- #1

nouveau_riche

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what does it mean by a spin 0 particle?

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- Thread starter nouveau_riche
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- #1

nouveau_riche

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what does it mean by a spin 0 particle?

- #2

Simon Bridge

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That is usually covered in textbooks and basic references on the subject - eg. you can google for it and get millions of them. Perhaps there is something about the usual explanations that puzzles you?

eg.

http://www.scientificamerican.com/article.cfm?id=what-exactly-is-the-spin

- #3

shahbaznihal

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As far as the question of measurement and subsequent quantization of Spin is concerned I will agree with Simon that you can find tons of information on this in any undergraduate book on Quantum Mechanics.

Good luck!

- #4

mpv_plate

- 87

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what does it mean by a spin 0 particle?

If the wave function of a particle is unchanged when rotated by 2π/s radians, the particle has spin s. For example photon has spin 1, thus its wave function is unchanged when rotated by 2π (360 degrees, or one full revolution around an axis). Electron has spin 1/2, so you need to rotate its wave function twice around the axis (720 degrees) to get the same wave function. If a particle has spin 2, it is sufficient to rotate it by 180 degrees to get the same wave function.

Fields with spin 0 are scalar, fields with spin 1 are vector fields, fields with spin 2 are tensor fields.

- #5

nouveau_riche

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If the wave function of a particle is unchanged when rotated by 2π/s radians, the particle has spin s. For example photon has spin 1, thus its wave function is unchanged when rotated by 2π (360 degrees, or one full revolution around an axis). Electron has spin 1/2, so you need to rotate its wave function twice around the axis (720 degrees) to get the same wave function. If a particle has spin 2, it is sufficient to rotate it by 180 degrees to get the same wave function.

Fields with spin 0 are scalar, fields with spin 1 are vector fields, fields with spin 2 are tensor fields.

i am not getting the reason to bring the concept of spin

- #6

nouveau_riche

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eg.

http://www.scientificamerican.com/article.cfm?id=what-exactly-is-the-spin

i am not getting the reason to include the concept of spin

- #7

DrChinese

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i am not getting the reason to include the concept of spin

Well, without this additional degree of freedom, it would not be possible of accurately describe many things. How about the number of electrons in different atomic shells? Or behavior of particles with known spin?

The point being that spin needs to be included to properly explain various particle behavior.

- #8

Kholdstare

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- #9

jtbell

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- #10

nouveau_riche

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what is that "something" you are talking about?

- #11

Kholdstare

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what is that "something" you are talking about?

I told you already. Electrons obey quantum mechanics and the quantum mechanical description of spin can not be understood by drawing

- #12

jtbell

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what is that "something" you are talking about?

He already gave you the best current answer to this question:

(we don't know what that electrons do, when they "spin").

All we can do is calculate the effects of "spin" on things that we can actually measure.

- #13

Simon Bridge

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i am not getting the reason to include the concept of spin

It is a name for a property... like strangeness or charm for quarks. In this case chosen for the similarity in the math and its relationship to things like moment of inertia and magnetic moment. A name does not

- #14

nouveau_riche

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could you please show me what you said, with an example

- #15

jtbell

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I first read about the Einstein-deHaas effect nearly forty years ago, in the Feynman Lectures on Physics (which were themselves written about ten years earlier).

- #16

DrewD

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If you bounce a spinning ball it will deflect from the floor (or whatever it hits) and move off in a different direction. There is no exact analogy, but electrons will have their paths changed in a way that makes sense if one assumes they have the same mathematical trait that a spinning ball has (angular momentum). But they are not balls and they are not spinning, so it is just a trait that they intrinsically have.

This may not be satisfying, but none of us can do anything about that.

- #17

Drakkith

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could you please show me what you said, with an example

There is no way to give you a picture of quantum spin that would be accurate. It simply has no analog with classical physics. Instead I suggest thinking of it as a fundamental property of a particle, like mass and charge are. Personally I view angular momentum and spinning at the macroscopic level as an imitation of the quantum property, like how mass adds up with each particle that makes up an object.

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