Wikipedia talk:WikiProject Physics/Archive January 2018

Atomic model

I added Dirac relativistic hydrogen atom to this template Template:Atomic models, please tell me if you disagree MaoGo (talk) 01:02, 22 December 2017 (UTC)

Update: I added the van der Waals equation as a model for gases and newtonian fluid for liquids. But now I have many issues I need to resolve: 1) Does every article that is linked in the template, need to have the Atomic models template? 2) What are atomic theories of liquid, gases or solids? Does that mean we should avoid pages like newtonian fluid as they are not an atomic model? (also it applies to gases). 3) Is it worth mentioning the free fall atomic model of Michał Gryziński or the nascent hydrogen? 4) Its liquid hydrogen a model?.

I propose to change liquids and gases to fluids and leave out obscure atomic models for the moment. Any feedback? MaoGo (talk) 18:19, 4 January 2018 (UTC)

Merging Fermi energy into Fermi gas

It is my first time doing a merging, but I think we need to discuss these two articles. Fermi gas is a more general concept but is better explained in the Fermi energy page. The latter has better equations and describes the most important aspects of the Fermi gas. I invite you to Talk:Fermi energy to discuss this merge. MaoGo (talk) 17:50, 4 January 2018 (UTC)

• Oppose because many things apart from Fermi gases have a Fermi energy, which is the more general concept. Xxanthippe (talk) 21:29, 4 January 2018 (UTC).

Xxanthippe, can you please copy that comment to Talk:Fermi energy#Merge with Fermi gas so that the whole discussion can be in one place? Thanks, --Steve (talk) 01:01, 5 January 2018 (UTC)

Done. Xxanthippe (talk) 01:47, 5 January 2018 (UTC).

proposing to NOT auto-insert an "SI dimension" line (using wikidata) in "Infobox physical quantity"

I feel like I'm in a never-ending (and futile!) war against infobox bloat. Here's the latest: Template talk:Infobox physical quantity#propose deleting - or at least not auto-inserting - "SI dimension". I am putting notice here because (1) it affects ~50 different physics articles, (2) I'm not good enough at template markup language (particularly involving wikidata) to actually make this change, if there's consensus for it. --Steve (talk) 14:59, 11 January 2018 (UTC)

IP at Talk:CGS system of units

An IP is having a conversation by themselves over there. I hate the CGS systems with a passion, and barely know anything about Gaussian units and the like. Maybe they have a point; maybe they're offering insight indistinguishable from the comment sections on a YouTube video about American politics. If someone from here could drop by and see what the fuss is about, that would be nice. Headbomb {t · c · p · b} 11:52, 15 December 2017 (UTC)

• The material is unsuitable for a talk page whose purpose is to improve its article, not to be a discussion the subject of the article. Xxanthippe (talk) 21:36, 15 December 2017 (UTC).

This IP was extremely helpful at Gaussian units last month—they caught numerous errors, they had lots of good ideas for improving the pedagogy, etc. etc. I suggest giving them benefit of the doubt. --Steve (talk) 01:09, 16 December 2017 (UTC)

• Since this "discussion" involves different IPs, I cannot comment on conversing "by themselves", but I perceive the material as suitable for the talk page of this article. I think the article lacks of strict treatment of dimensions/units, and the thoughts in this "conversation" may not all be worth transferring to the article, are wholesale unsourced(?), but are, imho, fully appropriate at the talk page. Taking into consideration that this topic has been dealt with by international commissions, the conversation is remarkably clear to me. Maybe, one should get explicit about the specific notions (4π, 2π, 1), addressed by the word "rationalization", maybe even a remark in the DAB. Purgy (talk) 07:58, 16 December 2017 (UTC)

The IPs (72.251.xxx.xxx) was a single editor who's now identified themselves Zophar (talk · contribs). I take no stance on the suitability of the discussion, since I understand very little of that topic, just like I barely understand anything in c = 1 relativity. I just wanted people who know something about cgs/gaussian units to figure it out, otherwise we could lose out on possible improvements, or knowledgeable IPs, or at the other end, have an IP that wrecks havoc on the article. People took a look, they seem happy with what transpired, so whatever else is to say about that should really be said on the talk page of the article. Headbomb {t · c · p · b} 01:23, 22 December 2017 (UTC)

