Talk:Applications of quantum mechanics

linking edits

I have revised some new link edits, for the following reasons.

• I think it is customary to capitalize the article title in a link even if the displayed text is uncapitalized.
• The link to de Broglie–Bohm theory would be in my judgment inappropriate. The reason is that de Broglie's theory is radically different from what is discussed in the article entitled de Broglie–Bohm theory.

What is discussed in the article on de Broglie–Bohm theory in my opinion is not radically different from quantum mechanics, and is often considered as a form or re-interpretation of quantum mechanics. So I have loosely regarded it as covered under the heading of quantum mechanics. de Broglie had a radically different theory of his own, from which Bohm took some elements, but still it remains the case that de Broglie's theory is not the same as what is discussed in the de Broglie–Bohm article. It is a radically different theory, and is not widely studied, while the Bohm theory is widely studied.

So far as I know, there is no adequate discussion of the de Broglie theory in its own right in Wikipedia. That is why I did not link to the de Broglie–Bohm article, and I still think that was right.

Many articles assume, without apparently having read the literature carefully, that they can guess what is in de Broglie's theory, but I think they assume wrongly. For example, recently I had occasion to quote word for word from de Broglie in Wikipedia, with proper referencing, but was told by an editor who knows all about it (i.e. his actions suggest that he feels that doesn't need to read the references or check the literature) that what de Broglie actually wrote was nonsense. When I persuaded that editor to read the reference, he had no more to say.Chjoaygame (talk) 08:00, 27 November 2014 (UTC)

reasons for undo of good-faith edit

I have undone a good-faith edit for the following reasons.

• The edit was out of fit with the logical structure of the article. It put detailed argument in the lead, whereas the rest of the lead was summary, with detail only in the body of the article.
• The cited source was nowhere near neutral enough or well enough conceived and argued to be considered reliable for such weighty and general questions.
• Indeed the cited source was more along the lines of advocacy with special pleading, rather than being a well-researched and neutral piece of physical reporting. And the edit suffered from the same defect.

If more information about de Broglie's work is to appear in this article, it should be in a new section in the body of the article, not in the lead. Moreover it should be very soundly based in ordinary physics, as opposed to the special advocacy, even enthusiastic propaganda, of the undone edit. It is not obvious that Bohm's work properly represents the de Broglie approach, even though many works of special advocacy claim that, and Bohm's work is based on de Broglie's to a significant extent. A suitable new section should be based directly on de Broglie's writing and secondary sources that report on it for its own sake, as opposed to being an account of Bohmian theory insofar as that purports to represent de Broglie theory.

The bar is high here. This article is very general, and needs fitting soundness and neutrality of literature survey and physical understanding. This article is a kind of summary disambiguation page, as opposed to an argumentative or presentational page.Chjoaygame (talk) 12:06, 20 December 2014 (UTC)

Redirect to quantum mechanics

From the beginning of Wikipedia until November 2014 "quantum physics" was a redirect to quantum mechanics. The first sentence of the quantum mechanics article says "Quantum mechanics (QM; also known as quantum physics, or quantum theory) is a fundamental branch of physics...". This new article seems to be nothing more than a content fork which is discouraged by wikipedia guidelines for a number of good reasons. I propose that it be redirected back to quantum mechanics, with any content that doesn't duplicate existing articles moved across. Djr32 (talk) 17:51, 26 December 2014 (UTC)

Thank you for your considered response. You offer the pejorative comment "nothing more than a [[Wikipedia:Content forking|content fork]".

I created this article because in the article entitled Quantum mechanics is, as you say, the parenthesis "(...; also known as quantum physics or quantum theory)". The terms are not synonymous though that parenthesis suggests to the novice reader that they might be. It would take considerable reading for the novice reader to disentangle the confusion so created. Considerable reading would be required for the novice reader to learn that quantum mechanics is not the only kind of quantum physics. Much effort is expended trying to reconcile the quantum mechanical formalism proper with ordinary physical content such as Niels Bohr considered necessary. The novice reader may likely benefit from a brief explicit general guide in this area, to help him deal with the detail that is found in the separate articles.

The old quantum theory is fundamentally different from quantum mechanics, which again is fundamentally different from quantum field theory. The distinct status of de Broglie theory is in my opinion hard to be sure about. There are three or four separate articles, that are not mere specializations of each other, to which the present article gives links. The reader can benefit from a guide to which one he wants.

