Tuesday, January 22, 2008

Casimir Force

The Casimir effect is a phenomenon found in quantum field theory that sounds like pure science fiction. But recently, scientists have been finding practical applications for this bizarre concept. First let's describe the Casimir effect and then I'll point you to an article about it.

Basically, the Casimir effect is a quantum mechanical force that arises from the vacuum energy or "zero point" field. The so-called zero point energy results from a left over infinite sum you get when writing down the energy of a quantum field. So in everyday terms you can think of the vacuum energy as an energy field that fills all of empty space, everywhere.

Casimir did some calculations and discovered that if you had two conducting metal plates in a vacuum, the vacuum energy would cause them to move closer together. The bottom line here is put two metal plates in a vacuum, and they are going to be attracted to one another, even though from a classical perspective you would expect nothing to happen since the vacuum is supposedly empty space. The Casimir effect proves that this is not the case, and is one more illustration of how quantum theory leads to interesting and bizarre effects. The gory details on the Casimir effect can be found in this Wikipedia article, I have to warn you its pretty mathematical and hard to wade through.


So let's get to the interesting part. Recently, scientists have figured out how to exploit the Casimir effect in nanotechnology. Apparently "nanomachines" have a tendency to stop running (like all machines do) but they figured out how to use the Casimir force to counteract this problem. This is described here:


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