as the Casimir force, which usually causes objects to stick together. The phenomenon, which was first discovered in 1948, is a physical force that is exerted between separate objects due to resonance of all-pervasive energy fields in the space between the objects. The fields cause atoms to stick together. An example of this quantum force in action is the gecko's ability to attach itself to surfaces. While this physical force has no effect on our everyday lives, it can have serious implications for nanotechnology. 'Casimir force is the ultimate cause of friction in the nano-world, in particular in some microelectromechanical systems,' says Professor Ulf Leonhardt of the University's School of Physics and Astronomy. '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,' added the Professor. The scientists managed to reverse the force by placing a small 'perfect' lens between two objects. The lens is made out of artificial metamaterial that has a negative index-of-refraction. This bends a beam of light the opposite way to normal and enables the metamaterial to modify the resonance in the gap between the two objects, thus reversing the Casimir force. One object could therefore hover over another at a distance where the repulsive Casimir force of the quantum vacuum balances the weight of the plate; the plate levitates on, quite literally, nothing. The scientists say that the lens is strong enough to levitate an aluminium mirror that is 500 nanometres thick. '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,' said Professor Leonhardt. Though it is possible in principle for humans to levitate, the scientists say there is a long way to go before the technology is developed for such feats. '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,' said Professor Leonhardt.
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