Talk:Quantum mechanics/Archive 7

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Archive This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.


Contents

Link purge

I zapped several crufty and/or downright crackpotterly links from the "External links" section. Misinformation does not need the implied endorsement and the added publicity that our "encyclopedia" provides. For a dress-down of the Hindu "Vedanta" flavor of pseudophysics, see Alan Sokal's article "Pseudoscience and Postmodernism: Antagonists or Fellow-Travelers?" (2006). Anville 19:19, 2 June 2006 (UTC)


Relational Quantum Mechanics and Modal Interpretations of Quantum Theory

We need some people who are comfortable with this topic to describe these interpretations of QM. RK 19:15, 17 June 2006 (UTC)

Rename and Reform?

Isn't "Quantum Physics" or "Quantum Theory" a more appropriate title, with "Quantum mechanics" linked to this article? The application of quantum theory to, say, electromagnetic fields surely isn't in the domain of "mechanics," at least not as understood by the college student who is introduced to mechanics and electromagnetism as separate subjects. Quantum theory has much broader scope than mechanics; surely the Wikipedia naming conventions aren't so deferential to commonly familiar terms that we should apply such a misnomer to this article. (?!?)

In general, with respect to those who have undertaken the difficult task of contributing, this article is a sprawling, incoherent mess. Perhaps it would be appropriate to give a concise introduction to the theory with clear links to articles at several levels of sophistication. Technically sophisticated readers will benefit little from wordy paragraphs or sentences which begin with "An equation known as the Schroedinger Equation...," while novices can hardly be expected to follow the equations and mathematically rigorous language which is sorely needed in this article. As it stands, this is hardly a "technical" article, as implied by the statement at the top.

Is there any hope that a group of concerned physics professors from major universities will take responsibility for maintaining this important page???

Gnixon 23:59, 23 July 2006 (UTC)

Please append your edits to the end of the page --Ancheta Wis 01:20, 24 July 2006 (UTC) moved

Quantum causality

I was under the impression that causality (cause begets effect) does not apply as definitely in the quatum realm as it does in the classical, that effects can chronologically preceed their supposed causes. After watching The Elegant Universe and doing some brief reading on the subject, this was one of the things that I gathered. It is, to me, interesting enough to include on the QM page, if accurate. Though, since I have no formal experience with QM I did not want to add it to the article without backing. --HantaVirus 14:47, 27 July 2006 (UTC)

Entanglement objection

Under the discussion of entanglement under "Quantum mechanical effects" the issue of the violation of special relativity is not handled with much care. "If quantum mechanics is correct, entangled particles can display remarkable and counter-intuitive properties. For example, a measurement made on one particle can produce, through the collapse of the total wavefunction, an instantaneous effect on other particles with which it is entangled, even if they are far apart. (This does not conflict with special relativity because information cannot be transmitted in this way.)" August 2nd 2006 11:13 PST. This last statment is simply false and was the major issue posed to Bohr by Einstein. The thought experiment goes something like this: Imagine two particles with known opposite spin (because of a paramagnetic effect or whatever). Both particles have underknown spin until one is measured, then the other is instantaniously known, before information (which can't travel faster than the speed of light, no matter what the article claims) can travel to the other particle, thus violating SR. A few experiments have been preformed, but nothing conclusive has come from any of them, and this remains a major question in QM from my understanding. I would hope this could be corrected by someone with a little more technical background than myself.

No, I'm pretty sure you cannot transmit information via QM entanglement. Unless you are the particle in question and the information you are transmitting is your unknown state. What I mean is that an experimenter cannot use entanglement to transmit arbitrary information faster than light. Even if, at some level, in order to make things work out, it seems that some "information" must be moving faster than light, it is not information that we can ever use. It is certainly not information that would allow someone to violate special relativity (send information beyond a light cone, predict the future, etc.) and it is not transmitted by a wave or particle as far as we know, so it doesn't violate relativity. A faster-than-light quantum entanglement "radio" can never exist. And I've never heard that that is somehow a controversial issue or that any physicists disagree that QM cannot transmit information faster than light. I'm not a physicist, but I've asked a couple of them about it and this is what I was told. Xezlec 16:43, 5 August 2006 (UTC)

