Talk:Noether's theorem

Wording of lead

Another editor made a Bold edit to the lead. I Reverted the edit. This section is created to Discuss the wording of the lead, in accordance with WP:BRD.

I believe that the lead should include the year in which Noether first proved the theorem. IAmAnEditor (talk) 23:49, 16 March 2018 (UTC)

I believe that the lead should also include the year of the first application of the theorem, which precedes Noether's. pgpgl (talk) 23:57, 16 March 2018 (UTC)

Unless there is a controversy about precedence or attribute of credit (of which is see no indication in the article), I would leave the proposed addition out of the lead. --John (User:Jwy/talk) 16:33, 17 March 2018 (UTC)

I have removed the mention of the Cosserat brothers' work from the lead for this reason (see also WP:PROPORTION and WP:LEAD). It might make sense to work it into the "Historical context" section, assuming sufficient support from secondary sources can be provided. --Duplode (talk) 01:20, 14 April 2022 (UTC)

I concur. XOR'easter (talk) 00:08, 1 August 2022 (UTC)

Explicit expression for the conserved quantity

The article lacks an explicó expression for the conserved quantity, like I on this video 181.118.72.29 (talk) 22:08, 31 October 2022 (UTC)

Please state and prove originally the theorem

The article should cleanly state the theorem as it was written by Noether (the original Noether's formulation of the theorem). And before starting to give several proofs it must state the original proof by Noether (the original proof). 86.38.215.220 (talk) 18:49, 14 January 2023 (UTC)

Unless the Noether theorem is wrong it would be great to have a version of this article at simple.wikipedia.org

I wanted to comprehend the theorem while being kind of unsophisticated. a simple wikipedia article could be created about Noether's theorem could be created right here: https://simple.wikipedia.org/w/index.php?title=Noether%27s_theorem&action=edit&redlink=1

I'm clueless, but it seems like it might be wrong based on what are described at wikipedia as time crystals, as well as even possibly turing machines, and any simple motional computing device — Preceding unsigned comment added by 2600:6C55:6400:7C81:7CAD:A826:9817:A54D (talk) 07:21, 25 July 2023 (UTC)

Noether's theorem is still true.

It can be applied in different ways; the physical laws underlying time crystals (at the most fundamental level) are the same as for all other phenomenona as far as we can tell, and those laws do not change over time (i.e. it does not matter when a time crystal 'starts', it would still behave the same), so energy is always conserved, even in a time crystal.

Noether's theorem can also be generalized and applied to a particle moving through a time crystal, and the changing nature of the time crystal would lead to the particle's energy not being conserved (but the remainder of the energy, when dividing by some constant energy depending on the time crystal, will be conserved by Noether's theorem https://physics.stackexchange.com/a/8528/317832). But accounting for the energy the crystal has as well, we should find that the total energy is conserved. Yodo9000 (talk) 14:16, 18 August 2023 (UTC)

Reference for the history of invariants

The section "3.3 SPACE-TIME AND INVARIANTS" in

Mehra, Jagdish; Symposium on the Development of the Physicist's Conception of Nature in the 20. Century, eds. (1987). "Einstein, Hilbert, and the Theory of Gravitation". The physicist's conception of nature: Symposium on the Development of the Physicist's Conception of Nature in the 20. Century held at the Internat. Centre for Theoret. Physics, Miramare, Trieste, Italy, 18 - 25 Sept. 1972 (Reprinted ed.). Dordrecht: Reidel. ISBN 978-90-277-2536-3.{{cite book}}: CS1 maint: numeric names: editors list (link)

provides a nice summary of invariants from Helmholtz through Noether.

This material could go as history of Noether's theorem, or in Invariant (physics) or even in general relativity. @ReyHahn any opinion? Johnjbarton (talk) 02:33, 13 November 2023 (UTC)

I think it is better suited for the invariant article. Is that the question?--ReyHahn (talk) 17:40, 13 November 2023 (UTC)

@ReyHahn yes thanks Johnjbarton (talk) 00:32, 14 November 2023 (UTC)

In the brief illustration image, does the author discuss such a lagrangian that only contains velocity or it also contains position variable ? If the latter, then why doesn’t dL/dx also contribute to the change ? If the answer is because of translation invariance, it would be good to state this, otherwise state that lagrangian is only a velocity function and not the position. Dextergio (talk) 15:02, 8 December 2023 (UTC)

I've added some explanation for why dL/dx doesn't contribute. It is a bit hand-wavy, but the goal of that section is to provide the intuition behind the reasoning, so I don't think the rigor would be too helpful there. L3erdnik (talk) 18:08, 10 December 2023 (UTC)