User talk:YohanN7

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I just logged in for the first time in quite a while and saw that Chjoaygame has been topic banned. S/he has been a major reason I stopped or reduced my wikipedia editing in recent years, and in particular why I gave up on the wavefunction article. Rather than trying to clean up the mess there I'm considering wiping it all out by reverting back to before the bulk of Chjoaygame's edits, sometime around February 1st 2016, and then work on the lede and add that nice formula we discussed way back then on the talk page. However you did edit the article a few times in that period. So, before I do anything I wanted to check in if that's OK with you. If you'd prefer to take over yourself and do something like this that's perfectly fine with me. I'll wait a while to see if you reply. Thanks in advance! Waleswatcher (talk) 14:43, 24 April 2016 (UTC)

Great to see you back.
I'm sure your edits will be for the better. I had "planned" an edit that would move the entire section Wave functions and function spaces to the bottom of the article, as a preparation for possibly getting rid of it all together – or possibly it could stay, but the reader should not have to parse through it before getting to plane waves. I was also thinking about going through Chjoaygames edits, one by one, but a rollback to a semi-decent version as you suggests seems quicker.
Now, at least, we have room to breath. YohanN7 (talk) 07:22, 25 April 2016 (UTC)
Oh, in case the above is ambiguous. Go ahead! YohanN7 (talk) 07:24, 25 April 2016 (UTC)
Done for the moment, please have a look and see what you think. Waleswatcher (talk) 22:14, 29 April 2016 (UTC)
(I am positing here to prevent cluttering talk:wave function and to contact User:YohanN7 and user:Waleswatcher specifically and directly. If either of you prefer we can take it to that talk page). I don't want to interrupt edits to the wave function article, but was thinking of collapsing a lot of the article, especially where Dirac notation, general representations, units, and time dependence are concerned, to something like this. We can still keep the x/p representations and the relation between them for notability and concreteness, but the generalities must be collapsed and manipulations of the notation confined to the Dirac notation article, and all the repetition of specific cases for one/many, spin/spinless, 1d/3d etc. should be removed/reduced. Thanks for any feedback. MŜc2ħεИτlk 08:23, 30 April 2016 (UTC)
That's fine with me, please go ahead. Also, a minor point - I notice the format of the lede looks different today from yesterday.... somehow the equation and the text below it is getting pushed down by the figure showing the harmonic oscillator states, which (oddly) wasn't the case when I first made the edits. Maybe it's a browser issue? Waleswatcher (talk) 12:10, 30 April 2016 (UTC)
OK, I'll try rewriting now. The formula in the lead is wide and falls below the animation leaving a large chunk of whitespace. While I appreciate most people like the formula, it is very long and the labels may be awkward/distracting for some readers, so for now I'll remove it from the lead. The addition in my sandbox has the same thing explained in words. MŜc2ħεИτlk 13:21, 30 April 2016 (UTC)
Done for now, article is slimmer (22,473 kB have been lost), but more could be trimmed. May try more later tonight but in the mean time see what you think. MŜc2ħεИτlk 14:25, 30 April 2016 (UTC)
First off, I have not read anything in any detail yet.
I actually miss the full-blown Maschen formula. It need not be in the lead imo, but it could well go into the first spot in a section called definition. (A formula says more than a thousand words. A formula with words in it says even more.) YohanN7 (talk) 16:10, 2 May 2016 (UTC)
I felt the same, and (before reading your comment here!) added it back in a new section just after the lead. If you want to change the title of that section (or anything else), please go ahead. Waleswatcher (talk) 16:18, 2 May 2016 (UTC)
Ah, yes. I have had the page off my watch list for obvious reasons. Continue there? YohanN7 (talk) 16:46, 2 May 2016 (UTC)


Someone mentioned a comment you made at ANI. Here is the required ANI notice:

Information icon There is currently a discussion at Wikipedia:Administrators' noticeboard/Incidents regarding an issue with which you may have been involved. Thank you. Sławomir Biały (talk) 12:33, 2 July 2016 (UTC)

