Re: Spin

carlip-nospam_at_physics.ucdavis.edu
Date: 10/04/04 

Date: Mon, 4 Oct 2004 19:29:06 +0000 (UTC)

Andr? Michaud <srp@microtec.net> wrote:
> Dan Bloomquist <EXTRApublic21@lakeweb.com> wrote in message
> news:<415E261D.5080804@lakeweb.com>...
 
[...]
> > And so far I've seemed to find atomic spin is not reconcilable with
> > classical angular momentum.
 
[...]
> The word "spin" was coined at the time, but is quite a misnomer.

> Electron spin relates to its magnetic aspect.

But spin *is* angular momentum, in the sense that only the sum of
spin plus orbital angular momentum is conserved, and in the sense
that spin can be converted to "ordinary" angular momentum. For
example, suspend an unmagnetized piece of metal from a thin thread
and magnetize it; as the spins align, the metal will start to rotate
(the Einstein-de Haas effect). Or place a magnetized *** of metal
on a turntable and raise the temperature until it demagnetizes; the
turntable will start to rotate.

Steve Carlip

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