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An electron scanning microscope image of the University of Florida's Casimir force testing metal fin plate. Bizarre geometry may help prevent the quantum force from interfering with the ever-shrinking world of electronics.  (Source: Yiliang Bao and Jie Zoue/University of Florida)
"Gotta keep 'em separated."

Quantum physics isn't a very disciplined place. Bizarre things tend to happen as scientists peer deeply into the smaller and smaller worlds afforded by advancing technology. One such weak quantum force, known as the Casimir force, named for the origin of its predicted effect, Hendrik Casimir, is currently under scrutiny by University of Florida researchers.

When two objects are placed extremely close together, they will be attracted to each other by this only recently proven to exist quantum force. Instead of the objects' masses pulling them together, Casimir force works as an external force, almost like hydrodynamic pressure.

In this case, the empty space between the two objects isn't actually empty. All space is filled with electromagnetic fields and the virtual particles associated with them. These particles, in quantum physics, also exist as waves, and here's where things start to make sense. Around the objects, these particle/waves can be of any varying wavelength, but only a smaller number of shorter wavelength particles can fit between them. This creates a sort of low versus high pressure system where the force of the “heavier” longer wavelength particles acts to push the masses together.

UF's research into this interesting force may, in the future, help the ever growing miniaturization of electronic components. As MEMS (microelectricalmechanical) devices get smaller and stacked closer together, the likelihood of the Casimir force becoming a problem gets larger. “Stiction” is already a problem in super-fine structure assembly, and though it can be caused by a number of variables, the Casimir force can easily contribute to it.

In a paper published in Physical Review Letters, lead-author Ho Bun Chan explains, “We are not talking about an immediate application, we are talking about, if the devices continue to be smaller and smaller, as the trend of miniaturization occurs, then the quantum effects could come into play.”

With integrated circuits and other electronic parts rapidly losing size but gaining parts and complexity, these effects could easily occur in the next decade.

To study how Casimir force can be affected by structure, the UF team created a metal panel resembling a fin radiator, with fin structures of approximately 200nm separated by the same distance. This effectively cut the gapped surface area in half compared to two flat plates that were used as a control. They found that, though having more area between the plates for longer wavelength particles to occupy and half the accessible surface area, the comb-like structure only reduced Casimir force by 30 to 40 percent.

While the experiment didn't show the expected 50 percent reduction, it helped prove that, instead, the strength of the Casimir force depends on the geometry of the objects in question. This may be useful in the future for MEMS and other nanomachinery engineers as they need to design nanoscopic parts that would not work well if they were heavily affected by the mysterious quantum particles.



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Minor correction
By masher2 (blog) on 7/18/2008 10:37:14 AM , Rating: 1
> "When two objects are placed extremely close together, they will be attracted to each other by this only recently proven to exist quantum force..."

Actually, the Casimir effect can be attractive or repulsive, depending on the particular geometry of the situation.

> "but only a smaller number of shorter wavelength particles can fit between them. This creates a sort of low versus high pressure system where the force of the “heavier” longer wavelength particles acts to push the masses together..."

The Casimir Effect is better understood as a consequence of quantum fluctuations in a vacuum. Though a vacuum appears to be empty, the space is actually filled with a vast array of "virtual" particles winking in and out of existence. Normally their total effect is zero, as all the random events cancel each other out.

The effect occurs when a particular configuration (of two very close parallel plates, say) reinforces a particular mode or set of modes, so that the fluctuations don't cancel each other out, generating a net force.

The Casimir Effect is truly an only partly-understood "spooky stuff" component of QM, and has been proposed as an eventual means for generating things like hyperdrives and wormholes.




RE: Minor correction
By William Gaatjes on 7/18/2008 2:24:35 PM , Rating: 2
Me lost in my thoughts :

Hooray, I never liked the standard model because it raises more questions then it gives answers. And i always had the feeling there must be some medium. Way back at school me and another young guy where always battering the physics teacher with these questions. For example : How can a elektromagnetic wave propagate trough vacuum. He would always say that it is because it also has a particle nature.

I always believed that their is no such thing as particles. Particles are just effects of some cause we don't fully understand yet.
I predict :

If you look at the spectrum and go beyond gamma rayes you will get what we know as solid matter ?


RE: Minor correction
By mars777 on 7/19/2008 8:19:01 AM , Rating: 2
You could read this if you are interested:

http://en.wikipedia.org/wiki/String_theory

In the theory of strings strings are the cause of waves and particles, depending on their "configuration" (just to be short).


RE: Minor correction
By William Gaatjes on 7/20/2008 4:55:06 AM , Rating: 2
I know that theory and i feel it has more truth to it. But last time i read about it they already start to come with the same problems the standard model has. Too many different strings. Although i have lot's of faith in Edward Witten.

I would believe more that the particles and the energy we experience are some how similair as what we would find in rf circuits or common audio. Peaks, falls, sum frequencies, subtracted frequencies. Combine it all and in at least a 3d plane.

Just like Michael wrote above. Popping in and out into "our"
existence or should i say dimension.

I have 1 more crazy thought :

I have always understood that elektromagnetism is a combined
elektric field and magnetic field. These are coupled.
But is there a phase difference ? Can there be a phase difference ?

How about gravity being the phase difference between the electric force and the magnetic force from elektromagnetism ?

Lot's of questions and no answers...

Alas...


RE: Minor correction
By Smartless on 7/18/2008 3:20:50 PM , Rating: 4
What the heck do you do for a day job? Sheeesh.


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