To say or imply that the old quantum theory, quantum mechanics, and quantum field theory are the same thing is to commit a fallacy of confounding or conflating distinct entities.

Therefore I think this article is properly speaking not a fork.

One might very reasonably argue that the present article entitled Quantum mechanics properly speaking an article about quantum physics in general. In that case it would be reasonable, on one possible interpretation, to call that article also a fork, and thence to ask for its merging into the "real" articles. Alternatively, one could argue for calling a spade a spade, and change the title of that article to Quantum physics. Not that I am recommending any of these.

Reading the article entitled Quantum mechanics one finds the sentence "The earliest versions of quantum mechanics were formulated in the first decade of the 20th century." This claim is unsourced and is deeply misleading. It seems more like an attempt to editorially brainwash the reader than to encyclopaedically inform him. The discovery of quantum mechanics was dramatic, a real quantum jump in concept. It is true that quantum physics began to be worked on in the first decade of the 20th century, but this statement is not the same as implying that the Planck–Einstein work was a "version" of quantum mechanics. That implication is simply misleading or inaccurate or a piece of spin or propaganda for some curious history-erasing agenda. True, history is written by the victors, but Wikipedia is an encyclopaedia, not a version of history to be entirely controlled and patrolled by the victors. Even if it were, it is not clear between quantum mechanics and quantum field theory who exactly are the victors. Nor is it of much concern to Wikipedia.

The article entitled Quantum mechanics feels the need to talk about "the old quantum theory" in so many words. That means it is not synonymous with quantum mechanics or indeed with quantum physics.

The article entitled Quantum mechanics says "When it was found in 1900 by Max Planck that the energy of waves could be described as consisting of small packets or "quanta", ..." This shows that it isn't infallible, and that it should not dictate what appears in other articles. Max Planck in 1900 found no such thing, as I suppose you well know. Again, the article on quantum mechanics in its history section says that "Scientific inquiry into the wave nature of light began in the 17th and 18th centuries, when scientists such as Robert Hooke, Christiaan Huygens and Leonhard Euler proposed a wave theory of light based on experimental observations." Newton made the primary and most fundamental quantum discovery, that a pure-coloured beam from a prism, when put through a further prism, comes out as a beam with the same pure colour. Newton said that light seems to wriggle like an eel, to account for diffraction at an edge. He proposed a corpuscular theory, which was eventually vindicated, largely by Einstein. But there is no mention of this study of light by Newton in that article. Just another example that the article is not infallible and should not be taken as a guide for other articles.

It takes considerable reading of the literature, in addition to what one otherwise finds in Wikipedia, to work out the simple distinctions that are drawn concisely in the present article. In the longer articles it would be hidden and buried far beyond the novice's finding. We are enjoined to be bold, so some discouragement, especially on such a basis as the present proposal, should not cripple or bind us into making it hard for the reader.Chjoaygame (talk) 06:16, 27 December 2014 (UTC)

Thanks for raising this at QM as well - I think it would be best to have the discussion once, though I'm not sure which talk page would be better to have it on.Djr32 (talk) 20:25, 27 December 2014 (UTC)

Yes, it's not quite clear where it will go.Chjoaygame (talk) 00:25, 28 December 2014 (UTC)

You might not like the use of the term "Quantum Mechanics" to encompass all of these topics, but I'm afraid that you will have to take that up with better minds than me, for example Steven Weinberg whose Lectures on Quantum Mechanics range from a historical introduction covering the Planck formula and Bohr model to QED, and other textbooks published by well known university presses that cover a similar range of topics, etc.Djr32 (talk) 20:25, 27 December 2014 (UTC)

True, a text on quantum mechanics is likely to discuss the historical generation of the subject, and may extend to quantum field theory. I think we don't need to follow the loosest usage that occurs. Rather we should seek the best, clearest, and most precise that is widely found. The title of a book is not always a precise guide to its content. To find the meaning of words, one is best to read the content. In my present library are several dozen texts that I have listed as on quantum mechanics. I have another list for texts on quantum field theory. It is usually easy to decide to which a new one should go.

You give two links.

Weinberg has written the quantum mechanics lectures that you indicate, as well as his three-volume work on quantum field theory. Reading the preface of his 2013 Lectures, I think he distinguishes between quantum mechanics and quantum field theory. I think it would confuse and even mislead the general reader to conflate those terms as ones the present Wikipedia article entitled Quantum mechanics. The subject matter of the Lectures is largely different from that of the three-volume work. I think Weinberg mainly makes the distinction that I am arguing should be made by Wikipedia. I count him as an example in favour of my position.