No information can be transmitted by Bell states without classical communication. Though the quantum state is changed by the measurement of the first particle(collapse of wavefunction), there is no observable change in the state unless the measurement outcome is first communicated to the second particle.Waxigloo 17:43, 26 August 2006 (UTC)

Entangled cat

To avoid repeating the same text again, I am putting a link to my comment about Schrödinger's cat: [[1]]. David R. Ingham 20:50, 23 August 2006 (UTC)

See also Introduction to quantum mechanics#Quantum entanglement which is only about locality. Bohr's answer to Einstein, that 'what is described is a system', means that no new info is transmitted (it's the same system). --Ancheta Wis 21:42, 23 August 2006 (UTC)

Merge with quantum field theory ? Definition ? Spawn a quantum theory instead

I wish that the articles on quantum theories were more clear on terminology, so that it is more clear what is a subset of what. The lead section should make it clear what quantum mechanics is in relation to quantum field theory, quantum electrodynamics, and quantum physics in general. In general, if several meaning are attached to a word, the lead sections should discuss the various meanings, and which is retained in wikipedia. The articles should then be consistent with these definitions.

I see the following inconsistencies:

  • quantum mechanics was said to be a subset of quantum field theory in the lead section of quantum mechanics, while the introduction section of the article suggests that (relativistic) quantum mechanics is synonym with quantum field theory. I have now changed the lead section to distinguish the 2 uses of the "quantum mechanics" words
  • if (relativistic) quantum mechanics is a synonym of quantum field theory, as the introduction section says, shouldn't the two articles be merged ? Why does the "quantum field theory" articles says that it is the application of quantum mechanics to fields ?

I see different options here:

  1. consider that "quantum mechanics" has 2 meanings. We would thus split / merge the current quantum mechanics page into "quantum field theory", and a new "non-relativistic quantum mechanics". The "quantum mechanics" page would then be a disambiguation page with links to both articles.
  2. consider that "quantum mechanics" has 1 main meaning, as a synonym of quantum physics or quantum field theory. In that case, I'm not sure how to position it compared to quantum field theory: shouldn't the article be merged with quantum field theory ?
  3. consider that "quantum mechanics" has 1 main meaning, as a synonym for non-relativistic quantum theory. I'm not sure this is really the most common meaning though. If it is, then we should clearly say it in the lead section of the quantum mechanics article, and change its "introduction" section.
  4. We could also use the otheruses4 template to say :"This article is about non-relativistic quantum mechanics. For relativistic quantum mechanics, please see quantum field theory". This is the option I prefer. We should then need to make sure that the article discusses non-relativistic quantum mechanics only.

Whatever we choose, there would be some work to verify that the use of the 'quantum mechanics' word is consistent throughout wikipedia. I have added the merge tag to help resolve this issue. Pcarbonn 06:03, 29 August 2006 (UTC)

Quantum mechanics and quantum field theory are different subjects and are taught as such at colleges/universities. QM is non-relativistic, the fields are not quantised and the particle number is fixed. In QFT all these restrictions are lifted. --Michael C. Price talk 08:04, 29 August 2006 (UTC)
So, you choose option 3 or 4, is that it ? Pcarbonn 20:50, 29 August 2006 (UTC)
3, although an important qualification is that "quantum mechanics" means "non-relativistic, classical field quantum theory". --Michael C. Price talk 21:10, 29 August 2006 (UTC)
Disagree: I do not approve of a merge. They are not the same thing. Waxigloo 18:48, 29 August 2006 (UTC)
So, which option do you choose ? Or you don't see a problem with the lead section and the last paragraph of the "introduction" section? Pcarbonn 20:50, 29 August 2006 (UTC)
Sorry; I forgot to say-- I think I agree with option 4. Limiting this article to non-relativistic QM and putting a link at the top for QFT seems to be the most informative and accurate thing to do.Waxigloo 00:59, 30 August 2006 (UTC)

Thank you for your feedback. I agree that a merge with quantum field theory does not make sense, so I removed the tag.

