Testwiki:Articles for deletion/Quantum Hamiltonian

The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.

The result was delete. --Sam Blanning^(talk) 21:38, 27 October 2006 (UTC)

Quantum Hamiltonian

article consists of crankish claims. Mct mht 05:03, 17 October 2006 (UTC)

• Delete. Whatever the claims, it's a hodgepodge of things with the name "hamiltonian" in it.--CSTAR 05:23, 17 October 2006 (UTC)
• Delete - mishmash of BS. Michael K. Edwards 09:59, 17 October 2006 (UTC)

split. this article should only be about the classical relativistic hamiltonian as applied in QM. all other aspects not related to physics and regarding understanding the difference between classical mechanic hamiltonians and QM hamiltonians should be moved to a new page or abolished completely to avoid further confusion. however, a fundamental understanding of the difference of hamiltonians in QM application, classicals mechanics and other fields like group theory is needed and a brief overview of said differences be accessible from the Hamiltonian disambiguition page. andrej.westermann 12:04, 17 October 2006 (UTC)

Comment The nominated article is not the droid you're looking for. The quantum field theory analogue of the Hamiltonian is passably described in an interlocked set of articles including Hamiltonian (quantum mechanics). Michael K. Edwards 13:32, 17 October 2006 (UTC)

these are not covering what we are talking about. you just proved again the need for a clear identification that the Hamiltonian has at least two distinct but closely related meanings. you mention QM and this article is wrong placed there, agree. perhaps you would care to take your time to understand the issue other than just picking up on some flaming. 84.227.129.102 14:14, 17 October 2006 (UTC) oops, was not logged in. öandrej.westermann 15:57, 17 October 2006 (UTC)

• This AfD nomination was incomplete. It is listed now. DumbBOT 12:23, 17 October 2006 (UTC)

• Delete per above. -- Jitse Niesen (talk) 12:38, 17 October 2006 (UTC)

*Delete: this is either original research, or some useless, uninformative, malformed piece of weirdness. -- Ekjon Lok 13:53, 17 October 2006 (UTC) Cancel my vote. The article is certainly not perfect and needs a lot or work, but is no longer the utter nonsense that it was when I made my vote. Ekjon Lok 18:10, 17 October 2006 (UTC)

could we get a reply from another math whiz, please? preferably senior. i am getting tired to argue this and the argument shows the need. it is not original research. as some research might prove to the quick-dismissers. 84.227.129.102 14:10, 17 October 2006 (UTC) oops, was not logged in andrej.westermann 15:57, 17 October 2006 (UTC)

The article has been changed considerably since I made my vote, but I still maintain delete [delete vote cancelled, see above, Ekjon Lok]. The article currently cannot say anything other than what Hamiltonian (quantum mechanics) does for quantum mechanics, or Hamiltonian mechanics for classical mechanics. If you wish to add information on how to incorporate electromagnetism into Hamiltonian formalism, either in classical or in quantum mechanics, then add appropriate information to the two articles above. (I must also say, as an aside, that the article Hamiltonian (quantum mechanics) is itself not in the best of shape and definitely needs some work.)

the article tries to distinguish the two. they, or their applications should not be confused. again, a reason to keep it with a strong call for improvement, which has been this issue's history as far as i can trace it. andrej.westermann 17:31, 17 October 2006 (UTC)

Also, the current version of the article contains much nonsense. "Kamiltonian" is not a word.

it is. but again, not well known. look it up. or add the link. or follow it. there was a paper, for the time i have lost it, anyone care to help? how should i ever get to complete it if i constantly have to argue against completion due to being incomplete? andrej.westermann 17:27, 17 October 2006 (UTC)

The formula "H=T+E=E" is nonsense, did you mean "H=T+V=E"?

yep. corrected. thanks. andrej.westermann 17:27, 17 October 2006 (UTC)

The statement "Hamiltonian ... is time and mass independent" is pure, utter nonsense: how can Hamiltonian be mass independent for a massive particle?

