A Question for Cjlr
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11-09-2015, 02:01 PM
A Question for Cjlr
In a thread that died out a long time ago, you said.

(11-11-2013 05:07 PM)cjlr Wrote:  According to our current understanding, there is no possible way for these two exact values to coexist (the electron quite literally cannot have simultaneously well-defined spin in multiple axes). Which is to say, non-commuting operators imply an uncertainty relation. This is The Famous Uncertainty Principle (and it often gets Heisenberg's name attached to it).

The bolding is mine.

Now the electron not having simultaneously well defined spin in multiple axes.....does this apply only to 3 spatial dimensions? Suppose like string theory suggest there are more than 3 spatial dimensions, couldn't the electron have well defined spin in multiple axes?
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11-09-2015, 02:23 PM
RE: A Question for Cjlr
(11-09-2015 02:01 PM)Heywood Jahblome Wrote:  In a thread that died out a long time ago, you said.

(11-11-2013 05:07 PM)cjlr Wrote:  According to our current understanding, there is no possible way for these two exact values to coexist (the electron quite literally cannot have simultaneously well-defined spin in multiple axes). Which is to say, non-commuting operators imply an uncertainty relation. This is The Famous Uncertainty Principle (and it often gets Heisenberg's name attached to it).

The bolding is mine.

Now the electron not having simultaneously well defined spin in multiple axes.....does this apply only to 3 spatial dimensions? Suppose like string theory suggest there are more than 3 spatial dimensions, couldn't the electron have well defined spin in multiple axes?

The question is ill-conceived and pointless.

If current scientific theories are valid, then it cannot. If instead we make up whatever supplementary theories we like, anything is possible.

The gap behind that if can still fit any god you like.

...

In any case the extra dimensions posited by various current string theories do not apply to objects like electrons. So they would not matter. You're free to introduce additional elements that would, but if your sole motivation is feels and they're unfalsifiable by design, why bother?

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11-09-2015, 08:20 PM
RE: A Question for Cjlr
(11-09-2015 02:23 PM)cjlr Wrote:  
(11-09-2015 02:01 PM)Heywood Jahblome Wrote:  In a thread that died out a long time ago, you said.


The bolding is mine.

Now the electron not having simultaneously well defined spin in multiple axes.....does this apply only to 3 spatial dimensions? Suppose like string theory suggest there are more than 3 spatial dimensions, couldn't the electron have well defined spin in multiple axes?

The question is ill-conceived and pointless.

If current scientific theories are valid, then it cannot. If instead we make up whatever supplementary theories we like, anything is possible.

The gap behind that if can still fit any god you like.

...

In any case the extra dimensions posited by various current string theories do not apply to objects like electrons. So they would not matter. You're free to introduce additional elements that would, but if your sole motivation is feels and they're unfalsifiable by design, why bother?

This isn't a thread about God. I simply had a question after reading one of your old posts and decided to pick your brain about it.

In space that has 3 spatial dimensions, a dust cloud will collapse to a disc. Why? because even though all the particles are moving in a way that appears haphazardly, it you took all those motion you could determine an average spin for the cloud. What happens is the particles moving up, collide with the particles moving down and their motions cancel each other out.

Now suppose you had 4 spatial dimensions instead of 3. Would dust clouds still have an average spin? Actually they would have two average spins. In 4 spatial dimension space dust clouds would not collapse into discs. Now if a dust cloud in 4D can have 2 average spins, why can't an electron? I understand that electron spin is not the same as dust cloud spin. Your answer is that even if their were 4 spatial dimensions an electron can still only have well defined spin along one axis. Fair enough, I'm not going to dispute you on it.
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12-09-2015, 12:58 AM
RE: A Question for Cjlr
(11-09-2015 08:20 PM)Heywood Jahblome Wrote:  In space that has 3 spatial dimensions, a dust cloud will collapse to a disc. Why? because even though all the particles are moving in a way that appears haphazardly, it you took all those motion you could determine an average spin for the cloud. What happens is the particles moving up, collide with the particles moving down and their motions cancel each other out.

You could determine "spin", by which you really mean aggregate angular momentum, yes.
(note that this is a classical description)

(11-09-2015 08:20 PM)Heywood Jahblome Wrote:  Now suppose you had 4 spatial dimensions instead of 3. Would dust clouds still have an average spin? Actually they would have two average spins.

Would they? I'd like to see how you conclude this...

The axis of rotation is defined according to the average of momenta. Four dimensions still give a single average. So do two. Or N.

It isn't as mathematically simple as merely saying "assume 4 dimensions", though, for constructing a problem. The operations within that framework - the tools required to analyse the physics - are not as simply generalised and do not necessarily have much physical correspondence to their 3 dimensional counterparts.

(11-09-2015 08:20 PM)Heywood Jahblome Wrote:  In 4 spatial dimension space dust clouds would not collapse into discs. Now if a dust cloud in 4D can have 2 average spins, why can't an electron? I understand that electron spin is not the same as dust cloud spin.

If X is not Y, then constructing scenarios for Y does not in any way model X. Electrons - and other quantum objects - don't "spin" as macroscopic classical entities do.

(11-09-2015 08:20 PM)Heywood Jahblome Wrote:  Your answer is that even if their were 4 spatial dimensions an electron can still only have well defined spin along one axis. Fair enough, I'm not going to dispute you on it.

Because the extra dimensions posited by string theories are not comparable to the macroscopic 3+1 we normally interact with, and because the spin angular momentum of quantum objects can actually be generalised to higher dimensionality, never mind that that isn't what string theories suggest, and when that is done, it's still a matter of single basis states being formed of superpositions of their non-commuting orthogonal counterparts.

