Wikipedia talk:WikiProject Physics/Archive August 2020

More new articles

Noticed for one reason or another:

• Krausser-Samwer-Zaccone equation (edit | talk | history | links | watch | logs)
• Minimon (edit | talk | history | links | watch | logs)
• Maximon (particle) (edit | talk | history | links | watch | logs)
• Paraphoton (edit | talk | history | links | watch | logs)

Cheers, XOR'easter (talk) 06:53, 31 July 2020 (UTC)

I'm skeptical that Minimon and Maximon satisfy the WP:GNG. It seems to be a pet theory of M.A. Markov that wasn't taken up by the scientific community. I went through the references in Maximon; Reference 1 is an article by Markov himself inside a collection. Reference 2 has two articles by other authors, but they simply quote Markov about his own work. I can't access Reference 3, but it seems to be the proceedings of a conference on astronautics. Reference 4 is in Russian, and Reference 5 is Markov's original article. In the Minimon article References 1 to 3 are all the same paper by Markov, and Reference 4 is the same article in Russian. Tercer (talk) 10:17, 31 July 2020 (UTC)

It is concerning that the {{notability}} on the first was simply reverted, without adequate referencing. WP is not the place to be coining names for things. As for the other three, IMO these should not be standalone articles, along some others; they might have a place in a list of hypothetical particles. Lamro seems to be under the the impression that any academic mention of a hypothetical particle warrants an article in WP. See here for others. —Quondum 12:00, 31 July 2020 (UTC)

I'm a bit confused about Paraphoton. Isn't this just another name for a dark photon? That's what the lead of Dark photon claims, anyway. This particle is notable enough for a standalone article. Tercer (talk) 12:37, 31 July 2020 (UTC)

Do you mean "is not"?

Originally, paraphoton was a redirect to dark photon. I don't think that the current version really makes the case that a separate article is necessary. XOR'easter (talk) 14:21, 31 July 2020 (UTC)

No, I mean "is"; there are plenty of independent peer-reviewed articles talking about the dark photon, this is enough to satisfy WP:GNG. As for the paraphoton, if it is indeed the same particle, it should just go back to being a redirect. If it's not the same thing than more work is needed to establish what the difference is and why it should be notable. Tercer (talk) 14:37, 31 July 2020 (UTC)

Ah, OK. I thought "This particle" was referring to paraphoton, which left me a little confused (coffee hadn't yet kicked in). I concur with your evaluation. The terms seem to be used synonymously (e.g., [1]), with "dark photon" being much more common. XOR'easter (talk) 15:09, 31 July 2020 (UTC)

• In the literature case a) is widely used not only for a massless dark photon but also for a very light one, which is sometimes called “paraphoton”.
• ... the only new particle included is a gauge boson which has received many names: paraphoton, hidden photon or dark photon to name but a few.

It seems to me that the paraphoton and dark photon are generally regarded as the same, even if there might be a slight distinction (massless vs. very light) occasionally. This suggests that they should be the same article, with any possible distinction mentioned in the article (if at all). —Quondum 15:46, 1 August 2020 (UTC)

A not-so-new article

• Gravitational coupling constant (edit | talk | history | links | watch | logs)

This is along the lines of a gravitational analogue of the fine-structure constant, may fail WP:GNG. Comments welcome. —Quondum 15:15, 1 August 2020 (UTC)

I have Wikipedia:Proposed deletion of this article. —Quondum 20:24, 2 August 2020 (UTC)

I hadn't had a chance to look into it until today, but I concur with your PROD rationale. XOR'easter (talk) 20:52, 2 August 2020 (UTC)

Draft:Phase space quantum mechanics

Will someone please review this draft? It is beyond what a chemist can be expected to understand. Does it rely on reliable sources? Robert McClenon (talk) 23:26, 24 July 2020 (UTC)

Could be notable, but it reads like a text book and seems inconsistent with Wikipedia style. Xxanthippe (talk) 23:28, 24 July 2020 (UTC).