@Headbomb: A belated thanks for bringing this to our attention. When I see such a long post on a talk page, with lots of proofs, my default assumption is that it's a crank, and if other people react the same way these posts could easily have been ignored. But Zophar was correct, and we have successfully encouraged them to make the changes themselves. RockMagnetist(talk) 18:24, 11 January 2018 (UTC)

Proton structure image

Please take a look here: talk:Proton#diagram of quarks in proton. Olaf (talk) 00:22, 15 January 2018 (UTC)

Statistical physics vs mechanics

There are two articles related to the field of statistical physics: Statistical mechanics and Statistical physics. The latter is ranked as a Start class of top priority, but I don't see why is so when Stastitical mechanics has a decent article. Is there a difference between the two fields? Should the articles be merged? MaoGo (talk) 12:00, 14 January 2018 (UTC)

I'd always assumed they were synonyms, or close enough. I agree that they should be merged, and more precisely (based on the current state of both articles) the merge should probably consist of simply deleting statistical physics and replacing it with a redirect to statistical mechanics. :-D --Steve (talk) 19:32, 14 January 2018 (UTC)

Whether these are synonyms seems to vary according to who you talk to. I've always regarded statistical physics as the broader subject and statistical mechanics as its subset. Statistical mechanics is typically about treating systems in thermal equilibrium, fluctuations about thermal equilibrium, and linear response theory. Statistical physics is about any kind of physics that treats a system in a probabilistic way. Examples of topics that fall into statistical physics, but not statistical mechanics, would include turbulence, dynamics of phase transitions, traffic flow, dynamics of small world networks, swarm dynamics, etc. Basically systems far out of equilibrium or for which there is no natural notion of equilibrium seem to fall outside of traditional statistical mechanics --Mark viking (talk) 20:57, 14 January 2018 (UTC).

If I had to make a difference between them, I'd say something like what Mark viking did, but I wouldn't trust an audience to pick up on the distinction without stating it outright, and I wouldn't expect any given author to be making that same distinction unless they said so themselves. XOR'easter (talk) 04:28, 15 January 2018 (UTC)

Even if the articles are different, I find it hard to see why we should keep both articles when Statistical physics remains undeveloped. MaoGo (talk) 12:55, 15 January 2018 (UTC)

Addition at Unruh effect

An IP posted an arxiv paper on the Unruh effect in the further reading section. I formatted the addition properly, but I'm not familiar enough with topic to judge if it's a useful addition or not. Feel free to take a look and decide. Headbomb {t · c · p · b} 13:40, 19 January 2018 (UTC)

First it lacks context. It should be norm to avoid arXiv papers that are too recent and do not have any phenomenal number of citations back, specially if they are provided anonymously (as in many cases we cannot get justifications back). The authors of the paper have treated Unruh effect in more recognized journals, maybe this kind of additions would be better if justified. I am certainly not an expert on the matter, so if someone disagrees be pleased to revert my following action, but I'm removing the addition. --MaoGo (talk) 14:33, 19 January 2018 (UTC)

I agree completely with MaoGo's deletion. Arxiv papers can become accepted as reliable sources through publication in respected media (in which case it is better to cite the publication) or through citation or coverage in reliable sources, but this 2018 submission does not yet have either. --Mark viking (talk) 18:49, 19 January 2018 (UTC)

It was my gut feeling too, but there are (rare) occasions where recent papers are warranted. Headbomb {t · c · p · b} 18:54, 19 January 2018 (UTC)

That is true. IIRC, the original arxiv submission about Amplituhedrons was one of those exceptions. --Mark viking (talk) 19:00, 19 January 2018 (UTC)

It is not infrequent that somebody publishes an arXiv paper and immediately cites it in some article in Wikipedia. As everybody here points out-the test is citations. Xxanthippe (talk) 21:37, 19 January 2018 (UTC).

Maybe we could add somewhere in the physics project guideline a line or two about referencing arXiv in this way. --MaoGo (talk) 01:32, 20 January 2018 (UTC)

The consideration applies to any paper, arXiv or not. Xxanthippe (talk) 21:22, 22 January 2018 (UTC). Xxanthippe (talk) 21:22, 22 January 2018 (UTC).

Wikipedia:Articles for deletion/MeKin2D

There's an AfD currently open for a kinematics simulation/modeling program. XOR'easter (talk) 01:46, 23 January 2018 (UTC)

When to update based on the 2017 CODATA values?

