Dimensions of Particles

Singularitarian said:
These odd properties by the way, where essential because yet again i explain, pointlike particles do not possess a true 360 degree back-to-orientation reality; non-pointlike particles can have a real axial spin.
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Classical pointlike particles can't have a spin at all, much less half-integer spin. And classical particles of any shape/size whatsoever cannot have the 720-degree rotation behavior. If you view this behavior as a problem, extending the size of the particle doesn't fix it. Making the particle quantum-mechanical does fix it.
 
Ziggurat can help me out here, but applying classical spin to elementary particles has other problems, iirc, you run into serious issues with time dilation. A particle with classical spin would spin slower as it approaches the speed of light from the POV of a stationary observer.
 
Singularitarian said:

How does one interpret noninteger spin for a multidimensional quantum particle as classical angular momentum without running into the relativistic problems Dorfl pointed out?

Dorfl never pointed that out.
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This is what Dorfl wrote:
Dorfl said:
If I remember correctly, isn't it fairly easy to demonstrate that quantum spin cannot be due to actual rotation of a particle, because that would require most particles to rotate faster than light to match observations?
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So, yes he did. Is there anyone other than Singularitarian who doesn't see that?


Oh, and please nest your quotes.
 
Ben and Mr D,

what you said Mr D was

''How does one interpret noninteger spin for a multidimensional quantum particle as classical angular momentum without running into the relativistic problems Dorfl pointed out?''

Dorfl said

'' If I remember correctly, isn't it fairly easy to demonstrate that quantum spin cannot be due to actual rotation of a particle, because that would require most particles to rotate faster than light to match observations? ''

What Dorfl is referring to is the orietational spin, where it would need to exceed lightspeed, when it is a pointlike particle. You are referring to angular momentum as if the dimensional object would continue to exhibit problems with spin. The problems only arise from non-dimensional particle.

So, no... not what Dorfl said at all.
 
RussDill said:
Ziggurat can help me out here, but applying classical spin to elementary particles has other problems, iirc, you run into serious issues with time dilation. A particle with classical spin would spin slower as it approaches the speed of light from the POV of a stationary observer.
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The spin has its own spin-contraction formula. I will try and find it for you.
 
Singularitarian said:
These odd properties by the way, where essential because yet again i explain, pointlike particles do not possess a true 360 degree back-to-orientation reality; non-pointlike particles can have a real axial spin.
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Sigh.

Unless these non-pointlike particles you speak of do not obey relativity (which to be fair, you hinted at with your "currently not allowed" comment), the angular momentum they carry as "spin" cannot be classical angular momentum. And if your proposed non-pointlike particles do no obey relativity, then how do you justify applying fluid dynamics to them?

The intrinsic angular momentum of fermions in the Standard Model is part-and-parcel of the Standard Model - it is entirely self-consistent and matches very well to experimental measurements.

If you're going to try to remodel Standard Model with nonpointlike electrons etc, you're going to have throw it all out and your model must also explain (among other things), the magnetic moment of the electron, the width of atomic spectra emissions, the interference patterns of electron beams in the double-slit experiment and so on. So far you haven't even justified why the Standard Model is insufficient other than some vague notion that "Having some kind of dimension to them though, has great advantages"
 
That's funny that, because, there was no problems with a classical view of spin, until that is, we realized that quantization of pointlike particles did not allow the true three-dimensional rotational spin, according to Cramer. In fact, he hints at no errors with relativity in general before such a quantization was made, so i think you are wrong.
 
RussDill said:
...And if you claimed that it applies to electrons, photons, and quarks, wouldn't that prove my point?
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I could attempt to answer any problems which may arise with having the relativistic effects taken into account, but these would be guesses, educated ones though. For instance, spin may seem altered from our perspective, but inertially from the view of an electron, it would remain exactly the same, according to relativity.
 
Singularitarian said:
That's funny that, because, there was no problems with a classical view of spin, until that is, we realized that quantization of pointlike particles did not allow the true three-dimensional rotational spin, according to Cramer. In fact, he hints at no errors with relativity in general before such a quantization was made, so i think you are wrong.
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ORLY? Is that what you will stick with? Please consider the ramifications of a photon with classical spin.
 
RussDill said:
Ziggurat can help me out here, but applying classical spin to elementary particles has other problems, iirc, you run into serious issues with time dilation. A particle with classical spin would spin slower as it approaches the speed of light from the POV of a stationary observer.
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Rotation in relativity is a little messy, so that's not quite true. But there are indeed very big problems with trying to treat electron spin as classical. The whole rotating faster than light speed bit is one of the problems. Rigidity of the electron is another. Then there's the whole problem of the gyromagnetic ratio, which is very unclassical.
 
Singularitarian said:
What Dorfl is referring to is the orietational spin, where it would need to exceed lightspeed, when it is a pointlike particle. You are referring to angular momentum as if the dimensional object would continue to exhibit problems with spin. The problems only arise from non-dimensional particle.
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No.

What Dorfl is referring to is the very well known problem of treating electrons like physical nonpointlike particles.


Try it (At most this should take 20 minutes - if your google-fu is particularly weak):

Look up the mass of an electron and google up the current experimental upper bounds on the size of an electron.

Come up with a physical mass distribution for your proposed nonpointlike model - any one you like - along with its moment. Then calculate how fast your model must spin for it to have classical angular momentum 1/2.

Post the model and the formula here.
 
RussDill said:
Are you claiming that fermions have dimensions and bosons are pointlike?
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No. I am saying in this demonstration, i have investigated the spin problem of electrons, a rule which gave rise to the quantized angular momentum, which goes for all fermions. I have never gone as far as to speculate about the other class.
 
Singularitarian said:
No. I am saying in this demonstration, i have investigated the spin problem of electrons, a rule which gave rise to the quantized angular momentum, which goes for all fermions. I have never gone as far as to speculate about the other class.
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What problem are you trying to overcome? Is there some experimental data that is not matching up with the standard model?
 
I see it this way. A point has no dimensions and exists only in the realm of math. Ditto for a line and a plane the first two "plane. If it is an atom thick it is a slab not a plane with no volume or a line with no thickness. Volume is what makes our universe. No volume no matter. Now imagine a volume in the form of a sphere, the center of which is at point 0,0 on a graph. If you spin that sphere around that point it is another dimension of the sphere. If you spin it counterclockwise versus clockwise that may be defined as a dimension too, but maybe just spin itself is. Now you can give that sphere velocity by giving it a constant motion away from that 0, 0 coordinate and that is another, give it acceleration and jerk and you have 2 more. In other words motion using powers of time are dimensions just as powers of lengths are.
 
Singularitarian said:
I just have a conceptual problem with zero-dimensional particles, that is all :(
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And I'm the one with the attitude? Sheesh. :rolleyes:

Do you think you might have gotten a friendlier response if you started with the above statement and started asking questions about the Standard Model?

Is there anything about the Cohen paper that you'd like to discuss with regards to the pointlike nature of particles?
 
Tumbleweed said:
I see it this way. A point has no dimensions and exists only in the realm of math. Ditto for a line and a plane the first two "plane".
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Why?

(And per the rest of the comment, the idea of assigning different states and properties of a system to dimensions of some space is very common in modern physics)
 
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