Reason for the split tag: In addition to the proposals above, I propose to create a quantum theory article, and move some of the general content of the quantum mechanics article to it (I suspect that some statements made in the quantum mechanics article apply to all quantum theories).Pcarbonn 06:16, 30 August 2006 (UTC)

What do you propose: that "quantum theory" includes "quantum field theory" and "quantum mechanics" plus some other stuff? --Michael C. Price talk 07:41, 30 August 2006 (UTC)
yes, indeed, it would be an overview of all quantum theories, and could explain some common features of them (eg. duality of wave and particles). I've created a stub already (see quantum theory). Alternatively, the article could be called quantum physics. I suspect that some people (and the current version of the article) use "quantum mechanics" to mean "quantum physics" in general, for historical reason (quantum mechanics was first, right ?). Hence the confusion. Pcarbonn 11:04, 30 August 2006 (UTC)
Sounds a good plan. I suggest that quantum theory redirect to quantum physics (or vice versa) -- ah I see you're already done that. Keep the article brief (as it is already) and have QM, QFT, etc as main articles within. --Michael C. Price talk 12:02, 30 August 2006 (UTC)

Religious objections

I don't think the content should be removed. Also, I think the reasons for removing it is false.

After the revert, I'm going to add a ref to what Hawking thinks on the subject of Einstein's "dice" quote.

I think it very much does belong here. Quantum Mechanics has it's opponents. And those reasons are valid reasons. Some of those reasons are religious. I'm a religious man myself, I put the section in on Miracles, because I'm actually reading the book now. Contrary to C.S. Lewis, I believe in quantum mechanics, almost religiously so. But I think that the other viewpoints are important to providing a NPOV. McKay 23:31, 18 September 2006 (UTC)

