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Author Topic: What is the Casimir force?  (Read 4108 times)

Offline jaiii

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What is the Casimir force?
« on: 26/02/2011 17:32:11 »
Hi,
I knew ,this question is a little strange.
Create a negative energy when the distance between the metal plates will be more than 1 mm?
Thank
« Last Edit: 26/02/2011 20:35:59 by chris »


 

Offline yor_on

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Re: What is the Casimir force?
« Reply #1 on: 26/02/2011 18:35:16 »
"One of the early Casimir experiments [3] using the sphere and flat plate geometry measured the Casimir force in the 0.6 –6 um range. The sphere was a 4 cm diameter spherical lens and the flat plate was a 2.5 cm diameter optical flat, the optical surfaces Cu coated with a top Au coating. A noticeable change in the Casimir force was not found until the gap between the sphere and flat plate reached the 0.6 um lower limit. More recently, the Casimir force was determined [4] with an atomic force microscope using an Au coated sphere about 200 um in diameter and a flat plate. The Casimir force Fc was measured from 0.1 to 0.9 mm and corrected for plasmon frequency, roughness of the surface, and finite temperature. The Casimir force was found to only noticeably change at separations below about 0.2 um. In [5] a Cr coated polysilicon plate topped with Au coating was suspended on a torsion rod. A similarly coated 200 um diameter sphere was placed off the torsion axis, the Casimir force between the sphere and plate causing a torque to rotate the plate. The Casimir force was measured over a range 0.1 – 1 um with the force noticeably beginning to increase at about 0.2 um. Generally, the gap d < 0.2 um for the Casimir force to be significant."

micrometer (um) = 0.000001 m (1 X 10-6 m)

And what it 'works from' is 'virtual particles'. Those elusive wavelengths 'not being there'. "According to the quantum theory, the vacuum contains virtual particles which are in a continuous state of fluctuation. Casimir realised that between two plates, only those virtual photons whose wavelengths fit a whole number of times into the gap should be counted when calculating the vacuum energy.  The energy density decreases as the plates are moved closer, which implies that there is a small force drawing them together."

"When the vacuum is bounded by a pair of conducting surfaces, the only electromagnetic waves that can exist are those with wavelengths shorter than the distance between the surfaces. The exclusion of the longer wavelengths results in a tiny force between the conductors..You have to add up the momentums of all the wavelengths of virtual particles which are smaller than the distance between the plates, and subtract that from the background particles...

Inside the plate, the wavelengths must be integral values as per quantum physics, and these must be smaller than L. To get the net outside force, you simply take the normal vacuum E-M tensor and exclude the ones inside the plates, i.e. subtracting a negative more or less. In other words, excluding the inside ones gives you the outside, excluding the outside values gives you the inside values, and the wavelengths that can fit in L must follow L/n where n is the set of {positive} integers."

Casimir force. To get it 'working' at distances more than one mm? Don't think so myself..
 

Offline jaiii

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Re: What is the Casimir force?
« Reply #2 on: 26/02/2011 19:54:02 »
Thank veri much.
 

Offline lightarrow

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What is the Casimir force?
« Reply #3 on: 26/02/2011 22:19:40 »
Virtual particles are not needed to explain the Casimir force.
 

Offline yor_on

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What is the Casimir force?
« Reply #4 on: 27/02/2011 12:26:47 »
Ok I'll bite :)
How would you explain it Lightarrow?
 

Offline jaiii

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What is the Casimir force?
« Reply #5 on: 27/02/2011 15:14:36 »
Ok I'll bite :)
How would you explain it Lightarrow?

I am sorry but I dont understand.
« Last Edit: 27/02/2011 15:16:28 by jaiii »
 

Offline flr

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What is the Casimir force?
« Reply #6 on: 27/02/2011 15:39:02 »
Virtual particles are not needed to explain the Casimir force.

Could you describe such an explanation that does not require virtual particles? Or a link.
 

Offline jaiii

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What is the Casimir force?
« Reply #7 on: 27/02/2011 17:27:51 »
I never say that.
Could answer my questions pleasse?
 
Thank veri much.
« Last Edit: 27/02/2011 17:29:43 by jaiii »
 

Offline lightarrow

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What is the Casimir force?
« Reply #8 on: 27/02/2011 19:52:59 »
Ok I'll bite :)
How would you explain it Lightarrow?


http://en.wikipedia.org/wiki/Casimir_effect
Quote
Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. This force has been measured, and is a striking example of an effect purely due to second quantization.[3][4]
 

Offline yor_on

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What is the Casimir force?
« Reply #9 on: 28/02/2011 08:53:29 »
I never say that.
Could answer my questions pleasse?
 