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12-09-2015, 03:08 AM
RE: A Question for Cjlr
(12-09-2015 12:58 AM)cjlr Wrote:  
(11-09-2015 08:20 PM)Heywood Jahblome Wrote:  Now suppose you had 4 spatial dimensions instead of 3. Would dust clouds still have an average spin? Actually they would have two average spins.

Would they? I'd like to see how you conclude this...

Not sure where I came across it but it does make sense intuitively.

In 2D space spin would be around a point. In 3D space spin would be around a line(axis). In 4D space spin would be around a planes. Spin or Rotation is really just transferring motion from one direction to another.....X into Y for instance. In 4D you could transfer motion from X to Y, X to Z, X to W, Y to Z, Y to W, and W to Z. Transferring motion from X to Y, doesn't preclude transferring motion to W to Z.....hence you can have two spins in 4D space.
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14-09-2015, 02:26 PM
RE: A Question for Cjlr
(12-09-2015 03:08 AM)Heywood Jahblome Wrote:  
(12-09-2015 12:58 AM)cjlr Wrote:  Would they? I'd like to see how you conclude this...

Not sure where I came across it but it does make sense intuitively.

"Making sense intuitively" is a shittacularly godawful way of coming to a real understanding of modern physics.
(or math)

(12-09-2015 03:08 AM)Heywood Jahblome Wrote:  In 2D space spin would be around a point. In 3D space spin would be around a line(axis). In 4D space spin would be around a planes. Spin or Rotation is really just transferring motion from one direction to another.....X into Y for instance. In 4D you could transfer motion from X to Y, X to Z, X to W, Y to Z, Y to W, and W to Z. Transferring motion from X to Y, doesn't preclude transferring motion to W to Z.....hence you can have two spins in 4D space.

Spin refers to angular motion about a single axis. That's how it's defined - it can't be anything else.

If you are instead referring to harmonic motion, then that's different. Harmonic motion may be arbitrarily one to N-dimensional. You can easily have "two spins" (note: not really spins) for three-dimensional objects as well - at least mathematically; physical situations are limited to the constraints of what real forces exist. Harmonic motion in two dimensions generates either an ellipse or a figure-eight, but obviously an orbit does not include the latter as a valid solution. Likewise for 3+. To describe the Earth's rotation, a single axis is not sufficient; the Earth spins about an axis but the axis is not fixed - it, too, oscillates.

And regardless, that is not how quantum spin behaves, because that is a classical description of motion. The name is a holdover from an analogy. An extension from three to four dimensions simply adds a fourth orthogonal basis vector - it does not meaningfully change the resulting behaviour.

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14-09-2015, 04:02 PM
RE: A Question for Cjlr
(14-09-2015 02:26 PM)cjlr Wrote:  
(12-09-2015 03:08 AM)Heywood Jahblome Wrote:  Not sure where I came across it but it does make sense intuitively.

"Making sense intuitively" is a shittacularly godawful way of coming to a real understanding of modern physics.
(or math)

(12-09-2015 03:08 AM)Heywood Jahblome Wrote:  In 2D space spin would be around a point. In 3D space spin would be around a line(axis). In 4D space spin would be around a planes. Spin or Rotation is really just transferring motion from one direction to another.....X into Y for instance. In 4D you could transfer motion from X to Y, X to Z, X to W, Y to Z, Y to W, and W to Z. Transferring motion from X to Y, doesn't preclude transferring motion to W to Z.....hence you can have two spins in 4D space.

Spin refers to angular motion about a single axis. That's how it's defined - it can't be anything else.

If you are instead referring to harmonic motion, then that's different. Harmonic motion may be arbitrarily one to N-dimensional. You can easily have "two spins" (note: not really spins) for three-dimensional objects as well - at least mathematically; physical situations are limited to the constraints of what real forces exist. Harmonic motion in two dimensions generates either an ellipse or a figure-eight, but obviously an orbit does not include the latter as a valid solution. Likewise for 3+. To describe the Earth's rotation, a single axis is not sufficient; the Earth spins about an axis but the axis is not fixed - it, too, oscillates.

And regardless, that is not how quantum spin behaves, because that is a classical description of motion. The name is a holdover from an analogy. An extension from three to four dimensions simply adds a fourth orthogonal basis vector - it does not meaningfully change the resulting behaviour.

If the magnetogyric ratio of the electron was fine tuned........then god. Facepalm

"If we are honest—and scientists have to be—we must admit that religion is a jumble of false assertions, with no basis in reality.
The very idea of God is a product of the human imagination."
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16-09-2015, 12:28 AM
RE: A Question for Cjlr
(14-09-2015 04:02 PM)The Organic Chemist Wrote:  If the magnetogyric ratio of the electron was fine tuned........then god. Facepalm

This thread isn't about God. Please be quiet and let the adults talk.....thanks.
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16-09-2015, 12:53 AM
RE: A Question for Cjlr
(16-09-2015 12:28 AM)Heywood Jahblome Wrote:  
(14-09-2015 04:02 PM)The Organic Chemist Wrote:  If the magnetogyric ratio of the electron was fine tuned........then god. Facepalm

This thread isn't about God. Please be quiet and let the adults talk.....thanks.

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16-09-2015, 02:19 AM
RE: A Question for Cjlr
(14-09-2015 02:26 PM)cjlr Wrote:  Spin refers to angular motion about a single axis. That's how it's defined - it can't be anything else.

In 4D space two independent rotations can occur without them summing to a single rotation in a single plane. An Object rotating in the XY plane can also simultaneously rotate in the WZ plane. The rotation in the XY plane is around an axis which is a straight line, and the rotation around the WZ plane is around another axis which is also a straight line. A dust cloud in 4D space wouldn't collapse into a single accretion disc because there isn't a single plane of rotation. There are two planes of rotation....each having its own axis.

I think I am good here.
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