The Einstein quote, which is often misused and misunderstood (as it was here), is not a "religious objection" that Einstein had. I have even seen arguments that Einstein was not even all that Hell-bent on the necessity of determinism, and that that quote has been played up beyond all fairness proportional to the seriousness with which Einstein said it, and the stock he put in it. But we can assume he meant it: i.e., QM is incomplete because he felt the universe ought to be deterministic. Fine.
But Einstein was some sort of pantheist-thingummy, if I have understood him correctly. He was certainly not a dogmatic believer in any religion (on the contrary). So really, while the "dice" quote does represent some of the reservations he had about QM, they are reservations he had on aesthetic grounds, and from his sharp instinct for physical truth, not religious inclinations. There is no way that it can be accurately termed a "religious objection".
Note that I am not disputing that Einstein said the "dice" thing (so simply providing links to quote sites is unnecessary) - I am disputing that he meant it as a "religious objection". Byrgenwulf 06:24, 19 September 2006 (UTC)
Yes, Einstein was not Jewish (except by heritage). His religous beliefs were not judeo-christian. But he did have religous beliefs. saying "he had reservations on atheistic grounds" is false. I will admit that this quote is oft used incorrectly. But not in the manner in which you speak. It is oft used to establish that he was Jewish, or Christian or something. He did not believe in this manner, but he did "believe in Spinoza's God who reveals himself in the orderly harmony of what exists, not in a God who concerns himself with fates and actions of human beings." His statement that he disliked QM because he felt that it was out of the orderly harmony of the universe, is most definitely a religous statement. Without further evidence that it wasn't religous grounds, I think that your claims that it wasn't religious is dubious. McKay
About the "religious objections" section in general, then...I do agree that giving coverage to all viewpoints is important, of course. But, it should be remembered that C.S. Lewis was a professor of English, not of physics. He happens to be a real scholar, one for whom I have some respect, even; but by adding English professors' criticisms of things like Heisenberg's uncertainty principle, I very much fear we are opening the flood gates for other people to come and add their own particular "religious objections" to QM, which will no doubt also be objections raised by non-experts, and in the end the article will be bogged down by this. The bottom line is that people have "religious objections" to all forms of science, and QM is no exception; the "religious objections" to QM that I have seen are not even taken as seriously, as, for example "intelligent design".
Is every science article now to include a "religious objections" section? And "objections" from what religion? All the religions that "object"? Just how respectable do the "objections" have to be, before they can be included? For I very much doubt that Prof. Lewis knew exactly what he was talking about, and was rather just deciding what he thought the scientists meant by "Heisenberg uncertainty" - but an English professor, no matter how respectable, is simply not qualified to make pronouncements like that, I don't think. Byrgenwulf 06:24, 19 September 2006 (UTC)
I would say that if the religous objections are notable, then they should be included. Some Joe Schmoe's comments are not notable, but Prof. Lewis's, I would claim are. Sure, his claims were objections to what he thought scientists meant, but according to the book, he was actually correct in what he thought that scientists meant. He was opposed to the indeterminstic nature of the universe. Which is basically the point of Quantum Mechanics. Evolution has a religious objections section. While he is an "english professor" he is also a popular religionist. What he says on the matter of religion is notable. And he had a religious objection to QM. That's kinda like saying McKay 14:04, 19 September 2006 (UTC)
What Lewis said is notable in Lewis' article. If Lewis were famed for having objected to Heisenberg's Uncertainty Principle (or, more specifically, claiming it is merely an epistemic limitation on human beings but not an indicator of how the world "really is"), then it could be included here. But that isn't what Lewis is noted for, either: does the Lewis article have a section on "how quantum mechanics differs from Lewis's ideas on the world"? No. The exact interpretation of Heisenberg's Uncertainty Principle is also a far more subtle and intricate matter than simply dismissing it as "a limit on how accurately humans can know the world", because a statement like that carries a host of implications for how the rest QM is viewed, but which are not properly worked through in the article as it stands, so the matter is left dangling, a little like your post above.
Also, the "indeterministic nature of the universe" is not "the point" of QM. "The point" of QM is that it is the best theory of motion that we humans have at the moment.
Here's an idea. In the "philosophy" subsection of the article, whether the question of determinism is discussed, why not include a sentence like "Some Christian writers, such as C.S. Lewis (reference), share the view that the QM is incomplete, because notions of indeterminism do not agree with their religious beliefs"? That way, the point is covered, in such a way as Lewis is cited as one key example, but it doesn't open the gates to infinitely many more people making the same point and bogging down the article in unnecessary ancillary discussion. Byrgenwulf 14:48, 19 September 2006 (UTC)
I like that suggestion. I still think that Einstein's should be similarly included as well. But this is a good start. McKay 06:14, 21 September 2006 (UTC)
OK, let me try to clear some things up here. Lewis' objection is not a "religious objection": it is a philosophical objection, but the philosophical position which Lewis adopted stems from his religious outlook. Einstein's God/dice quote is not a religious objection either, because the philosophy of Spinoza (or more generally a belief in pantheism and cosmic order) is not a religion.
Also, Einstein was not "objecting" to quantum mechanics. QM works: we know this because we are writing an Internet-based encyclopaedia, which uses technology based on quantum mechanical principles (like electron tunneling). I cannot speak for Lewis in this regard, but from what I know of him he was not a complete fool, so I don't think he was actually "objecting" to QM either.
The real question here is whether QM is a complete theory or not. Einstein (and apparently Lewis) felt that it was not; although Einstein relaxed his objections later in his life. It is also a question of the philosophical interpretation of the uncertainty principle. These are not religious in nature, and nor are they real "objections" to quantum mechanics: they are objections to particular understandings of what quantum mechanics is.
Religious beliefs may have inspired Lewis' comment, and so did Einstein's personal philosophy inspire his, but it would be grossly inaccurate to class comments of these sorts as "religious objections to quantum mechanics".
I trust my recent revision will be acceptable. Byrgenwulf 17:04, 21 September 2006 (UTC)

The footnote [2] right after the comment about lewis leads to a hawking page that doesn't reference lewis. The citation should be to one of lewis's books, probably Miracles chapter 3. This needs to be fixed.


