Wikipedia talk:WikiProject Physics/Archive January 2023

RM for Anti-de Sitter space with highly visible consequences
I have opened a move request at Talk:Anti-de_Sitter_space, which would require a spelling change across a large number of articles related to general relativity or string theory. In particular, AdS/CFT correspondence which is currently featured at WP:OTD on the Main Page, would be affected. –LaundryPizza03 ( d c̄ ) 10:38, 1 January 2023 (UTC)

Talk:Gauge covariant derivative
User:RogierBrussee argues that because he claims to have the qualification of a PhD (no less) he has enough expertise not to be required to support his edits with sources. Editors are invited to comment on this claim, and also on the edits themselves. Xxanthippe (talk) 02:53, 2 January 2023 (UTC).

My observation is that this significantly misrepresents the comments made by RogierBrussee. See the discussion at WP:RSN. I am not qualified to comment on the edits themselves as the subject matter is beyond my own expertise. Banks Irk (talk) 21:42, 2 January 2023 (UTC)

SPA warrior
Anyone interested in combating an edit warrior who seems to be new to WP and is using the name of one author (Alessandro Settimi) of an almost uncited 2013 paper, repeatedly inserting a reference to the paper into Magnetic monopole? See, , ,. —Quondum 20:48, 3 January 2023 (UTC)


 * Reverted as not having provided sources for the encyclopedic significance of the paper they promote at such length, warned for promotion. NebY (talk) 21:13, 3 January 2023 (UTC)


 * Appreciated. I'll keep a watch for a while.  Hopefully they will heed the warnings.  —Quondum 17:20, 4 January 2023 (UTC)

Redshift
I just noticed Redshift on the list of articles that became Featured a long time ago and need review. The intro paragraphs are rather choppy, which suggests that bits and pieces have been added without an overall plan; the citation formatting is not entirely uniform; it's old enough that it talks about WMAP but not Planck; it cites a couple ancient press releases, which ought to be evaluated to see if they need supplementing or replacing. XOR&#39;easter (talk) 16:41, 16 January 2023 (UTC)


 * There's also a fairly lengthy derivation that looks rather textbook-ish and could perhaps be condensed. (I think it's more encyclopedic to explain the assumptions, result, and significance of a calculation than to show its steps.) Thoughts? XOR&#39;easter (talk) 17:56, 17 January 2023 (UTC)
 * Condensed or even eliminated - it doesn't seem encyclopedic at all. PianoDan (talk) 20:04, 17 January 2023 (UTC)
 * I concur. Derivations are not generally appropriate in WP.  Explaining what something belongs here, but not how to show it, prove it, or otherwise understand its details.  Besides, they make it more unreadable.  —Quondum 22:34, 17 January 2023 (UTC)

Center of mass (relativistic) – delete?
Am I off my rocker, or is the article Center of mass (relativistic) complete bollocks? (I won't bite if you tell me the former holds.) It seems to me that any sensible definition of an isolated confined system in special relativity (i.e., Minkowski space with conservation of energy–momentum) must lead to a unique straight world-line that gives the centre of mass. If so, the article should be deleted. —Quondum 22:06, 9 January 2023 (UTC)


 * You are right. It is total crap. Another attempt by an anti-relativist to undermine the theory of relativity by misrepresentation. JRSpriggs (talk) 10:31, 10 January 2023 (UTC)


 * PRODed. It is easy enough to find a way of expressing the problem in a Lorentz-invariant way.  (Though I am a non-expert and not rigorous in my approach, I would welcome a debate with the author(s).)  There is also quite evidently WP:COI at play (self-citing own papers from WP) by essentially a WP:SPA.  —Quondum 02:46, 11 January 2023 (UTC)
 * Thanks. How did that weird article survive so long? --mfb (talk) 05:38, 11 January 2023 (UTC)


