# Wikipedia talk:WikiProject Physics

WikiProject Physics
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## K-k-k-kerr Bblack Hhole

I found another instance where capitalization of redirects matters here at WP. If you type "Kerr bla" into the search box you will see both Kerr black hole and Kerr Black Hole show up as suggestions. The first redirects to Kerr metric and the second to Rotating black hole. Quite different articles.

Kerr metric has Rotating black hole in its See also section. And Rotating black hole mentions Kerr metric linked in text.

So... "Kerr black hole" and "Kerr Black Hole" ought to resolve/redirect to the same article. Which? Shenme (talk) 03:28, 30 May 2018 (UTC)

The term "Kerr black hole" is more specific than "rotating black hole", as a Kerr black hole is necessarily uncharged. I'd say that Kerr black hole and the alternate capitalization Kerr Black Hole should both redirect to Kerr metric. XOR'easter (talk) 03:43, 30 May 2018 (UTC)
Spot on, Kerr metric is the best target. --Mark viking (talk) 17:21, 30 May 2018 (UTC)
Change made. XOR'easter (talk) 05:10, 31 May 2018 (UTC)

## WikiProject collaboration notice from the Portals WikiProject

The reason I am contacting you is because there are one or more portals that fall under this subject, and the Portals WikiProject is currently undertaking a major drive to automate portals that may affect them.

Portals are being redesigned.

The new design features are being applied to existing portals.

At present, we are gearing up for a maintenance pass of portals in which the introduction section will be upgraded to no longer need a subpage. In place of static copied and pasted excerpts will be self-updating excerpts displayed through selective transclusion, using the template {{Transclude lead excerpt}}.

Maintainers of specific portals are encouraged to sign up as project members here, noting the portals they maintain, so that those portals are skipped by the maintenance pass. Currently, we are interested in upgrading neglected and abandoned portals. There will be opportunity for maintained portals to opt-in later, or the portal maintainers can handle upgrading (the portals they maintain) personally at any time.

### Background

On April 8th, 2018, an RfC ("Request for comment") proposal was made to eliminate all portals and the portal namespace. On April 17th, the Portals WikiProject was rebooted to handle the revitalization of the portal system. On May 12th, the RfC was closed with the result to keep portals, by a margin of about 2 to 1 in favor of keeping portals.

Since the reboot, the Portals WikiProject has been busy building tools and components to upgrade portals.

So far, 84 editors have joined.

If you would like to keep abreast of what is happening with portals, see the newsletter archive.

If you have any questions about what is happening with portals or the Portals WikiProject, please post them on the WikiProject's talk page.

Thank you. 07:51, 30 May 2018 (UTC)

## Unruh effect predatory paper

An IP keeps adding a source in the Unruh effect article using the description Citing predatory open access journal, see [1]. If it is a predatory journal I don't think that we should accept it (it is not even an inline citation). Can anyone confirm? Here is the link to the paper [2]. --MaoGo (talk) 11:19, 30 May 2018 (UTC)

I don't know what a "predatory open access journal" is, but that paper is gibberish. I removed it from the article. Waleswatcher (talk) 15:19, 30 May 2018 (UTC)
see predatory open access journal. Headbomb {t · c · p · b} 15:31, 30 May 2018 (UTC)
OK, thanks. I reverted some other edits by that IP as well, all papers by the same set of authors. Waleswatcher (talk) 15:38, 30 May 2018 (UTC)
Articles from predatory journals should be considered with significant skepticism, as the articles in such journals are effectively self-published with little or no peer review. It can happen that a formerly non-predatory journal changes hands and becomes predatory, so not all articles are unconditionally unreliable. But IMO, like citing unaccepted/unpublished Arxiv papers, citing a paper from such a journal would need a justification for the exception. In this case, I agree that this general cite looks like a refspam article that is likely unreviewed. --Mark viking (talk) 17:37, 30 May 2018 (UTC)
Arxiv is at least moderated, so while it's not the best of sources for a lot of things, I'll take anything in arxiv over something from a predatory journal. Headbomb {t · c · p · b} 17:59, 30 May 2018 (UTC)

## Draft:Dror Fixler

Should this article be moved to mainspace? It is liable to be deleted for lack of edits in draftspace. Calliopejen1 (talk) 02:58, 4 June 2018 (UTC)

Well, thanks to your and my edits just now, it's immunized for another six months unless someone sends it to MFD. No comment on its relevance, just thought I'd mention it. Primefac (talk) 13:38, 4 June 2018 (UTC)

## Draft:Dislon

Input about this draft? It has a ton of references, but on first glance it appears that many of them may not actually be about dislons. I see that dislons are mentioned in the article quasiparticle. Calliopejen1 (talk) 08:03, 4 June 2018 (UTC)