Wow. The paragraph in Lewis' book, Miracles, that sparked this discussion of Lewis has been terribly misunderstood.
First, there is the idea that his philosophical objection to QM stems from his religious beliefs. That is ridiculous. Simply notice that the pages preceding this paragraph of discussion were dedicated to constructing an argument against naturalism (material monism) based on QM. Lewis had just finished drawing philosophical implications of QM that supported his religious beliefs. That would all be very pointless if Lewis felt his religious beliefs negated the possibility of QM.
This brings us very nicely to the second misunderstanding, which is that Lewis is even definitively objecting to QM. He's not even so much objecting to QM as he is expressing his reservations over putting much stock in his argument from QM. Let's look at the paragraph.
There are actually two "objections." This first of these objections is the one cited previously, that the motion of particles is not random and lawless but merely incalculable. Read more carefully. At best all he is really saying here is that his philosophical sensibilities, so to speak, lend him to wonder if this so-called objection is actually what experts really mean by their theories. (Note his humility). My best guess as to what his philosophical ground for this reservation actually is is that QM possibly undermine the law of causation's implication that an effect cannot exceed its cause, that order can't spontaneously arise from chaos. However, this is purely speculative on my part. Hey, I like exploring possibilities. Sue me.
The second objection made is not even itself philosophical but practical. We've seen theory topple theory, only itself to be soon toppled. The fickleness of science seemed to Lewis good reason to not put all of his eggs in the quantum mechanical basket. This apprehension is one that fades in time as QM prevail.
Thus, it is obvious that Lewis did not propose any substantive objection to QM. He is simply disowning his previous argument, as he said he would at the outset of his discussion of QM (I'm aware that Lewis presents his previous argument in a way that suggests it is not his, but he doesn't cite anyone else). However, in Lewis another issue is raised that I'm interested in. Aside from philosophy waged against QM, what about philosophy that follows from it. One criticism of Lewis is that he was an English professor offering his opinion of physics. However, he offers his understanding of QM and then draws out his philosophy accordingly. Such is the work of philosophers. Physicists would be very helpful if they would temper us non-experts' understanding of these physics, rather than trying isolate each discipline from one another.
I encourage you to read Lewis' argument against naturalism from QM, if for no other reason than because it's fairly intriguing. Essentially, it goes as such:
(1)Naturalism claims that nature is a systematic totality and every event within her "interlocks" with everything else, including the movements of particles. There is nothing beyond her--no doors to be opened.
(2)Apparently these particles don't move in accordance with the general laws of nature, but rather move randomly and indeterminately. The determinate laws of motion we observe are actually normative renderings of an underlying sea of randomness.
(3)This indeterminate realm cannot be integrated into the naturalist's understanding of nature. QM are antithetical to the naturalist understanding of nature as systematic. The random motion of particles is not itself natural, but rather sub-natural, admitting something other than that which is natural.
(4)Naturalism collapses if all of nature's events arise from what is subnatural. The possibility of a supernatural is then unscathed by such a crippled philosophy.
So now I ask what someone well-studied in QM would have to say about this line of thought, even though I've completely digressed from the original topic. Progress can't be stifled by topics, you know. Okay, that's just an attempt at justifying my bringing up of what I'm interested in ...
Stephen Howard 06:09, 18 October 2006 (UTC)
Altered religious to philosophical per Stephen Howard. --Ancheta Wis 10:17, 14 December 2006 (UTC)

Weinberg quote

Let me repeat a quote from Steven Weinberg with which, in my experience, at least most field theorist and experimentalists agree.

Physics Today, April 2006, "Weinberg replies", p. 16,

... but the apparatus that we use to measure these variables—and we ourselves—are described by a wave function that evolves deterministically. So there is a missing element in quantum mechanics: a demonstration that the deterministic evolution of the wave function of the apparatus and observer leads to the usual probabilistic rules [Copenhagen interpretation].

QM, as a microscopic theory, is fully tested and is deterministic, in the sense that whenever it is possible to do an unambiguous and purely quantum mechanical calculation of how a something evolves, QM always gives a unique and correct state vector. There are empirical rules, that have not yet been fully justified theoretically, for using classical approximations in quantum experiments. So one can say that it is intuition and classical physics that introduce the probabilities into QM and not the theory in isolation.

It is a matter of choice whether to take the state vector, that we cannot directly observe, as reality or to insist that reality must have a direct correspondence to our intuition and perceptions. It is the nature of physics that its concepts tend to evolve away from intuition and direct experience, so to me the former is the more obvious choice.