AFAIK, it needs be mass independent initially to describe mass. andrej.westermann 17:27, 17 October 2006 (UTC)

The statement "Hamiltonian ... uses wave functions" does not mean anything; in first quantization Hamiltonian is an operator that acts on wave functions (states), it is the generator of time translations.

so why not phrase it better? will go and do. andrej.westermann 17:27, 17 October 2006 (UTC)

In short, the article now is in such poor shape that delete is the only option. After deleting, just redirect to Hamiltonian (quantum mechanics). -- Ekjon Lok 17:07, 17 October 2006 (UTC)

disagree as per comments andrej.westermann 17:27, 17 October 2006 (UTC)

Some replies:

• "Hamiltonian is mass-independent" is generally wrong. It does contain a parameter, $m$, the mass of the particle. Leaving aside subtle thins such as mass renormalization (which only occurs in QFT), this is the mass of the particle. The typical example would be $H=p^2/2m$. Your example contains an $m$ under the square root sign.

• yep. tried to clarify. same content, different context. anyone please help me put this clearly? that's what this is about. no less, no more. thanks andrej.westermann 17:47, 17 October 2006 (UTC)

• Most importantly, read my comments at the end of this section: if this article is really cleaned up and improved, it cannot be anything other than the standard discussion in Hamiltonian (quantum mechanics). It will only duplicate existent material. Currently it does not say anything new, anything that other articles on Quantum Mechanics on Wikipiedia do not say. Quite frankly currently it does not say almost anything at all.

-- Ekjon Lok 17:38, 17 October 2006 (UTC)

• Cleaned up. andrej.westermann 15:00, 17 October 2006 (UTC)

suggesting removal of AfD as further investigation indicates attack from a possibly biased group of contributors. Before you take offense, note that i said possibly, as it is my interpretation from reading Mathematical formulation of quantum mechanics and the corresponding Talk page. Wikipedia is NOT a peer review system for ideas, so different views should not try to delete each other. It is maybe a presentation peer review system of some sort and any comments should be taken serious, even if they come from seemingly opposed positions. As you can see, i am trying to oblige. But again, opposition to the views held in an article does not directly lead to AfD, as said authors might appreciate themselves.84.227.129.102 15:44, 17 October 2006 (UTC) oops again andrej.westermann 15:57, 17 October 2006 (UTC)

For me, this argument is over, the contested article has been cleaned and contributions to the Hamiltonian Operator are in preparation. As far as i can see, all sides should be satisfied so far. Comments? 84.227.129.102 15:44, 17 October 2006 (UTC) and oops again. i am not my sockypuppet :) andrej.westermann 15:57, 17 October 2006 (UTC)

Still Delete, as it has gone from being weirdness to empty, redundant, and poorly sourced. I'm sorry to be a wet blanket, Andrej, but I don't see a need for this article. Michael K. Edwards 16:01, 17 October 2006 (UTC)

we know already. you might want to read the AfD guidelines again. Better yet, show an understanding of the argument instead of making crude claims to irrelevance. This article has been suggested long time ago, see Talk:Hamiltonian mechanics. Maybe i have missed its existence, which would be the only claim for deletion (or merge) i could accept. andrej.westermann 16:14, 17 October 2006 (UTC)

the references are fine, but there seems to be a link repeatedly breaking to Eric Weisstein on Wolfram Science World. should be better now. andrej.westermann 17:09, 17 October 2006 (UTC)

again, this whole discussion seems to be vs people not being aware of this Hamiltonians significance, which to me is just te argument to keep it. If you would help phrase why it can be disregarded in your fields, that would really improve the article. i have tried in the intro but naturally can not make a convincing case to irrelevance :). The subject itself will always stay short and precise but because of its implications (and differing interpretations as to validity), it should stay separate. andrej.westermann 17:09, 17 October 2006 (UTC)