It took me a while to figure out exactly how I was involved and where. Since the matter seems to have calmed down, and I don't want to dive into the details of the matter, I'll simply retire with the observation that the (mis-) quote of mine offers good adviceFace-smile.svg this time as well. The ANI is full of crackpots seeking some sort of cyberspace careers there, and anyone brought there will defend in any way possible, whether legal or illegal. The best thing to do is probably to first alert "project pages" (the appropriate ones to which the article in question belongs). That way the fight is fought on the home turf. I do understand, however, why you brought this to ANI. If this particular crackpot somehow escalates the matter, I'll see if I can contribute with anything more specific and more to the point. YohanN7 (talk) 14:44, 4 July 2016 (UTC)

Math reference desk[edit]

Hi, I quickly skimmed your post to the math reference desk; I can't reply there .. not allowed, but thought I'd give a quick reply here directly. In short -- some of the qft functionals can be made mathematically rigorous, but if requires a math background far exceeding that available to a typical physics PhD (and teaching it would add on another 5 years to the students time-in-class). Yes, the WP articles on QFT are mostly abysmal, and it will take huge amounts of work to fix them, and show when/where more rigorous approaches are possible. The latest research, though is quite interesting: here's one from the grand-master Alain Connes himself: from which I quote: "This paper gives a complete selfcontained proof of our result announced in hep-th/9909126 showing that renormalization in quantum field theory is a special instance of a general mathematical procedure of extraction of finite values based on the Riemann-Hilbert problem. We shall first show that for any quantum field theory, the combinatorics of Feynman graphs gives rise to a Hopf algebra $\Hc$ which is commutative as an algebra....". Going back in time... one reason that supersymmetry initially got so exciting is that many variants were finite and required no renormaliztion. There was also a huge amount of interest getting a better grip on differential eqns in general, e.g. exactly solvable models, one poster-child of which was the Yang-Baxter equation .. which for example, describes the quantum deformations of the classical and affine Lie algebras (among other things). Another approach is the operator product expansion which avoids the problem of time-ordering of the quantum field operators by focusing solely on the operators for measureable quantities. So there's a huge amount of material here, its just so big its hard to grasp, and yes the WP articles in this area all need major improvements. (talk) 14:22, 19 September 2016 (UTC)

Re-reading your post -- maybe I can provide a much much simpler answer. First, there is no prescription for taking some diff eq describing some symplectic geometry (the diff eq of classical mechanics) and replacing the p's and q's by operators to get a valid first-quantized operator eqn. One can almost get there, the first steps are studied under the name of prequantization or geometric quantization, e.g. the Moyal bracket. One can perform a second quantization of lagrangians, though, and this is covered in almost any book on QFT. The mathematical methods thread their way through the theory of the Fredholm alternative, and lead into e.g. the trace-class operators and the study of topological vector spaces. The compact topological vector spaces are the same thing as universal enveloping algebras, thanks to the Gelfand–Naimark theorem (see also Tannaka-Krein duality). The quantum deformation of these leads to the quantum groups, for example, the Weyl algebra is the quantum deformation of the symplectic form --again anything with the word "symplectic" in it is really about classical mechanics. There are some marvelous books on classical mechanics that cover this: a very old but-still-modernish one is Abraham and Marsden from the 1970's. Another example are the clifford algebras which are deformations of the ordinary quadratic form aka metric tensor. Note that clifford algebras describe spin, which is why spin manifolds are studied. Lets see. Then the rotation group describes rotations in 3D space. Its covered by the spin group, which is covered by the string group which is covered by the 5-brane group in the Postnikov tower. So there is a huge effort to convert those squonky QFT theories, and to take any arbitrary lagrangian or hamiltonian, or poisson bracket and quantize it. Note that most possion brackets end up turning into Hopf algebras, which is why there's so much focus on that. The other key insight is that supersymmetry is the local, gauged version of the exterior algebra. Since the exterior algebra is central for solving differential equations, (by means of jet bundles, its not surprising that the locally gauged version of it is even more interesting.... (talk) 14:54, 19 September 2016 (UTC)