Quantum statistics of angular momentum

He may just be a good-natured fellow who likes discussion even when it is highly critical of what he says - a sort of thinking man's Wellwisher.

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Teaching is hard work. ALL of your students will be just like me, and that will be true no matter whether you actually are teaching them anything that is either true or useful or not. The only difference is, this student actually DOES understand the teacher's limitations. No doubt, a lot of teachers won't like that, even a little bit.

Baffle someone/somewhere else wth the BS you call "science". I learned it from the teachers of your teachers. Humanity is about as smart as owl excrement, and it has been that way for longer than any of them can even remember, and they rarely do, because it isn't part of the curriculum. If you don't know or remember your limitations, nature will be more than happy to teach them to you again. Work them out with math to twelve significant digits before the next extinction event, whenever that might come. Or assign it as homework to your students. A fresh start at a problem is always part of nature's lesson plans, even if it was never part of yours.

I'm not as religious a person as Wellwisher, but at least I understand my limitations. Do you?

 

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What a strange and rambling reply. Have you finally run up the Jolly Roger as a nutter?

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I'm not sure any of us really understand our limitations. A lot of the time I am told I could (and by implication, should) do more than I think I can.

And I don't understand what has brought on this tirade about teaching and bullshit. I'm not teacher - though I do try occasionally to teach on this forum on subjects where I can do so with confidence. I was always taught, and I firmly believe (and in fact I frequently emphasise in the course of discussions here), that all we have in science are imperfect models of reality. However, that being said, the models we now have are the best humanity has ever had and they have been hard won by being tested and sifted out from a dross of nonsense and wrong turnings taken by Man down the ages. So they have a lot more going for them than someone making things up or just speculating.

 

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And that assessment, like everything else, is a matter of opinion. I'm not Wellwisher. I know science is always a work in progress, and that it is tough. It's even harder if you either don't have an open mind, or are just ignorant, which amounts to the same thing.

If your methods are inconsistent, or produce results that are, work on THOSE until they are less so. Don't keep on teaching inconsistent methods as if they were fact, or etched in stone or something. Don't think it was easy for me, deconstructing the garbage I was taught. Your kids will learn it the same way, and you will pay for someone to teach them that. If that's what you want, fine by me. Nature has a way of sorting such things out, but it isn't always pretty or elegant.

 

Like, for example, if someone keeps saying that redshift quantization is a thing when the best observations can't find it? It would be just like that person is shutting themselves off from the available evidence.

 

This is more rambling, but I begin to detect a theme, I think. What do you mean by "inconsistent methods"? Statistical thermodynamics, combined with QM, has proved itself amazingly powerful at accounting for all manner of things in a highly consistent way, from the width of spectral lines to the specific heats of gases or chemical kinetics. Hardly a day goes by in the mind of a physical chemist without consideration of whether ε >> kT or << kT, in some context or other, or the size of the gap between quantised energy levels that ε signifies. There is certainly a bit of a loose end around what exactly quantum "spin" is, but the beauty of a successful theory is that you can use it while isolating the loose ends to areas that do not invalidate its application in practice.

But it is all still a model and if you are well taught (perhaps you were taught badly?), that is also what you will be taught about it. We will always have some loose ends until we have perfect models, at which point presumably science will stop, because there will be nothing further to explain. (I don't believe we will ever will reach that point.) But you seem to be railing against the teaching of science as if the fact that the models are imperfect makes teaching it at all a poisonous act of indoctrination. That is just silly.

However, if I were to be given unlimited power over science curricula at universities, I would make some study of the history of science mandatory. That I think is where one gets the right perspective on the triumphs and disasters and how history can re-appraise forgotten thinkers. (I am reading about Robert Hooke at the moment.)

 

I was taught well in high school, and badly in college. As far as education goes, you don't get what you paid for. Worse, by the time you have figured that out, it's too late.

I would have been better off with chemistry!

