Talk:Superconductivity

the superconducting state breaks no symmetry

Clearly, the simple s-wave superconducting state does not break the local gauge invariance (it is still there in the superconducting phase) or any other symmetry for that matter. Therefore, I find the sentence "The existence of these "universal" properties is rooted in the nature of the broken symmetry of the superconductor and the emergence of off-diagonal long range order." a bit confusing.

IISc paper

Has anyone read the paper for which we keep reverting the inappropriate additions? I don't know where to find it, and the comments being made in support of it: Their material will have superconductivity suggest to me this is not only not peer reviewed, but speculative. Tarl N. (discuss) 19:27, 9 June 2019 (UTC)

A new IP editor, 2405:205:2294:E57E:44A9:1D12:8A38:60A0, has inserted the same content, in the same format, as Lokeshguta149 is pushing. It is his only edit. 2405:205:2294:E57E:44A9:1D12:8A38:60A0: are you the same person as Lokeshguta149? A single editor using multiple accounts pretending to be different people to deceive and push content is called WP:SOCKPUPPETRY, and can get you banned. Any more of this and I will report you to an administrator. --Chetvorno^TALK 19:57, 9 June 2019 (UTC)

Well, the edit summary is identical too, and the IP is located in New Dehli, so by WP:SPI standards, we can say it quacks like a duck. However, under WP:AGF, I'd assume the editor simply forgot to log in. Tarl N. (discuss) 03:44, 10 June 2019 (UTC)

For what it's worth, looking up the author names specified at IISc preprints I see this paper: Recent advances in the preparation of nanocrystal solids, the only paper jointly authored by the indicated researchers. It's from 2015, and from the description, has nothing relating to the spam/promo we're seeing here. It's behind a paywall, and I don't have the energy to fetch it through my university, since it is unlikely to have any bearing on what has been posted. Tarl N. (discuss) 04:01, 10 June 2019 (UTC)

I've requested page protection, since this spammer is now using changing IPs on a wireless network. Tarl N. (discuss) 16:12, 10 June 2019 (UTC)

The article in question is at arXiv:1807.08572. See also arXiv:1906.00708 and arXiv:1808.02929. Brienanni (talk) 07:07, 10 June 2019 (UTC)

Thanks, in particular for that last paper referenced. Let's wait until peer review gets through these. Tarl N. (discuss) 16:14, 10 June 2019 (UTC)

@Tarl N. and Chetvorno: Could editors here keep an eye on Room-temperature superconductor. The Indian Institute of Science stuff is still there, maybe it's appropriate for that article but I don't think this patent stuff was [1] and it lasted quite a while. And yes I appreciate this is technically OT here since it isn't about improving this article but while I raised concerns at WP:FTN a couple of months back (hence the edits), I wonder if this is the better place to get the attention of editors experienced in the field. Nil Einne (talk) 08:22, 30 July 2019 (UTC)

Rutger's Formula

Hello,

My draft for a stub on Rutger's Formula was declined. According to a frequent editor, this was mostly due to "lack of context". I think it might work instead as a section of this article.

Is this a possibility?

Miguelmurca (talk) 10:21, 14 October 2019 (UTC)

Google seems to find more refs (which seems to be the main reason the draft was declined) - but the content seems to be mostly about the derivation of the formula - which seems too detailed for this article. Can I suggest adding more refs to the draft, extending its introduction, and putting a very brief mention to Rutger's formula where/if this article talks about a step change in specific heat. - Rod57 (talk) 18:39, 4 January 2020 (UTC)

@Miguelmurca: I would suggest that the article needs some english language verbiage; notably, what does it mean? "discontinuity in the specific heat". I've had undergrad physics, I think I understand it, but this is wikipedia, not a textbook. Explain in words what happens to specific heat at Tc (a graph would be useful), and why we care about it across that boundary. Also, some history. Who was Rutger, and why is the formula named for him? All of this, obviously, with citations. I will also mention that you are likely to run into some paranoia about naming, so make sure it's clear with secondary sources that the name is widely accepted. Regards, Tarl N. (discuss) 21:42, 4 January 2020 (UTC)

Addendum, it seems likely that the draft is misnamed - "Rutgers Formula" looks to not have an apostrophe. Which suggests it's named after the university, rather than a person. Tarl N. (discuss) 21:48, 4 January 2020 (UTC)

Should we mention Migdal-Eliashberg theory or Eliashberg theory

Should we mention Migdal-Eliashberg theory : Accuracy of Migdal-Eliashberg theory and Coulomb pseudopotential 2011? Starts:

"The Migdal-Eliashberg (ME) theory provides a very successful method for describing conventional superconductors, where the pairing is driven by a phonon-induced attraction. This theory is based on Migdal’s theorem, stating that vertex corrections can be neglected if the phonon energy scale (𝜔0) is much smaller than the electronic energy scale (𝐷). This should be true even if the dimensionless effective electron-phonon coupling 𝜆 is much larger than unity, as long as (𝜔0/𝐷)𝜆 ≪ 1. Thus vertex corrections are neglected in ME theory, which is a huge simplification."