The CODATA 2017 special release has been highly anticipated, since it includes the constants that will be used to redefine the SI base units. But although CIPM has formally endorsed the the values to the CGPM and they have been widely publicized, the paper is still officially a preprint "in press" and not published. Also, the fundamental physical constants website still reflects the 2014 values (the last global adjustment) and not the 2017 special release which is limited to four constants.

Should the relevant articles be updated with the new values and uncertainties? If not, what are the preconditions?

Revisions to fundamental constants

Constant	2014 CODATA	2017 CODATA	(Proposed new SI)
Planck constant	6.626070040(81)×10−34 J⋅s	6.626070150(69)×10−34 J⋅s	6.62607015×10−34 J⋅s
Elementary charge	1.6021766208(98)×10−19 C	1.6021766341(83)×10−19 C	1.602176634×10−19 C
Boltzmann constant	1.38064852(79)×10−23 J⋅K−1	1.38064903(51)×10−23 J⋅K−1	1.380649×10−23 J⋅K−1
Avogadro constant	6.022140857(74)×1023 mol−1	6.022140758(62)×1023 mol−1	6.02214076×1023 mol−1

On a related imminent matter, when should the even larger edits to reflect the redefinitions be made? The proposal has been official since 2017-10-20. The formal CGPM vote (a "foregone conclusion"; there is no realistic chance it will not be approved) will be 2018-11-16. And the resolution specifies that it goes into effect on 2019-05-20. Any opinions on when the relevant edits should be made?

Thanks for help with this judgment call! 23.83.37.241 (talk) 11:31, 27 January 2018 (UTC)

I believe all four of these values are stored in {{physconst}}, so updating the values there will percolate through much of the existing usage. Of course, the template isn't used in every instance, but the rest can fairly easily be dealt with. As for "when", we should obviously wait until it's officially published. Primefac (talk) 15:59, 27 January 2018 (UTC)

I agree we have to wait, but we should prepare for this change and maybe be sure it can be implemented easily. --MaoGo (talk) 16:59, 27 January 2018 (UTC)

@Primefac: Good point! Ensuring that articles use {{physconst}} will enable the switch to be made quickly.

@MaoGo: Can you elaborate? Is "we have to wait" a response to my first question, or the larger redefinition question? And the first question goes on to ask, what are we waiting for? (I'd rather know "we're waiting until event E" than have to come back here every day and ask "are we there yet?", at least regarding easily anticipatable events.) I made a limited update to two of the articles which already mentioned draft values for redefinition, to incorporate the final proposals, but explaining the three separate values is awkward.

Thank you both! 23.83.37.241 (talk) 19:52, 27 January 2018 (UTC)

P.S. Should this discussion continue here, or be moved to Template talk:Physconst? That seems like a very appropriate place, and deserves a pointer to this discussion if it's to remain here. 23.83.37.241 (talk) 19:55, 27 January 2018 (UTC)

I know that there are more than a couple of articles that don't use the template, so having it here is a good idea; it's more heavily watched and we'll get better input. It's also very likely that anyone watching the template (enough to care about its maintenance) will also be a member of this project. Primefac (talk) 21:36, 27 January 2018 (UTC)

I agree it's "when published" for the values with uncertainty / and "when the CIPM accepts it" for exact values. Headbomb {t · c · p · b} 23:00, 27 January 2018 (UTC)

@Headbomb: "when the CIPM accepts it"... are you getting the CIPM (which accepted the values last October) confused with the CGPM (which will formally vote on the redefinition this November)? I agree that jumping the CGPM approval seems premature, but the part I'm uncertain about comes between the formal vote and the later date of effect. May we start revising articles in 2018? Do we have to add "to come into effect in 2019" caveats? I doubt most scientists will wait; I think the delay is mostly for the benefit of legal metrology, to give instrument makers and metrology labs time to revise their procedures without having to offend the CGPM delegates by anticipating their vote. 23.83.37.241 (talk) 23:36, 27 January 2018 (UTC)

My understanding is that the CIPM will vote on whether or not to accept the recommendation at the CGPM. But whatever the details are, the answer is 'when it's official'. Headbomb {t · c · p · b} 23:53, 27 January 2018 (UTC)

@Headbomb: Er, no. The CGPM (the "general conference") is the top-level deciding body, composed of national delegates from all the countries signatory to the Treaty of the Metre. It meets every few years, and delegates to the CIPM (the "international committee") which meets annually. (We just had the 106th CIPM meeting, but have not yet had the 26th CGPM.)

