Talk:Instanton

Removal of issues banner
Given the importance of the topic, not being the highest, it is sufficiently technical in its description, compared with other articles such as Quantum Chromodynamics. It has a variety of sources, and as such, I have seen it fit to remove a nearly decade-old banner at the top. Any objections will be heard; this decision may be reverted for any reason if deemed fit. — Preceding unsigned comment added by SpiralSource (talk • contribs) 19:46, 3 February 2022 (UTC)

Comprehensibility
Very nice, but the article doesn't actually say what an instanton is. Anyone with enough knowledge of theoretical physics want to take a crack at putting some text in this article? Erik Carson

Followup: Ask and ye shall receive. Erik Carson 19:57, 2004 Mar 30 (UTC)


 * I am a mathematician trying to understand what this article means mathematically, but am limited by the deluge of physics jargon starting from the very beginning of this article. Could at least the introduction be rewritten to be understandable to someone without graduate-level physics knowledge? - Gauge 04:40, 21 August 2005 (UTC)


 * I've just rewritten the article so that it explains the more general meaning of the term "instanton". The relation to Yang-Mills gauge theory in Minkowski space should be clarified in a subsection.  I apologize for leaving the edit in an incomplete state; it will take some time to get everything right.


 * I'm not a physicist, but I consider myself familiar with physics (I've taken plenty of classes on the topic) and I find this article almost unreadable. I had to read several other articles - most of which turned out to be unrelated - and I still found this article tedious and vague.  I appreciate that some people have worked on this problem but it is far from being completely fixed.  I'm not in a position to be able to translate this article, so I am asking here that someone familiar with this topic will please take the time to rework this article, making it readable for those of us who don't work at CERN. Thanks! Spiral5800 (talk) 06:24, 21 July 2012 (UTC)


 * Exactly! I consider myself well versed in physics, but this page makes my eyes glaze over as I read it. Completely incomprehensible. As an additional note: I believe a top priority for this article MUST be to discuss how instantons are the same/different than virtual particles (I'm new to this, so I don't know how to link the article but feel free to reference it if clarification is needed). Even though I know what virtual particles are, this article is so unintelligible that I have no idea after reading it if they are the same thing or not. I'm guessing not since both articles exist, but that means that someone needs to clarify how they're different. Unfortunately, I'm clearly not qualified to be the one to do that. Science Is My Life (talk) 06:07, 31 October 2017 (UTC)

U(1) doesn't have instantons. $$\pi_3(U(1))=0$$. No Abelian gauge theory has instantons. Phys 20:17, 20 October 2005 (UTC)


 * U(1) gauge theories in two dimensions do have instantons. Spatial infinity here is a circle, and $$\pi_1(U(1))=Z$$.  This is the case the author was discussing.

The section "Quantum Theories" starts out with "In such theories" but there's nothing to specify exactly which theories are being talked about. 68.134.202.201 (talk) 01:27, 30 November 2015 (UTC)NormDrez


 * how is this article useful to anyone but someone with PHD in QED etc. Juror1 (talk) 05:27, 8 August 2017 (UTC)

Put some "m"
Just put the "m" relating to the mass of the particle where needed in the part about Instanton in Quantum Mechanics

Typo
The WKB expression for the probability for the particle to tunnel should be real. The i should be replaced with a 2.

http://upload.wikimedia.org/math/5/c/7/5c719dcaa6e7112fb76f501b5f57a598.png —The preceding unsigned comment was added by 71.136.90.228 (talk) 13:03, 7 December 2006 (UTC).

Noncommutative and SUSY instantons?
Maybe someone could also add at least a note that instantons also exist on noncommutative spacetimes, as well as for supersymmetric gauge theories. And mentioning the ADHM construction would also be good. In particular, its interesting that in the noncommutative case there CAN exist U(1) instantons.

Factor of two mistake corrected
I deleted the factor of two in front of the cosine in the proof of the BPS-bound.

Matrix1329 11:42, 19 April 2007 (UTC)

Nonmathematical explanation?
Is it possible for the introduction to explain the concept in a way that relies on neither mathematics nor physics PhD-level knowledge? This article is as good as gibberish to anyone without that knowledge. Like, it could all be a giant joke, and we wouldn't know. If it's not explainable in terms nonphysicists will understand, it simply isn't, but in that case is it really notable for Wikipedia's purposes? 134.10.18.182 (talk) 08:25, 9 May 2010 (UTC)
 * I've noticed this about many Wikipedia articles, particularly physics and mathematics articles. An Encyclopedia is supposed to be written in such a way that someone with basically a High School education can understand it. Or at least link to articles designed with such people in mind. Blooddraken (talk) 10:24, 7 May 2011 (UTC)

Not quite. — Preceding unsigned comment added by 81.213.55.37 (talk) 13:06, 30 May 2011 (UTC)

Unfortunately it's the habit of people who reach a graduate level of education to act elitist about their fields. Physicists, mathematicians, doctors, lawyers, sociologists, you name them, they will try to pretend a person who hasn't spent at least a decade studying their field has no chance of understanding what they're going on about. Here's a start to a layman's definition: http://www.phys.virginia.edu/research/graduateposters/jwm8n_99/whatis.gif — Preceding unsigned comment added by 110.38.203.219 (talk) 13:59, 20 April 2012 (UTC)

No, my friend, it's not elitism - it's just Wikipdedia. That is, an article written by someone who thinks he knows the subject. — Preceding unsigned comment added by 165.120.252.133 (talk) 12:18, 22 December 2019 (UTC)

Quantum mechanics
I'm confused by the author mentioning Minkowski in the quantum mechanics setting. Everything looks like nonrelativistic QM for me. I've nobody objects, I will try to rewrite the text, getting rid of Minkovsky completely and taking about real and imaginary time. Fabian Hassler (talk) 07:44, 4 August 2010 (UTC)


 * I think that the point is that instantons may be considered both in the more physically motivated Minkowskian space-time and in mathematically more familiar Euclidean space-time (these generalize to Lorentzian and Riemannian manifolds, respectively).


 * A bit of general advice: when making local edits, please, make sure that your sign conventions, etc are consistent with the rest of the article: agreeing with a particular source that you are familiar with is unsufficient, unless you are willing to rewrite everything according to its conventions. In other words, either tread lightly or accept the full burden of correctness for the article as a whole. Good luck! Arcfrk (talk) 07:22, 5 August 2010 (UTC)

What is the purpose of note 1?
Could anybody explain why Note 1 is included? In field theory equations of motion tend not to refer to translations, rotations or oscillations. GaramondQ (talk) 14:52, 22 April 2021 (UTC)

Speculation in the summary
Both in the initial summary of the topic and in a later section (Further studies) a few lines have been recently added:

"On 1 October 2023, astronomers proposed a new, more comprehensive, view of the cosmos, and which includes all objects in the universe, and suggested that the universe may have begun with instantons, and may be a black hole."

This being current ongoing research, I don't think it should appear in the summary of the article, and possibly not at all. It seems to me advertisement of someone's research rather than informative material. MatthiasCarosi (talk) 12:55, 21 October 2023 (UTC)