Wikipedia:Articles for deletion/Spherical decay experiment

This page is an archive of the proposed deletion of the article below. Further comments should be made on the appropriate discussion page (such as the article's talk page or on a Votes for Undeletion nomination). No further edits should be made to this page.

The result of the debate was keep and cleanup. – ABCD 18:31, 11 July 2005 (UTC)

[edit] Spherical decay experiment

There is a problem with the ability of inexperienced persons interested in science introducing ostensible paradox after paradox (the oldest probably being the twin paradox in relativity). The result is that these fanciful "puzzles" sit and await criticism by better-versed physicists, as well as spreading like the so-called urban legends. This "puzzle" has no merit, as there is no way to say when the atom decays, so there is no way to say when the inner hemisphere has been passed up. Pdn 5 July 2005 05:14 (UTC)

• Comment Wouldn't it be better to edit the article to demonstrate/explain how the paradox is resolved/not a paradox? GBM 5 July 2005 11:57 (UTC)
• Weak keep Is this notable or not? If it is a well-known thought experiment, then it should be kept with notes in the body of the article. If this was made up for Wikipedia, then it should be deleted. Google was inconclusive on this point, and may not be a good source for notable QM theory. Someone with credentials or at least a decent source citation want to comment? -Harmil 5 July 2005 13:15 (UTC)
• Strong Keep. This is a famous paradox first formulated by the mainstream physics community in the 1920's and 1930's and is a standard part of undergraduate quantum mechanics education. The entire business of experimental high-energy physics is built upon this effect. This is a nuisance delete aka VfD vandalism. linas 5 July 2005 15:41 (UTC)

FWIW, I'll take the next 24/48 hours to expand the article to bring it closer to a standard presentation. I'll try to find references; I'm not sure, but I think its Max Born who came up with this. linas 5 July 2005 17:18 (UTC)

• The text appears reasonable. It would be useful if it actually cited a source for the gedanken experiment. But I don't see anything inherently irregular about it. It helps capture some of the inherent wierdness of quantum mechanics. Keep — RJH 5 July 2005 16:27 (UTC)
• Comment A Google search for Spherical decay experiment returns 168,000; however, a Google search for the same with quotes returns two, both from Wikipedia. Perhaps there's a better name for the article? Does the experiment actually have an actual name? BorgHunter July 5, 2005 21:39 (UTC)
• Weak Keep: This is a known thought experiment, but the article is unclear. It should avoid wavefunction collapse since that is a philosophical construct, not an observable. (The state of a system between measurements is not part of quantum mechanics or any other science.) Peter Grey 6 July 2005 00:30 (UTC)
• Keep and Cleanup Problems with article quality are not grounds for deletion of a valid topic. Xoloz 6 July 2005 03:55 (UTC)
• Keep and cleanup. Encyclopedic topic. JamesBurns 6 July 2005 07:01 (UTC)
• Is this original research? There is no mention of a paradox of this name in any of the quantum mechanics books in our library, nor do any of my colleagues seem to recognize this name. Furthermore, as currently written, the nature of the paradox is obscure, as pointed out by the nominator. Before calling for a delete I would ask the editor to cleanup at least in the following ways:
  • Give references to prove that the effect has been described and named before.
  • Early in the article state exactly what the paradox is.

Maybe the editor would actualy like to add an example to the article on wavefunction collapse instead? Bambaiah July 8, 2005 15:28 (UTC)

Bambaiah, a better name can be found for this article, I am not yet sure of what that better name would be. The first part, about the collapse of a spherical wave function to a single trace in a cloud chamber, is due, I believe to either Wilson, the inventor of the cloud chamber, or one of his contemporaries, maybe Bohr, presumably in the 1920's. The "paradox" is obvious: how does the spherical wave function of a decaying nucleus turn into a straight ray in a cloud chamber? I will try to change the article to state this in an even more straightforward manner. I'm trying to find a reference; as that will then provide the correct name under which this is more commonly known under. You and I have had arguments in the past, and I'm sorry if I insulted your intelligence, but lashing back out with language such as "Is this original research?" is inappropriate and out-of-line. linas 06:32, 10 July 2005 (UTC)

Ah, the magic of google. A breif search shows that it is known as the Mott problem, formulated by Mott in 1929. I added refs to the article. The only things I found on-line that mention it are to far off-topic to cite:

• Andrew Platt, Ken Kiers, Wytse van Dijk, Numerical Simulations of Alpha Tracks (appears to be a student project guided by a professor)

• Mario Castagnino1 and Roberto Laura, Functional Approach to Quantum Decoherence and the Classical Final Limit: The Mott and Cosmological Problems, International Journal of Theoretical Physics, 39 no 7 pp 1737-1765. [1]

• J.J. Halliwell, Trajectories for the Wave Function of the Universe from a Simple Detector Model, (2001) Phys Rev D 64 pp 044008.

Appearently, astrophysicists enjoy looking at this problem. -- linas 16:40, 10 July 2005 (UTC)

Since the language bothered you, I struck it out, and I hereby take it back. The revisions are nice. Maybe one could think of a name change? I mean this purely as a practical matter: since the effect that is being talked about is not usually known by the name that it has been given, people are unlikely to look for it in a pedia by this phrase. An appropriate name change would make it more useful. And my vote is now a keep. (Or should that be a move or redirect?) Bambaiah 09:12, July 11, 2005 (UTC)

Seems clear to me now that the right thing is to split the article into two: the Mott problem and the Renninger negative-result experiment. Curiously, we have no articles on the better-known Mott scattering and Renninger effect. Oh well. linas 14:40, 11 July 2005 (UTC)

• Keep. A while now since I went to QM lectures. On a read through and look at the references it says the right kind of things and is interesting. Its most ardent supporter was also the guy who wrote it, and as yet I could not be certain it is not a spoof as suggested by others. But it is important that this subject be addressed by wiki. It is correctly stating that this is an important class of issue for people to think about, even if they do not know it. Don't know what other related articles exist. If there are some then it might be merged, otherwise it is a must keep.Sandpiper 02:52, 10 July 2005 (UTC)

Maybe it has been revised, but doesn't it say the half life of the particle being studied is short enough that it must have decayed during the time of the experiment. It is sufficient to know it has almost certainly decayed without knowing exactly when.user:sandpiper

The most ardent supporter has a PhD in theoretical particle physics and feels that he knows what he's talking about, and has spent some time trying to fight off crank physics edits on wikipedia. This article was created in order to document one of the half-dozen classic pozers on quantum measurement. linas 06:32, 10 July 2005 (UTC)

Well who knows, perhaps we went to the same lectures, the number of physics graduates is going down. I was happy enough to remember who EPR were before it said.Sandpiper 17:08, 10 July 2005 (UTC)

Found an online reference for the second half of the article; its a reprint of an older journal article: here, see section 4.1 I am still missing names and references for the first half. linas 07:30, 10 July 2005 (UTC)

Appearently, the thing described in the first half is known as the Mott problem; see cites above. I've added a full set of Cites to the article (but not the cites above, which are off-topic).linas 16:43, 10 July 2005 (UTC)

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in an undeletion request). No further edits should be made to this page.