Ultima Thule

In ancient times the northernmost region of the habitable world - hence, any distant, unknown or mysterious land.

Friday, November 03, 2006

A Casimir force for good in MEMS design

By Aussiegirl

Now this is very interesting. I read about the zero-point field and its relation to the Casimir force in Bernard Haisch's new book, "The God Theory". He has done some groundbreaking work on the zero-point field that points to some intriguing possibilities that may include mystical and religious ones. I highly recommend the book, by the way. I will be doing a list of recent readings shortly that will include short reviews of a number of books I've found interesting over the last year or so.

A Casimir force for good in MEMS design (November 2006) - News - PhysicsWeb

Researchers in the US and Russia have demonstrated that the Casimir force between two conducting surfaces can be controlled by modifying the density of charge-carrying particles within the surfaces. The result could have positive implications for the design of novel microelectromechanical systems, or MEMS (Phys Rev Lett 97 170402).

The mysterious attraction between two neutral, conducting surfaces in a vacuum was first described in 1948 by Henrik Casimir and cannot be explained by classical physics. Instead it is a purely quantum effect involving the zero-point oscillations of the electromagnetic field surrounding the surfaces. These fluctuations exert a "radiation pressure" on the surfaces and the overall force is weaker in the gap between the surfaces than elsewhere, drawing the surfaces together.

The Casimir force can be both a help and a hindrance in the design of the micrometre-scale mechanical components used in MEMS. It can cause trouble by causing components to stick to one another, but it has also been exploited to control the movement of conducting plates in MEMS devices. As a result, the precise control of the Casimir force would be an important tool for MEMS designers.

Now Umar Mohideen of the University of California, Riverside and colleagues have made an important step towards Casimir control by demonstrating that materials with higher charge-carrier densities are subject to greater Casimir forces than those with lower densities.


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