 * I find the article Velocity-addition formula to be similarly weird, starting with the title: it is not addition, but composition, and makes unstated or unclearly stated frame-specific assumptions. It reads like a collaborative project by first-year physics students who have not yet grokked four-velocity as a world-line tangent vector.  If it was notable, you'd think modern texts would all mention it.  —Quondum 13:18, 11 January 2023 (UTC)
 * I can attest to the basic velocity-addition formulas, under the name Lorentz velocity transformations as well as the informal description as addition of velocities, as Eqs. 2.23–24 in my own undergraduate textbook on special relativity, Thornton & Rex 4th ed. Regardless, the vast majority of the content should be abridged per WP:NOTTEXTBOOK. –LaundryPizza03 ( d c̄ ) 14:25, 11 January 2023 (UTC)
 * The article creates the impression that this is how the problem is typically or can reasonably be approached, despite its tendency to confuse Lorentz boosts with velocities. It seems to be talking about the composition of Lorentz boosts as parameterized by velocity, but non-collinear Lorentz boosts do not compose to another pure Lorentz boost, which cannot thus be parameterized by a velocity.  This should be dealt with in a section of Lorentz transformation, which it already is.  The article has seen a period when Ungar's weird gyrovector space idea was given prominence, since removed from this article.  To give an analogy, this no different from an "angle addition formula" on a sphere, where this "addition" is defined as the composition of a rotations around different axes through the centre of the sphere.  Anyone would recognize this as an incomplete and ridiculous way to work with the group of rotations in three dimensions in terms of one-dimensional "angle" parameters.  If a modern textbook talks about it, it should be only as an example of how not to think about it.  —Quondum 16:27, 11 January 2023 (UTC)
 * The addition of velocities terminology is commonplace; see, for example, the Feynman Lectures, where chapter 16 of volume 1 covers the addition of velocities in relativity . Mermin's introductory text on special relativity gives the relativistic velocity addition law in Eq. (4.2) and has a lengthy discussion of the topic. The article isn't in very good shape, but the problems don't include the title. XOR&#39;easter (talk) 18:26, 12 January 2023 (UTC)
 * I should withdraw my objection to established terminology used in pedagogical contexts. And I should avoid side-tracking this thread onto a examples of what I find weird.   —Quondum 18:59, 12 January 2023 (UTC)
 * No worries! The page does need attention, so it's good that you pointed it out here. XOR&#39;easter (talk) 14:22, 14 January 2023 (UTC)


 * That article creator had an article on their User page that I just moved to Draft space. You can find it at Draft:Instantaneous 3-spaces in Non-Inertial Reference Frames. Feel free to improve it or mark it as a hoax if you also think it is bogus. Liz Read! Talk! 02:59, 18 January 2023 (UTC)
 * , that editor's last edit was in April 2016. It appears to qualify for immediate deletion under WP:G13.  The text is somewhat surreal to read (what does it even say?), is completely unsuitable for an article and is likely unsalvageable, I can't even figure out what the title tries to capture and deleting it will not be a loss.  It is not a hoax, but it does seem to be the ramblings of someone who has failed to grasp important basics of relativistic physics.  —Quondum 13:32, 18 January 2023 (UTC)

FAs last reviewed from 2004 to 2007 of interest to this WikiProject
If you review an article on this list, please add commentary at the article talk page, with a section heading == URFA/2020 review== and also add either Notes or Noticed to WP:URFA/2020A, per the instructions at WP:URFA/2020. If comments are not entered on the article talk page, they may be swept up in archives here and lost. Sandy Georgia (Talk)  16:50, 19 January 2023 (UTC)
 * 1) Edward Teller
 * 2) Louis Slotin
 * 3) Redshift

Spin 3/2 and 5/2 fermions
Greetings! Does anyone know if spin 3/2 or 5/2 fermions have been empirically shown to exist, or are they purely theoretical? Other than the rotational symmetry, are they different in any qualitative way from spin 1/2 fermions? I'm asking because Spin 3/2 and Spin 5/2 redirect to Fermion, and they are not explained there. (Spin (physics) only has math which is meaningless to almost all readers.) -- Beland (talk) 19:44, 23 January 2023 (UTC)
 * Atomic nuclei with odd mass number are fermions (as composite particles are included in the definition), and as an example, lithium-7 has a spin of 3/2−. There are a number of nuclei with higher half-integer spins as well. Complex / Rational  19:58, 23 January 2023 (UTC)
 * There are baryons (baryons are fermions) with these larger half-integer spins. See Delta baryons and Sigma baryons.  Again, these are in some sense a composite of "elementary" fermions.  —Quondum 21:19, 23 January 2023 (UTC)

"speed of light in vacuum" vs. "speed of light in a vacuum"
If anyone cares which version WP "should" use, you may wish to comment at Talk:Metre. —Quondum 20:17, 18 January 2023 (UTC)


 * Some stats for interest only, not apropos any specific article: preference between these versions of the phrase shows a distinct change with scholarliness, from roughly even in general use to strongly one-sided in scholarly/academic use, even though both forms are common enough to be regarded as "correct English". Here are some sample statistics:
 * ngram: roughly even, a small edge to the first around the time of the introduction of the SI
 * Google first bunch counting first ~20 gives roughly 1:1 ratio
 * GScholar first 50 counting first ~50 listed gives roughly 8:1 ratio
 * GScholar: ~60k vs. ~20k
 * nist.gov 1240 vs. 384
 * bipm.org: 69 vs. 2
 * —Quondum 01:06, 30 January 2023 (UTC)
 * Is there a difference between US English and UK English? If there is is probably still does not help us to decide? --Bduke (talk) 05:51, 30 January 2023 (UTC)
 * My impression is that usage is not highly dependent on which region one considers. In any event, I am not looking to argue any issue.  —Quondum 15:22, 30 January 2023 (UTC)

FAR for uranium
I have nominated Uranium for a featured article review here. Please join the discussion on whether this article meets the featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" in regards to the article's featured status. The instructions for the review process are here. Hog Farm Talk 18:35, 30 January 2023 (UTC)