There are many things that could be called a phase space representation of quantum mechanics; see Wigner quasiprobability distribution and the chapter in Peres' textbook on such things. This article seems (it is not written very clearly) to be about something more specific, but it does not express what the contribution of that more specific implementation of the "let's do quantum mechanics on a phase space" idea is. Indeed, it cites an article on the topic that is decades older than the one which it claims introduced the subject. If I didn't already know something about the topic, I'd be completely lost; as it is, I'm only mostly confused about what they're trying to explain. XOR'easter (talk) 00:00, 25 July 2020 (UTC)

The references look OK as far as reliability goes — not everyone would trust Advances in High Energy Physics, since Hindawi doesn't have a great reputation for quality, but Annals of Physics and Physics Letters A are probably solid (Elsevier is an awful corporation, but we can expect that those specific journals likely provide solid peer reviews). I haven't heard anything either good or bad about the Ukrainian Journal of Physics. My concern is that they are only lightly cited, are in some cases very recent and seem to be from the same group, apart from one that was added by someone other than the creator. Honestly, this looks like what you'd get if you told the newest grad student in your research group to write a Wikipedia page about your research. XOR'easter (talk) 00:17, 25 July 2020 (UTC)

Maybe this is an opportunity to prompt them (the primary editor) to clean up some aspects (e.g. sourcing diversity). As someone who does not understand the detail but who is able to understand a well-written outline explanation of the topic, I find that the lead is essentially completely missing an accessible outline of what is being talked about. A more accessible outline (plus diverse reliable sources to establish notability more clearly) would be helpful in assessing it. I am also particularly concerned that this looks at a glance to be largely a duplication of content of the article Phase-space formulation, including re-use of diagrams. Establishing the difference from that article should be the primary focus, not repeating much of the content without highlighting the differences; this might count against it being a clearly distinct topic. —Quondum 00:47, 25 July 2020 (UTC)

It seems in fact to be bits and pieces of the phase-space formulation article, chopped up and made less comprehensible. Phase-space formulation has a legitimate lead, decent prose, and better sourcing. New additions should start there — the topic is one that has many variations — before one tries to make an entire new article. XOR'easter (talk) 04:46, 25 July 2020 (UTC)

I Changed the focus from wave mechanics in wigner representation to a more broader, Phase-space representation of quantum state vector. More diverse references were added and eliminated some references of the old draft. The aproach of construction of Wigner function from wave mechanics in phase space still in the article, but it was considerable reduced. Torres-Vega and Wigner wave functions are the most worked but a generalization is mentioned. Phase-space representation of quantum state vector is probably a better suitable name for the article. GustavoPetronilo (talk) 06:36, 2 August 2020 (UTC)

Is there anywhere in the article a direct definition of its focus function, $\psi (x,p)$, in terms of Schroedinger's wave function $\psi (x)$, as one conventionally has for the Wigner function? The diagonal Wigner function is of course real, but the off-diagonal one is virtually never real, which is how QM interference, perturbation theory, etc, are addressed in phase-space quantization. So the last sentence of the first paragraph in the lede is pointless. Cuzkatzimhut (talk) 11:55, 2 August 2020 (UTC)

The wavefunction, $\psi (x,p)$, is constructed from a Hilbert space in phase space ${\mathcal {H}}(\Gamma )$, thus $\psi (x)$ allows complex values, even for scalar functions. By Moyal product properties $(\psi \star \psi ^{*})^{*}=(\psi \star \psi ^{*})$, so the new fucntion is real, futhermore the time evolution of the function $\psi \star \psi ^{*}$ is the Liouville-von Neumann equation in Wigner-Weyl representation, so this new function has properties of Wigner distribution. When the time independent $\psi (x,p)$ is real $\psi (x,p)$ and $W(q,p)$ are the same and we get back the Phase-space formulation. The last sentence was to made clear that wavefunction in phase space has a role similiar to the wavefunction in position or momentum space, being a amplitude for the quasiprobability Quasiprobability distribution (a quasiamplitude), as $\psi (x)$ is the amplitude of the position distrinution. This line can be removed if it is causing confusion. The construction of $\psi (q,p)$ is made in the section Symplectic Hilber space. GustavoPetronilo (talk) 14:36, 2 August 2020 (UTC)

Yes that sentence is willfully confusing, and unhelpful. But my question is not how $\psi (x,p)$ is defined as an abstract solution of a *-genvalue equation: It is how it relates directly to Schroedinger's wave function $\psi (x)$. How? The claim made is that this is not a mere graphics interface of the phase-space formulation, but a framing directly equivalent to the Hilbert space formulation. How is it defined on terms of that formulation, and where is the equivalence, without abstract aspirational linkage to the standard phase-space formulation? Cuzkatzimhut (talk) 14:59, 2 August 2020 (UTC)

You're right there is no direct definition of this in the article. But as it construct from a Hilbert space you can go from one to another via transforms like from position to momentum using Fourier transform. More specifically we have $\langle \Gamma |\psi \rangle =\int _{-\infty }^{\infty }dx'\langle \Gamma |x'\rangle \langle x'|\psi \rangle =\int _{-\infty }^{\infty }f(x'-x)\exp(-ip(x'-x)/\hbar )\psi (x)$, and $f(x'-x)$ will depend on the representation of phase space. GustavoPetronilo (talk) 15:52, 2 August 2020 (UTC)