The CIPM proposes, and the CGPM votes on whether to accept, not the other way around. All major changes to SI have been ratified at CGPM meetings.

While negative votes are so rare these days that it seems like the CGPM is a figurehead which never refuses royal assent, that's illusory. Rather, with modern communications, issues are hashed out in advance and proposals are withdrawn if they are unlikely to pass at the physical meeting.

As for "when it's official", that's the ambiguity I'm asking about.

For the CODATA 2017 values, even after publication, they're less official than a full data release with all the covariances. Do we consider them to supersede the previous 2014 values, or not? Are they for general use, or do they only exist to enable the redefinition and the subsequent CODATA 2018 release? These are the questions I'm asking Wikiproject Physics.

For the anticipated redefinition, like much legislation, there's a date when it will be enacted, and then there's a later date on which it comes into force. Both of those dates are "official". Given that volunteer editing takes a long time, and the redefinition entails rewriting a lot of prose, Wikipedia will be wrong for a significant period of time around the transition no matter what start-of-editing date we choose.

There's a good argument to be made that a reader is less likely to be confused by stale information than by jumping the gun. But I also think that waiting until 2019 would be pedantically correct and practically useless.

The delay in coming into force is of little interest outside of metrology specialists (who aren't getting their information from WP anyway), but the publicity will peak around the time of the enactment, bringing lay and semi-technical readers to WP for information on the subject. Retaining the old information until 2019 would be more misleading than helpful.

The awkward thing is that this argument extends to editing before the enactment, so e.g. we can have a featured article ready for the day of. (In fact, I just booked the date.) That's where I get really uncertain, and I wonder what other people think. 23.83.37.241 (talk) 02:18, 28 January 2018 (UTC)

Just a note on your last point or two, there are some pages that are still using the 2010 CODATA results. As long as the numbers are sourced, out-of-date information isn't "wrong" it's just "out of date". This is why we include references. Besides, the lay person is only interested in the general numbers (electric charge is 1.6e-19, Avogadro is 6.022e23, etc), so the small variations (while important to update) are not super-vital.

Now, obviously, we're here to discuss when that date should be set, but I don't think we need to treat it with quite so much doom and gloom as I'm currently getting from your post. And I do appreciate the depth of information you gave at the start of your most recent post, since it gives us a direction to go towards. Primefac (talk) 04:52, 28 January 2018 (UTC)

In response to the IP, I was referring to the official publication of the document. In agreement with Primefac, this is not such a big deal. For those who wish to help, we/you can start recruiting some kind of team to verify that every template is and will be used correctly. --MaoGo (talk) 10:10, 29 January 2018 (UTC)

Recent edits at List of unsolved problems in physics

There's a bit of a difference of opinion unfolding at Talk:List of unsolved problems in physics. XOR'easter (talk) 02:13, 21 January 2018 (UTC)

Musashi miyamoto (talk · contribs) does not seem to understand that "why" type questions about physics are unanswerable. It is only meaningful to ask "what" type questions. JRSpriggs (talk) 12:44, 21 January 2018 (UTC)

Unsurprisingly, they're still going, well after they announced they were leaving. XOR'easter (talk) 14:56, 22 January 2018 (UTC)

We need to approach this problematic differently, the discussion still goes on. --MaoGo (talk) 14:55, 29 January 2018 (UTC)

They're calling Harold E. Puthoff and Bernard Haisch "notable physicists" and using a blog post about a magical space drive as a reference... I don't see this ending well. Oh, and they're giving more undue weight to a fringe theory than they were when I first commented there. So, we've gone backwards. XOR'easter (talk) 17:19, 29 January 2018 (UTC)

It does not stop. See Talk:List of unsolved problems in physics#Problem in astronomy, not physics and [1], after [2] and [3]. - DVdm (talk) 19:52, 30 January 2018 (UTC)

And it rolls on today. Apparently the fact that Einstein's most important papers were single-author works means that secondary sources are not necessary for an astrophysics claim published in 2010? XOR'easter (talk) 16:13, 31 January 2018 (UTC)