It's not the first time that the effects of the Casimir force, a force which can alter the good behavior of nanomachines, are measured. (Check this PhysicsWeb's article for example.)
But according to this Purdue University news release, they have never been measured so precisely.
[Note: if you need more explanation about the Casimir force, read this brief introduction from Wikipedia.]
For technical details about the experiment, read the abstract of this research paper, "Measurement of the Casimir Force between Dissimilar Metals." It has been published by the Physical Review Letters (Vol. 31, Article 050402, August 1, 2003 issue).
The first precise measurement of the Casimir force between dissimilar metals is reported. The attractive force, between a Cu layer evaporated on a microelectromechanical torsional oscillator and an Au layer deposited on an Al 2O3sphere, was measured dynamically. Measurements were performed for separations in the 0.2-2 µm range. The results agree to better than 1 percent in the 0.2-0.5 µm range with a theoretical model that takes into account the finite conductivity and roughness of the two metals.
Now, we can return to plain english and ask ourselves why this new experiment is important.
The Casimir force has to do with the minute pressure that real and virtual photons of light exert when they bump against an object. High quantities of photons are constantly striking you from all directions, emitted by everything from your stovetop to distant stars.
"If an object creates heat or light, it shines with photons - even your own body," said Purdue physicist Ephraim Fischbach. "Usually when a piece of metal is struck with a photon from one direction, another is hitting it on its opposite side, and the effects cancel out, and it doesn't move."
But when two very small objects are extremely close together, the "photonic pressure" on the outside of each object is stronger than on the inside, which tends to drive the two toward each other.
"This effect is comparatively weak on large objects, but at the nanoscale it can really push things around," Fischbach said. "When the teeth of two tiny gears come together, for example, the Casimir force could push them together so strongly that they would stick and freeze up the nanomachinery. We needed to measure the force's effects accurately so we could factor it into future investigations."
Still, more research needs to be done before the Casimir force can help nanotechnologists instead of being a hurdle. When it's done, real applications will come.
"Some computer industry experts think that future generations of computers will use light, rather than electricity, to carry data," Fischbach said. "To manipulate light beams at that scale, we will likely need tiny mirrors that can pivot to reflect photons down different channels. Knowledge of the Casimir force - which essentially deals with photons' ability to move small objects - could help us make those mirrors move with precision."
Another, more contemporary, application could be the fiber-optic industry, which also moves information-carrying photons around.
Source: Chad Boutin, Purdue University, August 11, 2003
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