[BilboGrabbins (OP)]

Only a half week ago, I said here that we may need to have a revision for particles as being slightly extended ie. Like a corpuscular sphere, and someone replied, "Why do that for an inferior theory?"

I explained it wasn't inferior,  classical spin and quantumspin differ only slighly but the implications are massive for divergence theory issues. A news article came up on  my feed and a new condensus agrees with this. Spin is more and more looking like classical theory.


https://physicsworld.com/a/evolution-of-quantum-spins-looks-surprisingly-classical/?fbclid=IwAR2IxwmEQA6Vnyp5BX2HaUUFy-KC-N87yAY3qUN4rxgB_sGw2f0oAVEyXTY

[Origin]

Spin is more and more looking like classical theory.

That is your 'spin' on the article, but not mine.  I read the article to say that you can model the bulk behavior of particles using a more classical approach, akin to Ficks law.  The article does not say that the spin of a particle is more like classical spin than quantum spin.

[yor_on]

I will agree with Origin in that.  It's not classical at all. A simple proof is that the spin would have to be faster than lights speed in a vacuum to be anywhere 'classical', and that one is from the beginning of quantum mechanics. Think it was Heisenberg that commented on that one. And as far as I know we don't have anything 'faster' than 'c' here. Entanglements and superpositions ignored.

https://www.askamathematician.com/2011/10/q-what-is-spin-in-particle-physics-why-is-it-different-from-just-ordinary-rotation/
=

Thinking of it, there is this added meaninglessness in trying to describe it classically when you consider that HUP doesn't define a particle, before a outcome. You can 'photograph' a electron, but when doing it you finalize all parameters in that action. Before that action it was a 'cloud' consisting of a probability of localization, after that photo it should no longer be probabilistic. ( that is also part of quantum computing, how to keep a system untouched. )

Although that assumption, that it no longer is probabilistic becomes in general terms. The cloud will still be there even after you photographed it. You can repeat it over and over again with a defined 'localization' of all parameters each time.

[yor_on]

But it connects to both, superpositions and entanglements. As when trying to create a Quantum computer.

https://www.ibm.com/ibm/history/ibm100/us/en/icons/spintronics/

and  'learn quantum computing' by IBM    https://quantum-computing.ibm.com/composer/docs/iqx/guide/
=

Let's add this one   https://towardsdatascience.com/demystifying-quantum-gates-one-qubit-at-a-time-54404ed80640

[Bored chemist]

Spin is more and more looking like classical theory.

That's an interesting way to interpret a paper which says
"Evolution of quantum spins looks surprisingly classical"

The article makes it clear that the spin is quantum (it would have to , because that's what the evidence says).

It says the way in which it changes resembles a classical process, but that's a different topic.