Talk:Stern–Gerlach experiment
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[edit] external link
There is a nice explanation in this page: http://rugth30.phys.rug.nl/quantummechanics/stern.htm
but I do not have time to summarize/rewrite.
-- ato 21:35, 1 Sep 2004 (UTC)
[edit] Description Rewritten
Hey what do you think about the rewritten basic theory/description section? BeardedPhysicist 23:58, 14 May 2006 (UTC)
- pretty well written overall. nice. Mct mht 06:18, 17 June 2006 (UTC)
[edit] History?
Strange that there are no links to articles about Stern or Gerlach or even anything that says when this experiment was done! Michael Hardy 18:19, 9 Sep 2004 (UTC)
OK, now I've added some of that information. Various web pages say it was done in 1920, and others say 1922. Could it be that 1920 was the date of execution and 1922 was the date of publication? Just a guess. Michael Hardy 18:31, 9 Sep 2004 (UTC)
- I have added a section "Impact" where we can discuss all the related stuff that came AFTER that experiment. this will be usefull to include the links to more modern experiments or physics.
Alain Michaud 01:32, 23 December 2005 (UTC)
[edit] Original text was copied from external page
The original edit, as of 6 September 2004, seems to have been copied from [1]. I've left a note on the user's user page; I'm going to rewrite the article. -- Creidieki 02:44, 12 Sep 2004 (UTC)
[edit] Details
...is blank. Brianjd
[edit] Please excuse me while I dump these here for now
[edit] Question related to entaglement and this experiment
Imagine that you have this Stern-Gerlach apparatus but also another one on the rigt side (mirrored). Now if we send two entagled particles, one on the left and one on the right they will still be defleted up or down for some discrete value. Right? Now imagine that we changed spin of one particle (on the left side) while it was going through inhomogeneous magnetic field. That change will be transfered to the right particle instanteniously. That means that at the end particle will not be defleted at the some of previous 2 descrete values because we changed the spin while it was going through magnetic field. In that way if we want to transfer classical information from the left side to the right we can change states of the particles going through magnetic field on the left and on the right side we will se that particles are not deflected in some of 2 descrete values. In that way we can transfer classical information (change of the states of the left particles) to the right side faster than light. Can anyone explain what is wrong with this?
P.S. Feel free to change my question to meet standards of wikipedia. This is my first entry so I don't really now the rules. Thank you.
many details in the question posed are not necessary, e.g. one doesn't really need the G-S experiment and the question can be phrased in more general and simpler terms. following is the reply.
what's stated is wrong because the way you are proposing to send classical information is impossible. so one party, say A, locally manipulates the system, and through entanglement, causes state change in B. to send classical information means precisely that B performs a measurement, and, if this is going to work, must be able to recover the classical information according to measurement outcome. one can show that no matter how A interacts with the system locally, the measurement statistics on B's subsystem remains the same. this is exactly the statement of no communication theorem. similarly, quantum information can not be transmitted faster than light either. see also quantum teleportation. Mct mht 05:45, 17 June 2006 (UTC)
[edit] Spin numbers
For greater clarity I think the quantum number S and ms should be differentiated between. i.e. that electrons are fermions, and therefore posses a spin number of +1/2, which is a property intrinsic to the electron, and that the electron itself can be 'orientated' to give a projection spin quantity of +/- 1/2, which is a property of a situation or specific electron in an atom. In the experiment, all electrons, by their nature, have a spin number of 1/2, but have angular momentum projection number of +/- half when detected in a system, hence there being two possible (degenerate) quantum states for ground state silver- and the two lines.
Sorry if this doesn't make any sense! This article was recently slated by a university professor, but I feel it's content isn't wrong, just in-explicit.
Alexanderhowell 15:06, 6 March 2007 (UTC)
[edit] Purpose of the experiment
From the first paragraph of "Basic theory and description":
"The experiment sought to determine whether individual particles like electrons have any "spin" angular momentum."
Surely this statement is incorrect, as according to the Physics Today source [2] the experiment was originally conducted using silver atoms to test Bohr's theory of the atom (in particular "space quantisation", although I'm not sure what exactly this is supposed to refer to). Electron spin wasn't known about at the time and the experiment was only interpreted in terms of electron spin in 1927.
Pagw 14:46, 28 August 2007 (UTC)
- I think you are almost certainly right as to the purpose of the original experiment not being about electron spin. Rather than rewrite the sentence to talk about the original purpose, I'd suggest rewriting it to talk about the application to electron spin, which is the most talked about use for the apparatus. Teutanic 15:44, 31 October 2007 (UTC)
>(in particular "space quantisation", although I'm not sure what exactly this is supposed to refer to)
"Thus, depending on the orientation of the magnetic moment relative to the magnetic field there will be either an attractive or repulsive force and the beam will split into two components, exhibiting spatial quantization. ... If the beam is spatially quantized, as Sommerfeld predicted, two spots should be observed on the screen." http://plato.stanford.edu/entries/physics-experiment/app5.html
Is this helpful?
--Beroal (talk) 13:30, 29 December 2007 (UTC)
I was under the impression that this disputed sentence implied that they were investigating whether there was spin angular momentum in the sense of a rotating object -- not quantum spin which, as mentioned above, was not interpreted until several years later. It would be interesting to know whether any of this was true... I suppose tracking down the original paper describing the experiment might be a good idea. --Qrystal (talk) 16:35, 28 January 2008 (UTC)
