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Can the spin of an electron be understood as originating from an open string rotating around a perpendicular axis through its midpoint?

Qmechanic
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John Eastmond
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    Why would you think so? – ACuriousMind Jan 05 '22 at 16:20
  • How else would you picture particle spin? – John Eastmond Jan 05 '22 at 16:23
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    I don't "picture" it at all, and I do not understand how the specific picture you present is supposed to relate to spin. – ACuriousMind Jan 05 '22 at 16:32
  • A question about an unintuitive concept. Why the downvotes? – Philip Wood Jan 05 '22 at 16:35
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    @PhilipWood I didn't downvote because the question is "about an unintuitive concept", I downvoted it for asking about the correctness of a very specific picture without any motivation at all for why one would arrive at this picture or why it should be correct. – ACuriousMind Jan 05 '22 at 16:44
  • @ACuriousMind Point taken, but I don't think it's unreasonable for a learner to propose as a model a simple system which does have angular momentum, and to invite comments. Thanks for explaining your downvote. – Philip Wood Jan 05 '22 at 17:54

3 Answers3

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I copy from my answer here,

When measurements started to look at the microcosm of atoms and particles, the conservation rules of energy, momentum were found to hold in the interactions, BUT unless an intrinsic angular momentum was given to particles, conservation of angular momentum would not hold. So by experimental observations a fixed angular momentum, called spin, was assigned to all elementary particles so that the observations would fit the quantum theory that was developing. This has been validated over and over again with all measurements.

If you are talking about strings as in string theory , where the electron is an excitation of a string, the same holds, because the excitation is chosen so that it fits the data known for the electron, it is an "assigned" mathematical location to fit the existing symmetry groups of the standard model. They are quantum excitations , not classical states rotating .

anna v
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The spin of elementary particles can be understood as a rotation in the mathematical sense, due to it formally behaving like the ordinary angular momentum of three dimensional space. In that regard, you can assimilate it with the image of a top (for example) spinning about its axis, provided that you quantize the motion. But that's about as far as analogy goes. In your example of an electron, the property itself has nothing to do with a physical body rotating about an axis attached to it. But curiously enough, in a way it behaves as if that were true.

The original experiment of Stern-Gerlach revealed the quantization of angular momentum, while the angular momentum picture of spin was first proposed by Goudsmit and Uhlenbeck a few years later.

deneb.algedi
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Fundamental particles are point like so they cannot be spinning.The quantum spin of a quantum particle is just something which gives the quantum particle angular momentum.

Jun Seo-He
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  • But as I understand it string theory speculates that fundamental particles are actually $1$-d objects. I’m trying to picture how such an object can have angular momentum. – John Eastmond Jan 05 '22 at 18:48
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    Either way t doesn't spin like classical particles. There isnt a axis of rotation.Stop thinking classically when you are studying quantum particles. – Jun Seo-He Jan 05 '22 at 19:23