I don't have right here a full copy of Commins' text, the top one on the advertisement page of your link. I can just now however quote from some of its advertising front material. "Commins examines many modern developments in quantum physics, ..." The contents list a section on "the antecedents of quantum mechanics" on page 2. There I read "... the invention of quantum mechanics occurred in a remarkably short time interval, from 1925 through 1927." On page 6 I read that "the Bohr-Sommerfeld model was ... replaced by quantum mechanics." I think Commins habitually makes the distinctions that I am arguing for, and so I count his book as an example in favour of my position.

As for the next book on that advertising page. It is entitled Quantum Mechanics with Basic Field Theory. The distinction is even in the title. Reading the chapter that is offered as an advertising excerpt, I find Desai using the term 'quantum mechanics' just as I am recommending.Chjoaygame (talk) 00:25, 28 December 2014 (UTC)

I have no idea what you're going on about regarding one of quantum mechanics and quantum field theory looking to claim victory over the other, "brainwashing" or a "history-erasing agenda". Old quantum theory certainly is a thing, but it was a step on the road to modern-day QM, so it's of historical (and pedagogical) interest. It's sensible for it to have an article of its own to cover it in more detail than belong in the QM article. It wouldn't be sensible to try to remove all of the discussion of Planck and Bohr from the article that covers Schrödinger, Heisenberg and onwards.Djr32 (talk) 20:25, 27 December 2014 (UTC)

"Move along please. There is nothing to see here."

One can include in an article on quantum mechanics a discussion of its antecedents in Newtonian mechanics and Hamilton's optico-mechanical analogy and the old quantum theory without meaning that those antecedents are part of quantum mechanics. Between a thing and its antecedents there is difference. It is misleading to try to erase it.Chjoaygame (talk) 00:25, 28 December 2014 (UTC)

To me, it is clear that there is one topic that both the existing Quantum Mechanics article and the new Quantum Physics article are attempting to cover. Creating a new article to cover the same topic as an existing article is the definition of content forking. There are a lot of issues with your new article, and the work on writing an article to cover this topic has already been done in the existing article, so I would like to change the new article back to a redirect before we spend a lot of time on it. I'm fairly neutral about whether that article should be called quantum mechanics, quantum physics or quantum theory. Djr32 (talk) 20:25, 27 December 2014 (UTC)

For the present, assuming you really are neutral on the title of the present article that is currently labelled Quantum mechanics, I have reverted to the redirect that you prefer. I wrote the new disambiguator on the assumption that the article entitled Quantum mechanics would be about quantum mechanics. Now I see that Quantum mechanics is not a suitable title for the present Wikipedia article that carries it. I think it is a travesty, a device to confuse the reader, a product and regenerator of muddle.Chjoaygame (talk) 00:25, 28 December 2014 (UTC)

Splitting proposal 2

Please see Talk:Quantum_mechanics#Splitting_proposal_2. Polyamorph (talk) 12:13, 7 October 2020 (UTC)

Aaaah, some old faces. Ema--or (talk) 20:32, 18 February 2021 (UTC) Alright see Strongly advocate merging with statistical mechanics there. Ema--or (talk) 21:32, 18 February 2021 (UTC)

Revamp or Remove

This article is ... troubled. I just deleted the light switch thing, which apparently sat here for 2 years without anyone calling it into question. Basically the article sources very few of its claims (and a full third of the sources are PopSci dreck) and IMO spends more time handwaving than explaining. Take the electronics section for instance:

"Many modern electronic devices are designed using quantum mechanics. Examples include the laser, the transistor (and thus the microchip), the electron microscope, magnetic resonance imaging (MRI), Global Positioning System(GPS), and computers."

No further explanation, no sources, just jumps sideways into flash memory from there. I mean, I can say anything runs on quantum mechanics, but until I actually explain how, or what I mean by that, it doesn't belong in an encyclopedia.

The "Other Phenomena" section is similarly problematic - a layperson might view it as undercutting the rest of the article. Plus the "Cryptography" and "Quantum Computing" sections are basically stubby redirects to those (bigger, better, well-sourced) pages. The more I think about it, the more I feel like there's the beginnings of an argument for a merge or deletion here. Grudsy (talk) 11:11, 3 October 2022 (UTC)