Indeed, after correcting your formula, and precisely defining f(x-x'), specificity for the Weyl map would help a reader appreciate what is being talked about and why this is not a mere idle elaborate detour in constructing the Wigner function which furnishes the actual expected value answers. As a simple example, contrast the monumental easy calculation of section 3 of the classic Bartlett-Moyal 1949 paper with the nightmare the object you just defined might yield. Cuzkatzimhut (talk) 16:13, 2 August 2020 (UTC)

Thank you Cuzkatzimhut and all others for the help. I added more information in the Hilbert space in phase space, showed the association with the Schrödinger wave mechanics citing where the information is from, and removed the unnecessary information about complex value of the wavefunction in phase space. GustavoPetronilo (talk) 19:56, 2 August 2020

I fear you are going in circles: How is $\psi (x,x')$ related to Schroedinger's wavefunction $\psi (x)$? Flip-flopping to momentum space hardly helps. The Wigner function is a straightforward function of $\psi (x)$, possessing even an elegant expression in terms of that and *-products, but your expression is still undefined.Cuzkatzimhut (talk) 20:45, 2 August 2020 (UTC)

This is not a trivial question, in the article cited, Amorim 2019, to answer this, it uses techiniques of thermofield dynamics which has a similar doubling in the Hilbert space, using a object $\rho ^{1/2}$, there is links for the reader if it interesting then. What this aproach brings is a way to construct phase space distributions using a extended Hilbert space, where one of this distribution can be show to have the sames properties of Wigner function, we have already a indirect link from $\psi (x,p)$ to $\psi (x)$ via the Wigner function, and the Torres-Vega distribution was shown that can be associated with Husimi distribution at least for some system calculated, and as another aproach of quantum mechanics new insights in the theory can be made. GustavoPetronilo (talk) 01:47, 3 August 2020

You need not go there: Chruściński & Młodawski do the right-plugging of the Wigner function for you with a fixed reference state ψ', as the teeming crowds have been rediscovering again & again, & yet again, in the last 70 years. The point is if you chose to exploit $\rho |\psi '\rangle =|\psi \rangle \langle \psi |\psi '\rangle$ for a pure state, you are simply doing phase-space QM with one hand tied behind your back, dragging along superfluous variables you have all but completely lost control of, and no evident advantage in solving an actual problem.

I have no idea why an innocent WP reader would wish to go there, and then spend weeks digging out the really informative exposes in the literature. I assume you are familiar with the stock deformation quantization involving Wigner functions and Schroedinger wave functions , as given in standard textbooks, $W(x,p)=\psi (x)\star \delta (p)\star \psi ^{*}(x)$, sticking to the Weyl-Wigner map without adding superfluous sectors. Cuzkatzimhut (talk) 13:46, 3 August 2020 (UTC)

A very good article indeed. So is it better to change this part, Eq 17 and 54, right? With this choice $\psi (q,p)\propto W$, the Oliveira aproach becames virtually the same of the usual as the usual phase space formalism, with the normalization condition $W\star W\propto W$. In general $\psi (q,p)\star \psi ^{*}(q,p)\neq |\psi (q,p)|^{2}$, the object $f=\psi (q,p)\star \psi ^{*}(q,p)$ has the nice property satistfy the equation $\partial _{t}f=-\{\{f,H\}\}$, if $\psi$ satisfy the time dependent Schrödinger equation. GustavoPetronilo (talk) 15:58, 3 August 2020

The asked changes were made and a good and diversified number of citations are in the references, if is need more revisions before resubmission let me know. GustavoPetronilo (talk) 2:22, 20 August 2020 (UTC)

Reviewer Comment

Thank you for your comments. I have copied these comments to the talk page of the draft, and have declined the draft again. My instructions to the author are to discuss here before resubmitting. Robert McClenon (talk) 03:44, 2 August 2020 (UTC)

Elasto-plastic self-consistent modeling

Hello! I found the above article while trawling through orphan categories. Can I get some advice on whether it's notable enough to remain as a standalone (and maybe where to link to it if so), or should be merged somewhere, or should be deleted outright? Thanks in advance! ♠PMC♠ (talk) 08:31, 3 August 2020 (UTC)

It looks like it should just be a redirect. JRSpriggs (talk) 00:51, 4 August 2020 (UTC)

JRSpriggs, what would be the most appropriate target? ♠PMC♠ (talk) 13:57, 8 August 2020 (UTC)

Understandability

Is is feasible to make articles about basic physics accessible to high school students, as well as being the definitive statement that would satisfy a professor of quantum mechanics? If you did not know much about the subject and looked at an article such as Momentum, do you think that you would be encouraged to read it? JMcC (talk) 09:52, 8 August 2020 (UTC)

It looks OK to me. Xxanthippe (talk) 10:31, 8 August 2020 (UTC).