Some, such as Roger Penrose, and many Wikipedia editors still believe that wave function collapse is a fundamental process that goes on in nature. My view is that this is a sort of "quantum Lamarckism" that accepts the results of QM without really accepting its content. David R. Ingham 21:58, 19 October 2006 (UTC)

Back to Einstein

It seem that what he was objecting to was QM with the Copenhagen Interpretation, as that was all that was available? In that case, he won his point with the EPR paper, if my vague understanding of the Copenhagen Interpretation is right. David R. Ingham 15:30, 22 October 2006 (UTC)

"first quantized" in the first pagagraph

Roger Penrose in The Road to Reality points out that the term "second quantized" is confusing. That makes " first quantized" too misunderstood to be in the first paragraph. David R. Ingham 05:35, 30 September 2006 (UTC)

First paragraph

The present first paragraph makes me wish I had been more attentive to my watch list. QM is a specific theory (Schrödinger and Heisenberg) that includes whatever are meant by first and second quantization. It has relativistic and non-relativistic forms. The current relativistic form is called quantum field theory. It is not just a replacement for classical mechanics, but for all classical physics, including E & M. The only other quantum physics that I know of is "the old quantum theory", which may still be used as an approximation. David R. Ingham 05:51, 30 September 2006 (UTC)

I think I catch what you're saying, but I'll bet noone understands better what you mean than you, perhaps you should be WP:BOLD, and make the change yourself. If someone doesn't like it, it will get reverted, no harm done. Please, make this article better. McKay 05:58, 30 September 2006 (UTC)

I reverted to the best version I could find in the history, Revision as of 23:25, 16 June 2006 by Keenan Pepper. The "first quantization" idea is not appropriate to mention here. "Second quantization" means the use of raising and lowering operators to account for particles appearing and disappearing. This happens if QFT, but it also happens purely within the non-relativistic many body Schrödinger equation. When one describes a solid or a nucleus with the Schrödinger equation, phonons (particles of sound, called vibrational excitations in nuclear physics) appear as collective behavior. These are created and annihilated the same way that photons are in quantum electrodynamics. Penrose says the term "second quantization" is confusing.

Secondly, I have never heard the term QM used anywhere else to single out only non-relativistic quantum physics, excluding QFT. Schrödinger and Heisenberg knew that the real world is relativistic, but did not yet see how to do relativistic quantum calculations, which is well known to be quite tricky. David R. Ingham 19:48, 30 September 2006 (UTC)

See how 1st, 2nd and 3rd quantisation are defined at quantum theory. --Michael C. Price talk 03:31, 1 October 2006 (UTC)
The Dirac and Klein-Gordon equations are relativistic quantum mechanical model, that is not a QFT, but simply the tree-level result of QED. Relativistic QM and QFT are not necessarily the same thing.Jameskeates 11:16, 2 November 2006 (UTC)

wave functions or wave funciton in the introduction

Penrose makes a big issue of the fact that a state is described by a function of the coordinates of all the particles and not by a wave function for each particle. This is how the extra variable that describe quantum entanglement come in. David R. Ingham 06:03, 30 September 2006 (UTC)

Theory section

"probability distributions" is mentioned too early. These issues are related to classical approximations rather than to quantum theory proper. David R. Ingham 06:20, 30 September 2006 (UTC)

All over the place...

I think we need a page like History of quantum mechanics...Thoughts? --HappyCamper 02:00, 7 October 2006 (UTC)

Yes it is a large subject and different people are interested in the theory itself and its history. David R. Ingham 21:09, 19 October 2006 (UTC)

AfD raised on Quantum theory

If you have view on this please go to Wikipedia:Articles_for_deletion/Quantum_theory and cast your vote. --Michael C. Price talk 06:02, 20 October 2006 (UTC)

Removed "electron should be thought of as being spread out over space"

That statment was wrong. End of story Kevin aylward 24th Oct 2006


Spread out electrons

"It should be stressed that the electron itself is not spread out over such cloud regions. It is either in a particular region of space, or it is not."

