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Merge discussion
The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.A summary of the conclusions reached follows.
Oppose. This merge discussion appears dead anyway but I am strongly against it. Dimensionless constants are an important sub-topic of physical constants. This is an over-merge that would quash discussion of an important issue as the physical constant article is already too long to merge this as a proper section.
Jason Quinn (
talk)
07:14, 27 June 2016 (UTC)reply
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
Correction for molar mass constant
The molar mass constant is listed as 0.99999999965(30) kg⋅mol−1 but I believe the correct value should be 0.99999999965(30)×10−3 kg⋅mol−1.
I'm new here, so I couldn't figure out how to make the edit myself.
As the tables of listed constants grows, this article has taken on the nature of a list-class article. It seems appropriate to move these tables to
List of physical constants (currently a redirect), leaving behind a short section with a hatnote linking to it, and a short table of frequently used physical constants. Opinions? —
Quondum23:01, 21 June 2019 (UTC)reply
Done
SI time vs Uzan?
The SI system uses ΔνCs for its time definition. The second on "Number of fundamental constants" is based on Uzan's long paper, but it does not call out a time or frequency definition. I think we should have some comment about how these two compare.
Johnjbarton (
talk)
17:26, 10 January 2024 (UTC)reply
I'm afraid I'm having difficulty following what you are trying to say. ΔνCs is an emergent quantity, that is directly determined by all the fundamental constants (in a hypothetical correct model), but is used experimentally as a time reference. Notice that ε0 does not occur in the list either, but is also considered fundamental (as would be any function of fundamental constants). That there are a few constants in common should not be taken as that there is anything special about their status as fundamental constants. All that we could say is that the SI constants are in principle fully determined by whatever list of constants one chooses as the "base" fundamental constants, but I'm not sure we should even do that. —
Quondum17:44, 10 January 2024 (UTC)reply
The article current mentions kilogram based two values, h and c, listed among the ones on Uzan's list and one not listed. I think a legitimate question by readers would be: "Why isn't it listed?" I'm saying that if "ΔνCs is an emergent quantity, that is directly determined by all the fundamental constants", it is not evident to readers.
Johnjbarton (
talk)
18:15, 10 January 2024 (UTC)reply
Okay, so the narrative you might be looking for is that since 2019, the SI is in principle wholly determined by fundamental constants. Three of the SI dimensions (temperature, amount of substance, and luminous intensity) are technically determined by the other four, and can be ignored. Two are directly from the list (c and h), one is directly determined (e, directly determined by the coupling constants of the gauge groups or may even be one of them, or so I guess), and the fourth is an emergent property of a complex system, namely a caesium atom, whose properties are in principle determined by the fundamental constants but which is beyond us to derive. We realize those units by using physical properties that are directly related to these constants, aside from the experimentally determined property of the caesium atom. —
Quondum20:22, 10 January 2024 (UTC)reply
Yes, it is quite a mouthful just to put in anticipation of the reaction to the SI happening to have moved in this direction – and kinda off-topic. Maybe we should actually trim down what is said on the SI to, in effect, that the SI has moved towards using fundamental constants in preference to artefacts for defining units? —
Quondum01:57, 11 January 2024 (UTC)reply