Not every high school student would be in the target audience, but it should include those who are sufficiently familiar with the related concepts of vector, mass, etc. While it is good to be addressing as wide an audience as possible, articles are intended as reference, not pedagogical explanations of concepts, and in particular it is not desirable to make it laborious to read for those familiar with the subject. If you see ways in which an article could be improved, its talk page would be the place to discuss it. Without your giving specific objections, it is difficult to know what you have in mind that is bothering you about such articles. —Quondum 16:37, 8 August 2020 (UTC)

Most physics articles should start out at a level that is accessible to a high-school student, and then get more complicated as necessary depending on the topic. In many cases, I wouldn't expect a high-school student to get past the lead section, but there often isn't much more to say at that level than that.--Srleffler (talk) 17:54, 8 August 2020 (UTC)

Our general guideline on understandability for these sorts of articles is Make technical articles understandable. In that guidance is the idea of putting the introductory/accessible material toward the front of the article. One thing we could do today is to move the History section up to the top of the article after the lead. That would also make the telegraphic heading "Newtonian" of the next section more understandable. --{{u|Mark viking}} {Talk} 18:06, 8 August 2020 (UTC)

I'd rather resolve the dispute tag on that section before making it more prominent, and I'm not entirely sure that getting into historical minutiae is the best opening act either. The general advice of putting the introductory/accessible material early, writing one level down, etc., is good; applying it here will just be a bit finicky. XOR'easter (talk) 19:06, 8 August 2020 (UTC)

Be careful with that. In science articles, history is often of lesser importance. It typically should not be the first thing the reader sees after the lede. The scientific concepts—as currently understood—are much more important than the history of how we got here.--Srleffler (talk) 23:42, 8 August 2020 (UTC)

Blanet

• Blanet (edit | talk | history | links | watch | logs)

Looks too soon to be wiki-notable. XOR'easter (talk) 20:44, 8 August 2020 (UTC)

Agreed – this is clearly still only at the "science tabloid" stage. I'm not sure it does any harm being there as long as it remains tagged (I don't expect it to be the kind of thing that attracts much WP:OR cruft). Another possibility is if there is a general article describing this kind of thing (hypothetical and real astronomical objects), it could mention this and serve as a target of merge. —Quondum 12:24, 9 August 2020 (UTC)

You're probably right that it's not particularly harmful as far as stub pages go. XOR'easter (talk) 06:02, 10 August 2020 (UTC)

Potentially inappropriate pictures in electricity and magnetism articles

Hi, in the Electric field and electrostatics articles, among others, there are pictures of a cat with Styrofoam peanuts stuck to it and, just today, a girl with hair pointed up when touching an electrostatic generator. I removed the same cat picture from the electric field article as its caption began as "proof of the electric field" and I generally thought it to be inappropriate for the article. It is similar to taking a picture of a baby laying in a crib and offering it as proof of evidence for the gravitational field. The electric field is a mathematical model and I do not see any understanding can be gained from examples like these, which can be explained without reference to the electric field. More importantly, I feel they actually detract from the articles, making them less professional and more distracting. Others disagree, however, and the cat picture I took down was quickly replaced with the picture of the girl touching the electrostatic generator, so I wanted to ask you all before removing other photos.Footlessmouse (talk) 21:23, 13 August 2020 (UTC)

The caption began Evidence of an electric field, not proof of the electric field [2]. I do not think either picture seriously detracts from the article, but that is perhaps a matter of taste. XOR'easter (talk) 22:15, 13 August 2020 (UTC)

Yes, please drop by and give us an opinion. It's at Talk:Electric field#Removal of cat picture. Thanks --Chetvorno^TALK 22:44, 13 August 2020 (UTC)

I botched that memory, my bad. I could have sworn it used the word proof. Anyways, I am okay with being outvoted, I am just strongly convinced of my view on the subject. Footlessmouse (talk) 22:56, 13 August 2020 (UTC)

A rephrasing of this question: is it okay for me to start adding pictures such as a couple of schoolchildren on a teeter-totter as evidence for torque on the torque page? A baby sleeping in a crib as evidence for a gravitational field on the gravitational field page? A picture of a motorcyclist not falling off the bike as evidence for the conservation of angular momentum? A small child playing with a handheld gaming system is evidence for chemical potential? A young girl breathing normally is evidence of the ideal gas law? A picture of some young boy throwing stones into the ocean as evidence of tectonic plates and their dynamics? There are a near-infinite number of trivial examples for how physical effects effect everyday life, but the vast majority of them are not enlightening.Footlessmouse (talk) 00:34, 14 August 2020 (UTC)

How to use physics (static electricity) to torture a cat with styrofoam "peanuts".

