Talk:Josephson effect

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Practical uses and follow-up

In earlier versions, the article contained more links and comments about practical issues. Why they vanished is unclear to me ... Filou 22:11, 4 September 2007 (UTC)

'The Josephson effect is the phenomenon of current flow across two weakly...' shouldn't this be more specific current of cooper pairs, so not quasi particles?--129.125.6.1 (talk) 10:32, 4 December 2008 (UTC)

Practical uses and Nobel Prize worthiness

There isn't a single word about practical uses or its generic significance to further advancing physics. I mean Nobel prizes are awarded for achievements beneficial to the mankind, abstract beauty is not enough.

Maybe his psychic quantum theory powers affected the judges enough to nominate him?

I'd have to agree; the article should mention why this was considered Nobel-worthy. --Starwed 10:42, 5 May 2007 (UTC)

Uses ?

There is nothing about what all this means! I mean, it explains the technical parts, gives the proof, shows the equation- all of which is well and good, but I came beause I heard it was being used in ultra-fast chip prototypes and other interesting devices, and the page gives me nada. -- maru

I think the writer could only benefit from understanding the physical principles behind the Josephson effect, before engaging in the trivia of applications, which sadly risk becoming nothing but a mindless tabulation of data, without the deeper understanding, which lately seems to have become a dirty word. Certainly the applications are humanly and economically very important, but please spare us from having the applications promoted and discussed by fast Eddy, and other busybodies who are too eager to talk about some reality using a few memorized buzzwords, but are incapable of doing anything useful with that reality.

I have no real problem with the principles and the explanations; however, in the end all research should come back to pratical applications- science is a tool, not an art. And I have no idea what most of your comment is talk about. --maru (talk) Contribs 18:16, 21 January 2006 (UTC)

I got into this for reasons that can be seen from the Anderson-Rowell section of this talk page. Apart from correcting a misspelling of my name I'll leave the article untouched, but comment that the statement of what I discovered seems to me unhelpful, and unless one is going to go into great detail talking about phases etc. (which would merit a section its own) the best thing would simply be to indicate that 1962 was the date when the predictions were made. I'd also like to add that theoreticians would strongly dispute the suggestion that research in physics is only of interest in terms of practical applications. That would among other things rule out astronomy, whose practical relevance stopped as soon as the positions of the sun and moon were figured out. That isn't of course to belittle the importance of discussing the practical applications and including them in the article. --Brian Josephson (talk) 16:31, 16 May 2012 (UTC)

There is another entry, Josephson Junction , which describes a bit the applications. Maybe the content of these two articles coulb be merged in the future?

That seems like a good idea to me; the effect seems to be more embracing than the junction, so I would merge in Junction to Effect. --maru (talk) Contribs 18:16, 21 January 2006 (UTC)

entries merged

The content of the page Josephson junction has been merged into the page describing the Josephson effect, and a few words about applications have been added. All this can still be improved, feel free to do it. Filou 22:21, 23 January 2006 (UTC)

Correction

Added a correction: the Josephson effect does not define the SI volt, it is presently used as a representation for the volt (there is a relative uncertainty of 4 x 10^-7 of the voltage generated by the Josephson effect to the SI volt.) Dalle 19:55, 15 March 2006 (UTC)

• Looks to me like it is: Volt Confuted 01:58, 19 January 2007 (UTC)

Temperature unit

I changed Kelvin to kelvin, to follow proper SI practice in English.

References

Hi, I just replaced one broken reference with full quotation and link to the original paper. Actually great part of the article on Jospehson effect seems to follow the Josephson's 1974 review on his own discovery done in 1962. Danko Georgiev MD 09:49, 31 May 2006 (UTC)

I-V characteristic

I am working with Josephson junction every day, but I never saw such a strange I-V characteristic. Can this be substituted to something standard like tunnel JJ IVC or RSJ IVC?

Historical question

The Biography for Josephson says that he discovered the Josephson effect. The introduction for the Josephson effect (this article) says that he predicted it. Which is correct? This discrepancy should be addressed.

This bothered me too, but I imagine it's sloppy language; predicting an effect can be thought of discovering it's possibility in a theory. But even if that's what was meant, it certainly gives the wrong impression. --Starwed 10:40, 5 May 2007 (UTC)

Consistency in Equations

Is the proper constant in the equations $\displaystyle {\frac {\hbar }{2e}}$ or $\displaystyle {\frac {h}{2e}}$? $h$ and $\hbar$ differ by a factor of $2\pi$; this article uses them interchangably. Confuted 01:59, 19 January 2007 (UTC)

In its current state, the article uses $h$ only when giving the frequency. This is correct. The angular frequency (e.g. rad/s) is ${\frac {2e}{\hbar }}\cdot U_{DC}$, but the frequency (e.g. 1/s) is ${\frac {2e}{h}}\cdot U_{DC}$. -Beastinwith (talk) 17:22, 5 August 2008 (UTC)

I wonder if you want to leave the reader with that confusion or at least uncertainty on the mixed use of $h$ and $\hbar$ in this article? For the sake of clarity, please use one or the other, but not both.