Thank veri much.

It was as a response to Lightarrow, Jaiii, that I wrote it.
And now I'll need to look at it :) And see what I can get into that thick skull of mine..

Ahem :)
 

Offline yor_on

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What is the Casimir force?
« Reply #10 on: 28/02/2011 09:07:14 »
"The Casimir effect is intrinsically a second quantisation effect, and cannot be "reduced" to something conceptually easy for the layman. Explaining what a quantised field is in few words is even more difficult."

Nope.

"first-quantization quantum mechanics (Heisenberg’s and Schroedinger’s first-quantization quantum mechanics, uncertainty principle making the world a matter of probability) went out of the window in 1927 when Dirac’s relativistic quantum field theory replaced it.

First-quantization is a lie: it treats the Coulomb field binding the electron to the nucleus classically, so the chaos of the motion of the electron has to be falsely introduced by making the electron’s motion intrinsically indeterminate. Second-quantization, as Feynman explains, gets rid of this application of the uncertainty principle because it simply treats the Coulomb field properly as a quantum field, in which field quanta (random discrete interactions) replace the false classical smooth Coulomb field.

The electron has a chaotic motion because the quantum electromagnetic field binding it in its orbit of the nucleus is chaotic, as Feynman explains:

“I would like to put the uncertainty principle in its historical place … If you get rid of all the old-fashioned ideas and instead use the ideas that I’m explaining in these lectures – adding arrows [path amplitudes] for all the ways an event can happen – there is no need for an uncertainty principle! … When we look at photons on a large scale … there are enough paths around the path of minimum time to reinforce each other, and enough other paths to cancel each other out.

But when the space through which a photon moves becomes too small (such as the tiny holes in the screen), these rules fail … there are interferences created by the two holes, and so on. The same situation exists with electrons: when seen on a large scale, they travel like particles, on definite paths. But on a small scale, such as inside an atom, the space is so small that there is no main path, no ‘orbit’; there are all sorts of ways the electron could go, each with an amplitude. The phenomenon of interference becomes very important, and we have to sum the arrows [amplitudes for different paths] to predict where an electron is likely to be.”

- Richard P. Feynman, QED, Penguin Books, London, 1990, pp. 55-85.

Well yes, if you find quanta being the 'ultimate answer' to the universe, life and all :) Isn't it strange how every generation expect themselves to have solved the celestial motion of the infinite spheres :) and all ..

Myself I think quanta exist, but I do not expect them to answer that final question, and I also expect a 'smooth' state hiding behind that. To me quanta is just one of the emergences we see, it's a fractal universe.
« Last Edit: 28/02/2011 09:10:03 by yor_on »
 

Offline yor_on

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What is the Casimir force?
« Reply #11 on: 28/02/2011 09:14:05 »
And this make me want to puke..

"United States Patent #7,379,286 has recently been granted to Jovion Corp., which is associated with the University of Colorado, to exploit a different aspect of the Casimir effect. (See [6]). Namely, a thermal effect, by which gas passing through Casimir "strips" or "tunnels" is heated.

The Wikipedia article does not explain how the Casimir effect could have a thermal aspect like this. Can someone add this to the article please? 5 February 2009 (UTC)

Casimir effect restricts longer wavelength vacuum flucuations between 2 closely spaced conductive plates. The plates will be drawn together due to this difference in ratio of short to long vacuum flucuations between the plates VS outside the plates. If the plates are braced apart you create a permanent exclusion zone to the longer wavelength vacuum flucuations where gas atoms experience an anomalous effect broiled in controversey. Dr Mills of Black Light power coined the term "hydrino" with very specific properties outlined in his classical Grand Unified theory most controversial of which is a subzero state orbital. Professor Moddel and Bernard Haisch do not describes a hydrino as defined by Dr Mills; Their SED based theory describes different properties and the way they arrive at it is very different but they also describe an atom that "spins down" below zero state. I contend that the orbital is not subzero but rather temporal axis displacement as already suggested by Professor Jan Naudts in wikipedias hydrino controversey timeline. My only contribution to his suggestion is that a covalent bond is essential to "lock" orbital orientation while inside the exclusion to turn the covalent orbitals into a bucket that forces chaotic Vacuum flux to accumulate organized boundaries as the new molecule tries to exit and finally causes the bond to fail releasing the signature black light plasma as nature restores the atoms to mon atomic energy levels. theoretically the heat could keep the atoms disassociated and the procedure could repeat endlessly supported by the statistical proportion of atoms reforming as H2 while inside an exclusion field Vs outside - Thermally this may actually be a balancing act to prevent the cavities from overheating and melting closed."