• I simply do not understand why you want to create a separate article. Hamiltonians are indeed very important. They are important in classical physics, where they are certain functions of coordinates and conjugate momenta (and possible explicit time), and they can be used to obtain equations of motion as Hamilton's equations. They also have a geometric significance, as generators of time translations, using symplectic manifolds, Poisson brackets etc. All this is described in the article Hamiltonian mechanics. They are also very important in quantum physics, where they are operators that act on states and again are generators of time translations. They can then be identified with energy operators, for example in the famous time-independent Schrödinger equation$H|\psi ⟩=E|\psi ⟩$, where $H$ is the Hamiltonian (operator), $|\psi ⟩$ is the eigenstate of this operator and $E$ is the energy, the eigenvalue. All this is described in the article Hamiltonian (quantum mechanics). I do not see what can you possibly say in a new article that is called "Quantum Hamiltonian" that is not already said in one of these two. -- Ekjon Lok 17:22, 17 October 2006 (UTC)

• exactly the point. there is no need to state anything new but there is a need to state the differences you just mentioned in one article. they do well make the distinction themselves, however, for the layman, this distinction gets easily confused and i am still looking for a way to clear this. so far, this is the way and i have tried keeping links to it few and if possible only from the disambiguition page or the areas you mentioned.andrej.westermann 17:37, 17 October 2006 (UTC)

• I suggest reading good books on Quantum Mechanics. You can always use Wikipedia as a secondary reference, to clarify concepts that seem unfamiliar. Generally, the connection between classical Hamiltonian and quantum Hamiltonian is made via the "canonical quantization" formalism: the Poisson bracket is replaced by commutator (times some factors such as $i$ and $\hslash$). Classically, Hamiltonian is just a function (in most cases it is just the energy). In quantum mechanics Hamiltonian is an operator. In both cases they can be viewed as time translation generators (classically by the Poisson bracket action, quantum-mechanically by direct action on state vectors, or by commutation on other operators). All good books on quantum mechanics usually describe this. -- Ekjon Lok 17:48, 17 October 2006 (UTC)
• Final final comment: if you really want to write an article on how Hamiltonians are used in classical and quantum mechanics, what are the connections, what are the differences and similarities, then it should not be called "Quantum Hamiltonian". It should be called something like "Hamiltonian in classical and quantum physics" or something similar. That might, indeed, be quite useful. -- Ekjon Lok 17:56, 17 October 2006 (UTC)

• yep. now i'm starting to understand. i support this point totally, see discussion :) thank you very much! andrej.westermann 18:01, 17 October 2006 (UTC)

conclusion: suggest move as per EkjonLok to new page Hamiltonian in classical and quantum physics or equivalent and then delete this. help still appreciated. andrej.westermann 18:01, 17 October 2006 (UTC)

does anyone read the original argument? Talk:Hamiltonian_mechanics andrej.westermann 17:38, 17 October 2006 (UTC)

• Comment: What was this Hamiltonian called by theorists who worked on it? Obviously it wasn't called the quantum Hamiltonian before QM existed. Gazpacho 17:58, 17 October 2006 (UTC)

• Delete (as mostly nonsense, and the remainder being an essay; signed, etc.) and possibly create a new page Hamiltonian in classical and quantum physics. (For what it's worth, the "source" for Kamiltonian is worthless as reference.) — Arthur Rubin | (talk) 19:11, 17 October 2006 (UTC)

yep, this reference to kamiltonian is nada, have seen other though, anyone remembers? been busy otherwhise... :) andrej.westermann 19:32, 17 October 2006 (UTC)

• still move and delete waiting 24h for other suggestions/objections. there is enough material out there. i apologize from the confusion. any help much appreciated. so far, all comments very appreciated, thank you all! andrej.westermann 19:32, 17 October 2006 (UTC)

Quote from above: *Final final comment: if you really want to write an article on how Hamiltonians are used in classical and quantum mechanics, what are the connections, what are the differences and similarities, then it should not be called "Quantum Hamiltonian". It should be called something like "Hamiltonian in classical and quantum physics" or something similar. That might, indeed, be quite useful. -- Ekjon Lok 17:56, 17 October 2006 (UTC)

For what it's worth, I consider the relationship between Lagrangian and Hamiltonian formulations of a physical theory to be about the deepest topic there is in mathematical physics. If you can treat it with any remotely useful degree of mathematical accuracy within the constraints of a Wikipedia article, you're a better man than I am. I think I'll just skip the rant and point out that http://www.claymath.org/millennium/Yang-Mills_Theory/ is an offer of a million smackeroos more or less for an explanation of how a sane Hamiltonian can emerge from a realistic Lagrangian. In the meantime,