 

I should probably stop reading stuff like this:

http://www.holoscience.com/wp/synopsis/

which is associated with this:

https://en.wikipedia.org/wiki/Plasma_cosmology

A theory of cosmology proposed by a Nobel Prize winning physicist (prize for magnetohydrodynamics, not cosmology)

In 2005, the wikipedia page for plasma cosmology looked like this:

http://bigbangneverhappened.org/wiki.htm

It's tough for me to ignore this, because it explains well so many things that other folks (particularly the ones I'm now ignoring here) don't even try to.

Both the quantum mechanics in the OP and what we have been talking about are addressed. I could probably have written some of this myself, but I didn't. I have no association with these people.

It's the first place on the internet I've found that has a reasonable explanation for the quantization of redshifts, and also discusses the related issue of quasar redshifts vs galactic redshifts, which I thought had either been explained long ago, or was simply ignored as if it was never observed. Unfortunately, the latter scenario (ignored, as if it was never observed) is what actually happened.

Mainstream cosmology also evidently missed any chance of explaining this:

http://www.dailygalaxy.com/my_weblo...-vast-quasar-groupings-found-in-astoundi.html

Which is the largest observed structure in the known universe. Another significant anisotropy that WMAP and Planck data utterly fail to address. A universe viewed only by means of microwave anisotropy is a view that is flawed by its own tunnel vision.

This is the end of my long litany and backlog of grievances against mainstream cosmology.

 

Dan, I can see nothing in any of this that calls into question the validity or utility of the concept of QM angular momentum and "spin", which is what the OP was all about. If there is, you will need to point out to me exactly where, so I can read it for myself.

If, as I suspect, there is not, this is another of your red herrings.

 

You should totally stop reading that stuff. It is definitely crap. Not only that, but the crazy people from the first link will deny that it has anything to do with the second link. Unless, of course, they are trying to make an argument from Nobel authority.

You are confusing a pleasant, easily digested explanation for a good explanation. You remain confused, as your posts indicate. You fail at the basics of relativity theory and you try to leap past them. If you would take the time to simply go over the basics, you probably have the skill to understand them and this would allay many of your concerns.

You should read the wikipedia page that you cited. On that page, it provides references to the actual scientific discussion of the supposed quantization. It was not ignored, it was analyzed and dismissed, many times. Sometimes, scientists get things wrong, even the ones that appear to hate the same things that you do.

Please stop basing your reasoning around hate.

 

I will see if I can reduce the scope of the argument a bit.

Of course, our understanding of quantum spin is good enough to make use of it for medical diagnostic imaging. That says a lot in favor of current models. It is the relationship between rotational or moments of inertia with equivalent linear inertia, and how one couples into the other that seems to be a theoretical dead zone.

 

But you do not need to worry about that in order to address the subject of this thread. All you need is that there appears to be intrinsic angular momentum associated with QM wave-particles, which in the case of charged particles is reflected in the magnetic moments we observe them to have. We call it "spin" because it behaves like it, mostly. Being angular momentum, i.e. the result of a periodic motion (i.e. rotation or "spin") it is quantised. Quantisation of any periodic motion arises (I simplify - rpenner may hate this!) because the path of the motion is equivalent to the wavefunction overlapping with itself as it retraces its path in a closed loop: one can only have constructive interference - i.e. a wavefunction that does not vanish - if the path is a whole number of wavelengths. (Same goes for orbital angular momentum of an electron in an atom, or for the rotation of whole molecules, as shown by the lines in their rotational spectrum.)

Some of the discussion relates to the projection of the momentum vector along an externally defined axis (Jz as distinct from J itself).

And then there is the Stat TD, which gets complicated due to different symmetry of combined wavefunctions for integer and half-integer spin particles. This results in the Pauli Exclusion Principle (which explains, inter alia, the periodic table), Fermi-Dirac vs. Bose-Einstein statistics (which explains superfluidity and superconductivity) and so on.