[Added cat photo at right.] JRSpriggs (talk) 01:21, 14 August 2020 (UTC)

An example how electric fields have an effect in everyday life is fine I think. We do have a hammer and feather falling down for gravity. The angular momentum article has a gyroscope as first image and a figure skater later in the article. I don't see the problem you see. --mfb (talk) 03:51, 14 August 2020 (UTC)

Footlessmouse: I suggest you read Wikipedia:Do not disrupt Wikipedia to illustrate a point.--Srleffler (talk) 03:55, 14 August 2020 (UTC)

Thank you for that note, I have read the said page, which I previously did not know existed, and have come to the determination that nothing there applies to this conversation. Why did you bring it up, could you elaborate? No edits have been made, I mentioned hypothetical edits that no one has any intention of making, therefore no disruption has taken place, as per the Important Note section of that page. Could you elaborate on how you think this disrupts Wikipedia and what policy it is that we should be following and the talk page for said policy where this conversation should be happening? My understanding is there is currently not a policy regarding this very niche discussion and I was wondering how the rest of the community felt about it.Footlessmouse (talk) 04:23, 14 August 2020 (UTC)

I found Wikipedia:Manual of Style/Images, but it does not solve the dispute, though maybe this conversation should have taken place there. Either way, I believe I hold a minority opinion here, so I will drop it. Thank you all for your input. Footlessmouse (talk) 04:35, 14 August 2020 (UTC)

Physics education in the United Kingdom

• Physics education in the United Kingdom (edit | talk | history | links | watch | logs)

New article, subject looks notable, needs work. XOR'easter (talk) 21:32, 15 July 2020 (UTC)

Lotta work, given there is only one ref and a lot of statements. Physics education needs some work as well. If we can't find enough sources it should probably be merged into that article. Primefac (talk) 22:32, 17 July 2020 (UTC)

The one source is pretty comprehensive. Xxanthippe (talk) 22:55, 17 July 2020 (UTC).

Added a couple of references to some of the statements Careless Torque 16/08/20 —Preceding undated comment added 15:48, 16 August 2020 (UTC)

A Brief History of Time (S. Hawking book)

I was looking through articles with the Expert in Physics Needed template and I found an easy one in the article on Hawking's book A Brief History of Time. The chapter 9 section of the article has said template in place. I have reworked the whole section, after renting the e-book and quickly reading the chapter. I also started a discussion on the talk page with details on what changed and why, but it does not yet have any responses, so I am hoping to get some guidance from here. Please let me know if further improvements can be made and what, if anything, needs to be done before the expert in physics needed template can be removed. Footlessmouse (talk) 21:21, 15 August 2020 (UTC)

Although I would not call myself an expert, that section is on par with all the others, and accords well with my memory of the book (somewhat stretched by now, as I last read it not long after it was published ). IMO, you should remove the template. —Quondum 17:01, 16 August 2020 (UTC)

Thank you @Quondum: and @XOR'easter: for contributing to the article and for your comments. I am also probably not an "expert in physics", I'm not sure what it would take to qualify. I believe it is much better now, especially after Quaondum's and XOR'easter's edits. I will leave this discussion for now, in case others wish to contribute, but I assume that we can just take down the template in a week or so, given everyone is on board. Thanks! Footlessmouse (talk) 22:54, 16 August 2020 (UTC)

Isotopes in medicine

I'll pick up on this stub over the next few weeks and add a couple more sections/ info in it. Working draft is in my sandbox here.Careless Torque (talk) 22:47, 20 August 2020 (UTC)

You may consider splitting the article into sections based upon pharmacological or imaging use, as they are radically different topics. There is also not much information on there about what the isotopes are used for in the fist place. For the medical imaging compounds, this shouldn't be too difficult to give an overview of, and will go a long way in explaining the relevance of the topic. It may help to add some references to standard medical physics textbooks. Also, nuclear medicine and medical imaging have their own pages, which already cover a lot of the content that should be in this page. The nuclear medicine article even has a table of common isotopes used in nuclear medicine. Just friendly suggestions. Good luck! Footlessmouse (talk) 00:25, 21 August 2020 (UTC)

Thanks a lot for the suggestions Footlessmouse - I'll make the changes in the sandbox rather than main article for now but definitely splitting it as you suggested. Careless Torque (talk) —Preceding undated comment added 23:06, 21 August 2020 (UTC)