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Page title[edit]

Should'nt this be named spin operator? Karol 19:40, 28 October 2005 (UTC)


Recent edits seem to suggest that all fermions have spin of 1/2. However, I was under the impression that fermions have half-integer spin (not necessarily 1/2).--GregRM 02:51, 16 March 2006 (UTC)

You are right. What I really meant is that all fundamental particles that are fermions have spin 1/2. Of course, composite particles can have any integer or half integer spin. I have changed the article accordingly. Thanks for the catch. Grokmoo 03:51, 16 March 2006 (UTC)
It is still slightly unclear. The definition says

Fermions have half-integer spin.
Spin-½ particles constitute an important subset of such fermions.

Assuming that an important subset is strictly a subset, one derives that while having half-integer spin implies being a spin-½ particle, the opposite is not necessarily true. That, in turn, reveals the difference between half-integer and ½, after possibly excluding that the dash should be interpreted as a minus. Would it be overwhelmingly pedantic to state that Spin-½ is the property of particles whose spin is ½? Hmm... I'll do it. ale (talk) 13:41, 3 May 2009 (UTC)

Unclear use of dash[edit]

After reading this article, some people may be confused by the expression 'spin-1/2' - in that does it mean a spin of negative half, or positive half (with a dash just for linkage)? This should probably be redefined or at least explained in the article. Harabanar (talk) 11:21, 15 September 2009 (UTC)

Heisenberg picture[edit]

How does the spin operator look in the Heisenberg picture?


How should Spin-½ be pronounced..? "half-spin", "spin minus a ½"..? For outsiders it is not obvious. --Harabanar (talk) 11:21, 15 September 2009 (UTC)—Preceding unsigned comment added by Harabanar (talkcontribs) 08:06, 15 September 2009 (UTC)

In the CRC Handbook, the spin of 4Be8 is given as zero. Then the spin of 4Be9 is given as -3/2. And the spin of 5B10 is given as +3. What is that supposed to tell me? WFPM (talk) 03:06, 14 November 2008 (UTC)

That nuclei are composite particles. Eutactic (talk) 02:47, 12 October 2010 (UTC)

Wave function[edit]

Can we put the wave function of the electron in the article? Jackzhp (talk) 16:36, 23 October 2013 (UTC)

Spin as consequence of ...[edit]

This claim seems not true, spin 1/2 seems to be explained by Heisenberg by the 1st time. Jackzhp (talk) 20:17, 23 October 2013 (UTC)

Mathematical Description Section[edit]

This sections sounds as if it was written by a non-native English speaker, so I'll try to clean it up. It could also use some fleshing out as it's rather sparse at the moment but covers a topic that's critical for undergraduate studies in physics. — Preceding unsigned comment added by ArchetypeRyan (talkcontribs) 04:36, 7 November 2013 (UTC)

Also, I would be very careful of citing McMahon's book QFTD. His publisher McGraw-Hill Education is notorious for farming out much of the production work on its books to Conveo, and the proof-reading tends to be abysmal, with dozens of errors. We removed McMahon's book Quantum Mechanics Demystified from the References in the article Angular momentum operator for just this reason: hundreds of typos.Edgeorge (talk) 00:01, 1 February 2014 (UTC) Duncan