Breakdown of the Migdal approximation at Lifshitz transitions with giant zero-point motion in the H3S superconductor talks of the Migdal approximation to standard Eliashberg theory. - not sure how to summarise it ? Is it just a way to simplify the calculations within BCS ? or does it apply in any way to any of the unconventional superconductors ? If it doesn't belong in this article, where should it go ? - Rod57 (talk) 18:00, 4 January 2020 (UTC)

Eliashberg Theory 2013 looks like a review of Eliashberg theory (1961) and mentions various approximations (including Migdal 1958). Perhaps Eliashberg theory is a theory for SC where electron-phonon interaction can be strong (whereas BCS is better only when electron-phonon interaction is weak) ? - Rod57 (talk) 18:29, 4 January 2020 (UTC)

Proposed series for superconductivity (Sidebar or Footer open for discussion)

Hi all, I created Template:Superconductivity which mostly contains all the links in the see also section of this article arranged in categories. I am no longer fully convinced it is needed, but thought it was a great idea when I started. (There are a lot of a articles here that relate to superconductivity and you have to follow a lot of links sometimes to find specific information) I would like to know what others think. If you like the idea, feel free to edit Template:Superconductivity to help make it more useful. Thanks! Footlessmouse (talk) 05:51, 15 August 2020 (UTC)

Hi Footlessmouse. My question is: where would you use it, where would you put it (in those articles), and how different is this from "See also". Sometimes, these templates become too big (you're already there), lose focus, and don't look very nice in articles (especially when people put them in the lead), so I have mixed feelings. But that's just me... Ponor (talk) 23:19, 15 August 2020 (UTC)

Hi Ponor, thanks for the reply. I agree that it already has too much in it. It would be better as a footer, I believe. The primary advantages of using the template, in my opinion, is 1) to reduce the size of the see also sections across the articles to only mention those articles that are most relevant to the current article (links to articles which a significant portion of new users are likely to follow after reading the current article). 2) To allow the template to be standardized across all the articles, so that it is easier for new users to surf around the topic. 3) To categorize the articles that would otherwise be in the see also sections, so that it is easier to find a specific topic of interest. The main disadvantages are maintenance and brevity. Like I said, I'm not convinced either way, but wanted to see what others think. Footlessmouse (talk) 00:02, 17 August 2020 (UTC)

I checked few articles with similar templates. Quantum Mechanics article has an enormous one, with collapsible sections. I have to admit I don't think I ever used any of these. I wonder if "See also" sections are that important. It's the wikilinks that we like to follow, because they (should) put things in context, not just list them. Templates may be good for our bookkeeping, but articles are best linked by wikilinks... imho. Ponor (talk) 00:56, 17 August 2020 (UTC)

If by wikilinks you mean links in the text that link to a subject when it is mentioned, then agreed. I believe that is, by far, the most useful means of navigation. I still use templates, though, but not too often. It's usally for the 3rd reason above, when I am surfing through random phenomena, experiments, or people tangentially related to a given topic. It also doesn't seem like this is too big of a deal and not too many are interested in it. If anyone else likes the idea, please let me know, otherwise we'll just leave everything as is for now. Thanks! Footlessmouse (talk) 01:23, 17 August 2020 (UTC)

FYI: Found this recent discussion, some interesting arguments against using the sidebars (e.g. They're missing from mobile pages, yet no complaints) @Footlessmouse:

https://en.m.wikipedia.org/wiki/Wikipedia_talk:Manual_of_Style/Lead_section#Sidebars_(navboxes)_should_NOT_be_used Ponor (talk) 11:57, 19 August 2020 (UTC)

This is interesting and it does make several good points. I can agree that the sidebars should be kept out of the lede and a picture, if available, should be the first thing in the upper-right-corner of the page. I will keep this in mind in the future. Footlessmouse (talk) 21:39, 19 August 2020 (UTC)

Don't Cooperpairs need energy to form / Maybe someone can explain

About this part of the article, right at the start: "... below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source ..." Well first of all the first source is down.

Then: As I understand it, the band gap is a dynamic balance. So there are continuously forming Cooper pairs and breaking apart. Every time a Cooper pair forms, it takes around 1 meV. That ain't much, naturally, but it is something... so wouldn't that energy change its form, ie not be part of the equation anymore, so that an electric current through a loop of superconducting wire should not persist indefinitely, but continuously "lose" an insanely small amount of energy, until nothing is left, unless you could create a superconductor at 0 Kelvin, which is proven to be impossible to reach?

I feel like zero resistance would somewhat break the laws of nature as it is the case with zero Kelvin. Maybe someone can clarify. --Leo Navis (talk) 19:39, 29 March 2022 (UTC)