Reddwarf2956 (talk) 00:32, 23 August 2009 (UTC)

Clarification

My impression from reading other sources is that a current must be induced in the case of the DC Josephson effect. The special thing is that the current then flows across the barrier without a voltage drop. If this is accurate I think it should be mentioned in the description of the DC Josephson effect. -Beastinwith (talk) 03:42, 5 August 2008 (UTC)

Physical Intuition

This entry contains little in the way of physical interpretations of the Josephson effects. If anybody has some physical intuition beyond the listed equations I think that including it would improve the article. -Beastinwith (talk) 03:42, 5 August 2008 (UTC)

the effect also occurs in superfluids. http://en.wikipedia.org/wiki/Quantum_gyroscope http://www.innovations-report.com/html/reports/physics_astronomy/report-39604.html. just-emery (talk) 12:56, 8 May 2009 (UTC)

clearly the thing that ties all these things together and that forms the basis of superconductivity and I presume superfluidity as well is 'cooper pairs' (and/or 'lone pairs'). readers that want to dig deeper into this phenomenon should probably be directed there. just-emery (talk) 13:28, 8 May 2009 (UTC)

According to the article Superfluid:

"Superfluid acts as if it were a mixture of a normal component, with all the properties associated with normal fluid, and a superfluid component."

I assume that the same is true for superconductors. If so then the nonsuperconducting component would be responsible for the voltage drop while the superconducting component would be responsible for the ac current. just-emery (talk) 23:52, 3 July 2009 (UTC)

ac josephson current/energy loss

the ac current must radiate energy so how is it replenished? just-emery (talk) 12:35, 8 May 2009 (UTC)

From the source that supplies the dc voltage. --Brian Josephson (talk) 16:36, 16 May 2012 (UTC)

t

Is t in the equations the time or the thickness. At this point I think it is the time, but before reading below I interpreted it as the thickness of the gap. Would someone please state which it is? David R. Ingham (talk) 22:02, 20 January 2012 (UTC)

t is time Tls60 (talk) 22:42, 20 January 2012 (UTC)

Anderson-Rowell reference

Following comment by Anderson, who may have looked in the reference list at the end and found that his paper with Rowell announcing the first experimental observation of the effect was not included, I've made the in-text reference a proper reference (is it only subjects like cold fusion that the w'pedia vigilantes give their undivided attention to?). I merely transferred the details that were there, and maybe someone with the time to spare can (a) check the reference is correct (b) include the title of the paper (c) include a suitable link, doi or whatever.--Brian Josephson (talk) 11:02, 16 May 2012 (UTC)

Update: ignore the above request: I found I had the title ready to hand, and it is all fixed now! --Brian Josephson --Brian Josephson (talk) 16:10, 16 May 2012 (UTC)

I've learned that it was Anderson himself who put in the key reference. At his advanced age he can perhaps be excused for not doing it in the officially authorised way! --Brian Josephson (talk) 08:08, 17 May 2012 (UTC)

magnetic field sensitivity

The article lists 3 main effects (DC/AC/inverse AC), but the magnetic field sensitivity is equally important and should be included in the list, with a suitable accompanying graphic. --Brian Josephson (talk) 08:07, 17 May 2012 (UTC)

Request to Brian Josephson

Could Brian Josephson make his article containing the prediction of the effect openly/freely available (as a link) to all readers of the Josephson effect article in Wikipedia?--86.120.44.145 (talk) 17:57, 20 May 2012 (UTC)

I.M. Yurin's Theory

I'm removing the paragraph that links the article by "I.M. Yurin". The article in question, while it is in a peer-reviewed journal, has not been cited elsewhere, and does not seem to be notable enough to warrant inclusion. The author does not appear to be associated with a notable university or research institution, and I suspect that the article author himself is the one posting this information. If the editor chooses to restore the link without commenting on this page, I will refer the matter for dispute resolution, as he has already engaged in the same behavior on the BCS theory page. PianoDan (talk) 20:13, 20 November 2012 (UTC)

merge/add Josephson energy into Josephson effect

I'm proposing a merge from the Josephson energy article, which seems to cover a fair amount of the same ground as this one, with additional math. If the two articles should be separate, the Josephson energy article needs to be cleaned up and have references added. I'm not familiar enough with the topic to tell if there should be separate articles or not, but it looks like this is the more comprehensive article. -- phoebe / (talk to me) 04:36, 2 January 2013 (UTC)

• Yes, at this point the merge would be beneficial for both articles (and yes, I am familiar with the topic). In principle, I can imagine a separate article on Josephson energy, but this requires a fair amount of work to create it. What is it there now is best to be merged.--Ymblanter (talk) 06:53, 2 January 2013 (UTC)

I think that merging is a good idea.