All this edifice relies on the idea of QM "spin", at least to the extent of those properties of spin which I have mentioned above. It is very fundamental. It is not just something used for medical imaging, as you dismissively imply.

 

If I sounded dismissive, it was not intended. I have the greatest respect for the periodic table, however, it is also clear since the discovery of the Higgs boson that inertia is something not entirely understood. In particular, bound energy becomes bound as matter by means of that quantum spin we are talking about. It involves interaction with a spin zero particle not even a part of atomic structure. The complete Lagrangian for atomic structure presently includes a term for interaction with the Higgs field that everyone ignored for the last 50 years. Spin doesn't happen in fundamental particles without Higgs. Neither does inertia.

Think of it as a new element we need to deal with, as heavy as a tellurium nucleus. It isn't technically a part of atomic structure, but that structure cannot exist without it.

 

If you knew what your limitations were you'd realize just how ignorant you are. Your limitation is you don't know what you're talking about but are convinced you do. The Dunning and Kruger thing about the lack of meta cognitive skills to properly analyze your limitations. The thing about the redshift is comical.

That's a good reason to never use wiki as a serious reference. Especially if you're a student involved in formal discussion. Genius can't be bothered with something as unsexy as SR.

 

Again, you are introducing ideas that belong to a separate branch of physical science. My earlier remark about the Somebody Else's Problem field was not entirely facetious. My point is that there is a massive amount of successful physics and chemistry that depends critically on the concept of quantum spin. If the true nature - whatever that might mean - of spin is open to discussion, that does not detract from its experimental success and thus its validity in our models.

Similarly, waffling on about the nature of inertia, mass and spin, as you are now doing, is all very interesting but irrelevant to most of science, as it changes nothing in the models I have been describing.

I have no problem with you trying to grapple with all that - indeed I wish I had the mental energy to do so myself - but I would entreat you NOT to keep introducing it, when OTHER aspects of science are under discussion. At the moment you seem to be Purveyor-in-Chief of Red Herrings to her Majesty the Queen, by royal appointment, or something.

P.S. Before anyone else points it out, I realise I got something a bit arse-about-face in my earlier description. The wavefunction symmetry issue is not part of Stat TD, it is what leads to both the Pauli Exclusion Principle and, from that, to the Stat TD considerations (fermions cannot occupy the same state, whereas bosons can, so the statistical probability of occupancy of states in an ensemble of fermions is different from that for bosons.)

 

Nicely stated. Well done, exchemist!

 

In case I didn't mention it, it is precisely those "spin states", both for fermions and bosons, which prevent them from flying off in a straight line at c into parts unknown, and which, once bound, prevent the fundamental particle or even the Higgs boson itself from ever achieving the speed of light in a straight line path in a vacuum. It is the field that enforces that straight line path at c for unbound energy in a vacuum as well. Spin is likewise a handy concept to have if you are determined that space must "curve" in every direction around a particle of bound energy (matter). I literally can't think of any other way something could cause that.

The graviton, according to the SM, is the only other boson that might, yet the SM doesn't specify where it is, how much energy it has, and specifies a positive value for spin, which is just bizarre. Forces always come in PAIRS in the SM. Photons and electrons. Quarks and Gluons. Gravitons and --? Energy exchanges happens in pairs as well. You can''t give energy to something that can't give it back; that would violate conservation of energy.

In physics, if not math, consistency is EVERYTHING.

 

This does not seem to make much sense to me. Can you please references for some of these assertions?

 

Obviously I can't give references for everything in the last post. But since no one in physics has apologized for predicting the graviton out of basically nothing other than what I have said, I don't feel the need to apologize either. If there is mathematical apparatus already in place to deal with gravity in that way, most likely it is wrong, and everyone knows it is impossible to prove that it isn't. I can't. I'm not even going to try. See the conundrum here? After a point, even the best science runs out of consistency. It will always be like that, whether some scientists are willing to admit that it is so or not.

 

In fact you apparently cannot give references for anything in your last post.