The hunt for a repulsive Casimir force

Repulsive Casimir force

Place a couple of infinite metal plates just a few micrometers apart and ya can measure the so-called Casimir force pushing them together.

The thinkin is that virtual particles are constantly a-popping and a-peaking in and outta existence. When the particles bang into the plate, they exert a force which is normally balanced out by the pressure of virtual particles on the other side.

But put another plate close enough and the distance between them is too small to allow for the existence of certain virtual particles. So those on the outside of the plates tend to push ‘em together. Simple really although physicists had to wait until 1996 to measure it for real.

Now they can’t get away from it. One reason why microelectromechanical devices have been slow to permeate our lives is because the Casimir force tends to jam ‘n’ glue the mechanism, and that’s been a-spoilin and a-wreckin’ the party.

What these microengineers need, of course, is a way of getting rid of the Casimir force, or at least a way of balancing it out with another force in the opposite direction.

And now it looks as if they got one. Francesco Intravaia and a pal at Potsdam University in Germany say that making the plates outta a particular combination of metamaterials does the trick, turning the Casimir force from an attractive one into a repulsive force. In particular, one of the plates must be a dielectric while the other is permeable, which could be achieved by engineering them on the nanometre scale, says Intravaia.

So that could make possible a whole new generation of micromachines, with stick free parts and goodness knows what kinda hoverin’ and floatin’.

But the Potsdam work is strictly theoretical. So who’s gonna pull off this trick for real? My money’s on Vlad Shalaev at Purdue although ya’d be a fool to rule out David Smith at Duke. But there are plenty o’ dark horses in this field. Anybody got any inside knowledge they’d care to share?

Ref: arxiv.org/abs/0711.0655: Casimir Intereaction between Absorbing and Metamaterials

One Response to “The hunt for a repulsive Casimir force”

  1. ben says:

    your blog style is friggin hilarious.

    i hope you don’t get fired.