• Hamiltonian mechanics is decently accurate but opaque to all but the most sophisticated readers, and should perhaps be moved to Hamiltonian (classical physics);
• Hamiltonian (quantum mechanics) is a jumble but at least links to most of the relevant terms;
• Hamiltonian (quantum field theory) is missing; it should bring probably together concepts like Dyson series, interaction picture, and canonical quantization, and explain why the BRST formalism seems largely to have eclipsed the latter; and
• Quantum Hamiltonian delenda est.

Michael K. Edwards 22:27, 17 October 2006 (UTC)

• Delete, don't move; this has no content and is still mostly wrong. Please feel free to plan new articles from scratch. Melchoir 22:14, 17 October 2006 (UTC)

• To clarify my short delete comment above: Of course the connection between classical and quantum mechanical Hamiltonians is a valid subject. My delete should not be interpreted as opposing that somebody write about this, either in Hamiltonian (quantum mechanics) or in a new article. However, the first step is necessarily to delete the current text. -- Jitse Niesen (talk) 02:47, 18 October 2006 (UTC)

• Strong delete with possible further action. I've tried to use cascade-formatting to make this legible; there is a lot to note here.

This is illustrative of the problems with many specialized-field science articles on the encyclopedia at this time. At its best versions, it has duplicated the effort of the two existing articles discussed in above notes. At its worst, it has been disingenuous and factually inaccurate. The justifications given on the article's discussion page are particularly circuitous or nonresponsive. And, of course, the references are varyingly unacceptable (a toequest.com forum post), extraordinarily generic links that are functionally definitions, or wholly inapplicable to the topic discussed (William H. Rowan's original work). The encyclopedia has standards for math and science articles that are steeper than those for, say, popular culture, and this does not meet them.

Wikiproject Physics has largely concluded this author is, to use their words, "a crank or a prankster". This article and references to it have been systemically poor since inception, and have been all but exclusively the playground of a single-topic account (andrej.westermann) and a veritable host of sockish-seeming IPs (84.226.146.13, 84.227.60.147, 84.227.80.45, 84.227.129.102, 89.217.60.227), perhaps from a semi-dynamic host. As further evidence of the curious lack of transparency by this editor, the piped link to this page from Swinging Atwood's Machine is particularly evasive -- AfD readers will likely have to examine the article code to even locate it. This diff from Quantum mechanics illustrates the use of another inappropriately piped link to this article by this IP cluster.

OOOh, this link looks like a nasty hack. apologies. the article started from a hodograph... ouch, am ashamed. andrej.westermann 20:30, 18 October 2006 (UTC)

Even if a seperate article under this name were viable (which I do not believe to be true), this must not be the way to go about it. Serpent's Choice 06:47, 18 October 2006 (UTC)

• Followup note: all of the above-listed IP addresses are from DSL provider Sunrise in Switzerland. The likelyhood that they are the same editor is very strong. Serpent's Choice 06:58, 18 October 2006 (UTC)
• Delete this as an unusable version. Followed by cleanup and harmonization of all Hamiltonian-articles we have (about 20, see Wikipedia_talk:WikiProject_Physics#Hamiltonian_articles). --Pjacobi 08:48, 18 October 2006 (UTC)

DELETE absolutely and agree to all except the sockypuppet theory and making obscure critical comments (including yours truly), will be logged in always when doing even minimal maintenance and generally get informed about most anything re Wiki and applied Hamiltonian. Final comment: E=mc² as polar spherical hamiltonian brought me here, please excuse my other ignorance and any trouble caused therefrom. THANKS A LOT! andrej.westermann 20:25, 18 October 2006 (UTC)

• Strong Delete. There are a variety of existing articles that cover this set of topics in great detail. There's nothing here to save or move or split. linas 03:59, 27 October 2006 (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 a deletion review). No further edits should be made to this page.