This topic doesn't look notable to me. There is a single 2018 paper on the topic [3]. The mention in quasiparticle was added by the dislon draft author and looks like a bit of refspam. At best, WP:TOOSOON. --Mark viking (talk) 10:28, 4 June 2018 (UTC)

## Draft:Feodor Ivanovich Vilesov

Is this person notable? He won the USSR State Prize (which seems important) but I can find relatively little information about him (in English at least, and not seeing anything obvious and high-quality in Russian). Calliopejen1 (talk) 04:51, 6 June 2018 (UTC)

## No consensus:Fine electronic structure

As Fine electronic structure got no consensus. I think I will TNT it to make at least a nice stub. --MaoGo (talk) 13:33, 8 June 2018 (UTC)

## Various physics drafts

Over on WP:WPM we been working on identifying draft which come under our project and reviewing them at Wikipedia:WikiProject Mathematics/List of math draft pages. Part of this process involved finding draft which had mathematical of chemical equations in them. Quite a few of them come under your project and we have listed them at Wikipedia:List of draft pages on science and engineering. You may wish to examine these and see if any should be promoted to main space. --Salix alba (talk): 07:39, 12 June 2018 (UTC)

## Suggestion for a better name: Orbital angular momentum of free electrons

The article Orbital angular momentum of free electrons is weird to me, as it seems to imply that electrons as free particles may carry angular momentum apart from their spin. Do you have any idea what this phenomenon is about and to what name can we move it? MaoGo (talk) 15:03, 12 June 2018 (UTC)

OAM is a well-established concept associated with vortex beams; there is angular momentum associated with the topological vortex. See optical vortex, vortex laser beam, and orbital angular momentum of light for the optical analog. OAM for free electrons is more recent, but it has been established in the literature. I don't think there is a more common name for it. --Mark viking (talk) 16:42, 12 June 2018 (UTC)
There is nothing strange about it. It is just classical angular momentum. If the electron is moving on a line which does not pass thru the origin of the coordinate system, then it has angular momentum equal to the cross product of its position and its linear momentum. This is called "orbital" (i.e. depending on the trajectory or orbit of the particle) to distinguish it from the purely quantum mechanical "spin".
It turns out that it is also quantized in units of ${\displaystyle \hbar }$; always being an integer multiple of that unit. Whereas spin may be a half-integer multiple (but differences in spin are always full integer multiples). JRSpriggs (talk) 05:25, 13 June 2018 (UTC)
You are misunderstanding spin, if you think that all angular momentum is spin. JRSpriggs (talk) 05:51, 13 June 2018 (UTC)
In an atom, taking the location of the nucleus as the origin of the coordinates, the orbital angular momentum of an electron is described by the l and m quantum numbers. While the spin is described by the s quantum number. l is related to the eigenvalue of the total (magnitude) of the orbital angular momentum. m is related to the eigenvalue of the component of the orbital angular momentum parallel to an imposed magnetic field (or any other arbitrarily chosen direction). While these quantum numbers are usually used in the context of an atom, one could apply them relative to any coordinate system and use them to describe free electrons. JRSpriggs (talk) 08:57, 13 June 2018 (UTC)

If I understand this right, this article talks about a phenomenon that may only happen for a beam of electrons? I mean surely the article is not talking about an electron in a magnetic field. My problem is that angular momentum can be defined for free electrons in metals (see Landau diamagnetism) or for electrons in a cyclotron, or plasma or whatever. That's ok, but this phenomenon is about a specific case where we talk about a beam and I think a difference should be made more explicitly.MaoGo (talk) 09:24, 13 June 2018 (UTC)

Maybe we may change it to Orbital angular momentum of electron vortex beams MaoGo (talk) 09:31, 13 June 2018 (UTC)
We may also change its name to Electron vortex beam as it is already a redirect to it. MaoGo (talk) 12:18, 13 June 2018 (UTC)
I think "orbital angular momentum of electron vortex beams" is the least ambiguous title. XOR'easter (talk) 14:40, 13 June 2018 (UTC)
After taking my time to read the article and the sources, I think the article speaks about electron vortex beam, and not so much about the quantization. I think it should be called Electron vortex beam. MaoGo (talk) 08:42, 15 June 2018 (UTC)
I agree that Orbital angular momentum of electron vortex beams is the best title. orbital angular momentum is the major feature of this type of this type of electron beam. --Mark viking (talk) 17:55, 17 June 2018 (UTC)

I just made the bold move of making the move from OAM of free electrons to Orbital angular momentum of electron vortex beams. --MaoGo (talk) 11:59, 18 June 2018 (UTC)

## A-Class review for MAUD Committee needs attention

A few more editors are needed to complete the A-Class review for MAUD Committee; please stop by and help review the article! Thanks! AustralianRupert (talk) 07:26, 17 June 2018 (UTC)