I want to patent gravity..
And thought..

I know I can do that in the States..
Sh*.
==

And, your genes :)
Awh, seems I'm too late on that one..

But thought is still open, isn't it?
I can always patent the universe though?

Patents, your new way of living.. (You know, sometimes the game-rules we humans make each other play by becomes just too stupid for thought. The American way of contending all foreign patents at the same time as they think it possible to patent stuff like genes, the Casimir effect, etc. It's getting to be a cosmic joke, with humanity going out in war on who 'own' what 'constant' 'gene' whatever. We're copy cats, not inventors. But those greedy will always look for 'new angles'.)
« Last Edit: 28/02/2011 09:33:12 by yor_on »
 

Offline jaiii

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What is the Casimir force?
« Reply #12 on: 28/02/2011 10:00:14 »
Yes thank veri interesting.I see it an try search in internet.
 

Offline lightarrow

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What is the Casimir force?
« Reply #13 on: 28/02/2011 12:38:11 »
And this make me want to puke..

"United States Patent #7,379,286 has recently been granted to Jovion Corp., which is associated with the University of Colorado, to exploit a different aspect of the Casimir effect. (See [6]). Namely, a thermal effect, by which gas passing through Casimir "strips" or "tunnels" is heated.

The Wikipedia article does not explain how the Casimir effect could have a thermal aspect like this. Can someone add this to the article please? 5 February 2009 (UTC)

Casimir effect restricts longer wavelength vacuum flucuations between 2 closely spaced conductive plates. The plates will be drawn together due to this difference in ratio of short to long vacuum flucuations between the plates VS outside the plates. If the plates are braced apart you create a permanent exclusion zone to the longer wavelength vacuum flucuations where gas atoms experience an anomalous effect broiled in controversey. Dr Mills of Black Light power coined the term "hydrino" with very specific properties outlined in his classical Grand Unified theory most controversial of which is a subzero state orbital. Professor Moddel and Bernard Haisch do not describes a hydrino as defined by Dr Mills; Their SED based theory describes different properties and the way they arrive at it is very different but they also describe an atom that "spins down" below zero state. I contend that the orbital is not subzero but rather temporal axis displacement as already suggested by Professor Jan Naudts in wikipedias hydrino controversey timeline. My only contribution to his suggestion is that a covalent bond is essential to "lock" orbital orientation while inside the exclusion to turn the covalent orbitals into a bucket that forces chaotic Vacuum flux to accumulate organized boundaries as the new molecule tries to exit and finally causes the bond to fail releasing the signature black light plasma as nature restores the atoms to mon atomic energy levels. theoretically the heat could keep the atoms disassociated and the procedure could repeat endlessly supported by the statistical proportion of atoms reforming as H2 while inside an exclusion field Vs outside - Thermally this may actually be a balancing act to prevent the cavities from overheating and melting closed."

I want to patent gravity..
And thought..

I know I can do that in the States..
Sh*.
==

And, your genes :)
Awh, seems I'm too late on that one..

But thought is still open, isn't it?
I can always patent the universe though?

Patents, your new way of living.. (You know, sometimes the game-rules we humans make each other play by becomes just too stupid for thought. The American way of contending all foreign patents at the same time as they think it possible to patent stuff like genes, the Casimir effect, etc. It's getting to be a cosmic joke, with humanity going out in war on who 'own' what 'constant' 'gene' whatever. We're copy cats, not inventors. But those greedy will always look for 'new angles'.)
The "Hydrino" doesn't exist. It's one of those things that in this ng would be put in the "New theories" section (to be kind...).
His proponent is one of those who wants to make money with the idea of cold fusion (which would be "explained" with the hydrino theory).
 

Offline yor_on

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What is the Casimir force?
« Reply #14 on: 28/02/2011 17:48:46 »
That one just followed as it seemed a comment on that patent. I didn't consider it actually, that whole post is just about one thing. The folly of patenting theoretical science. Had Einstein lived, do you think he would have tried to patent the theory of relativity? To me it seems incredulous, normally I don't react like this but it seemed to reach some sort of limit with me :)

But I'm calmer now..
 

Offline jaiii

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What is the Casimir force?
« Reply #15 on: 28/02/2011 18:32:08 »
Patent what do I want.
But if it's true is another story.
 

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What is the Casimir force?
« Reply #15 on: 28/02/2011 18:32:08 »

 

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