Is this really correct? How can single photons interfere with themselves, then, as they do in two-slit experiments? Also, it seems to conflict with the following -- from Physics Web:

"Quantum particles such as electrons can be in a superposition of two or more quantum states. This means that an electron can, for instance, be in two places at the same time." (from http://physicsweb.org/articles/news/4/1/7)

I'm just a lowly English grad student, so I don't feel qualified to make the change myself. But then, I've been reading about quantum mechanics since I was in the fourth grade, and I've never heard anyone suggest that, prior to decoherence, there's any such thing as an "electron itself" that "is either in a particular region of space, or... is not." There's only a quantum wave function that dictates the odds of an interaction taking place at a particular location. Am I wrong? Solemnavalanche 05:03, 6 November 2006 (UTC)

Quantization rule

I'm writing a Wikipedia article about the classical/quantum mechanical rigid rotor and need the canonical quantization rule. My first idea was to link to this article, but what a terrible article this is! In it I found for instance the following gibberish: If you take one apple, and add another apple, how many apples do you have? In other words, you have two apples. In other other words, the possible states are points in the projectivization of a Hilbert space.

I did not find the quantization rule or the time-dependent Schrödinger equation! It is really a shame that this important topic is covered so poorly. P.wormer 86.81.145.23 17:01, 17 November 2006 (UTC)

  • I'm a bit concerned that you may be proposing to violate the original research rule! You need to find a source that is better than another Wikipedia article or a response on a talk page. In any case, the phrase you quote appears to be recent vandalism, and I have removed it. --David Woolley 19:23, 17 November 2006 (UTC)
  • The addition of quantization rules or time-dependent Schrodinger equation add nothing to the understanding of the physics. For most people reading these articles, adding a bunch of equations is NOT helpful. As physicists sometimes we forget that most people do not even understand the basics of high school algebra anymore; at least thats what ive learn from teaching in college.
these things can be looked up in any introductory text book on quantum or modern physics; they should have been one of the first things taught. Often times they are listed at the back cover or appendix for easy referal. --Blckavnger 21:10, 17 November 2006 (UTC)
    • I'm a relative Wikipedia newby, but I seem to remember to have read in one of the help files that the whole spectrum of knowledge is to be covered in Wikipedia: from high school kids to postdocs. They all should find something useful. Anyway some of the existing math articles do have a very high level. If Wikipedia should not cover what is in textbooks, then most of the science articles that I've seen so far can be deleted.
    Further I wonder what you mean by 'understanding physics' when you say that knowing/being able to understand the time-dependent Schrodinger Equation does not add anything to this understanding. Do you say the same about Newton's second equation? Or any other mathematical description of physics?
    P.wormer 12:06, 18 November 2006 (UTC)
      • Actually, for an overview article, like this, there should be nothing in it that is not in a textbook! For a deeper level physics article, there shouldn't be anything that isn't in a reputable physics journal. However, the textbook may be a graduate level one, and there is a need to keep the size of the article down, whilst, at the same time, avoiding using simplifications, that appear in popular science and undergraduate texts, as though they were the whole truth. -- David Woolley 17:53, 19 November 2006 (UTC)
My main concern is someone is using Wikipedia as a reference for scientific research, as was the original discussion; but i see i wasnt making this clear. Maybe in the future this may become acceptable, but i would consider this unacceptable. While talking with other people in my field, they would also find this unacceptaple. Wiki should be for introductory information, especially in such broad topics as quantum mechanics or general relativity. Its in my humble opinion that more technical matter should be reserved for more specific, technical articles like say Quantum Zeno Effect or Binary Black Hole calculations.
Also, i do not believe that writing down a bunch of equations adds to the physics, understanding including F=ma. This opinion comes from my experience in teaching physics. I feel students dont quite understand the meaning behind the formula without elaboration and experience. They usually just echo back the equation to me. They usually cannot answer basic conceptually questions (i.e. if i apply a force thats twice as big as the first time, should the new acceleration by twice the original acceleration?)That doesnt mean we shouldn't write equation downs but ,I believe that for wiki we should keep them only to general and important equations. Specifically in this case, we shouldnt list all versions of the Schroedinger equation. One generic version of Schodinger is fine and i think the form of the time-dependent Schrodinger equation is not as illuminating.
But again this is my opinion; if everyone else thinks that it would be appropriate i would happily withdraw my comments. Sometimes when you get into a research area its hard sometimes to find an outside perspective. --Blckavnger 16:59, 20 November 2006 (UTC)