Talk:Quantum number/Archive 1

Untitled

The article lacks a clear, general definition of a quantum number and relies too much on specific examples. The intro sentence about conserved quantities is nice, but isn't there more to it than this? Shouldn't quantum numbers provide a minimal set of labels that fully specify the eigenstates of a Hamiltonian? The article also says quantum numbers are discrete. Is this always true? What if we are considering a free Hamiltonian. Is there a notion of quantum number? If so, they should be continuous. — Preceding unsigned comment added by Syhpwikiphys (talk • contribs) 22:17, 25 May 2016 (UTC)

It says 'there are three quantum numbers for the hydrogen-like atom', then lists four.

I tried to clean that up a bit. The reason is, that the analysis is simply wrong and produces only three. That is not an error in the article, but an error with the historical version of quantum mechanics at the time the analysis was done.

A hydrogen like atom has three quantum numbers. An electron in a hydrogen like atom has four quantum numbers. kaspuhler

Can we have an explanation for why spherical symmetry of the Columb potential means the Hamiltonian must commute with J^2?

This is a really pathetic stub. Adding to cleanup. -- The Anome 08:37, 17 Mar 2004 (UTC)

How is it pathetic? It's a stub, not a full article. It's an important piece of physics and deserves a definition. I just don't have the time right now to write the 1,000 word article that could easily go here. dmmaus 08:44, 17 Mar 2004 (UTC)

That's what I'm suggesting. It needs the 1,000 word article! -- The Anome 08:47, 17 Mar 2004 (UTC)

Ah, sorry. I'm still relatively new and didn't realise exactly what cleanup was. Now I know! :-) dmmaus 08:51, 17 Mar 2004 (UTC)

This article is pretty confusing to the average kid who's just learning about quantum numbers...I came to this article to refresh myself on the 4 quantum numbers I learned in basic chemistry and saw a bunch of Greek and sub-particle stuff. I'm gonna add a beginner's guide to quantum numbers. EDIT: there are articles in the "External Links" which may give this information too but there should be a note somewhere in the article that refers to these. I will save the information I typed and whoever knows more about this than me can do with it what they want-- Bubbachuck 23:55, 23 May 2005 (UTC)

This is an encylopedia article, not an introduction to quantum numbers geared towards a highschool chemistry student, which, for your information, I happen to be. -- Rmrfstar 22:32, 9 Jun 2005 (UTC)

i'm not sure what you're getting at by telling me your a highschool chemistry student...are you saying that the article is too complex/not complex enough for you? i'm a junior in college and I've taken gen chem, organic chem, physics, etc. (i'm an engineer) and without sitting for half an hour, I can't understand this article. with no disrespect to the author(s) of the article in its present state, but it reads like a quantum physics or physical chemistry textbook, not an encyclopedia article. Take the opening definition, for example, "A quantum number is any one of a set of numbers used to specify the full quantum state of any system in quantum mechanics". I'm sure its in accurate definition, but not one that someone with a basic knowledge of chemistry or physics will understand (which in my opinion, they should be able to). Bubbachuck 20:08, 23 Jun 2005 (UTC)

The point I was trying to make was that this article is not supposed to introduce, "the average kid who's just learning about quantum numbers", to the subject, but to provide encyclopedic information about quantum numbers, such as the correct definition. By stating my level of education, I was simply showing that from my perspective, one would want the article dumbed down, however, I do not. I do think however that the article should be expanded to include better alternative (not neccessarily simpler) definitions of what a quantum number is. It seems to me that you want a textbook, to introduce you to the subject, rather than an encyclopedia article, to describe the subject. -- Rmrfstar 21:43, 23 Jun 2005 (UTC)

your opinion is unwanted and unencyclopedia like.

Are we getting the signs right? In the 'Quantum numbers with spin-orbit interaction' section, it says, the state j=1/2, mj=-1/2, odd parity is coming from state (8) above, which has l=0, but then the parity should be (-1)^l=+1, thus even, no? -- Rafi from 134.107.4.116 20:09, 3 December 2007 (UTC)

You're correct Rafi, the even and odd were reversed. States coming from l = 1 have odd(-1) parity while states coming from l = 0 have even(+1) parity. p = (-1)^l etc. I have edited the article to correct this. --jeCi If "Bob" were a hamburger you couldn't finish the whole thing... (talk) 01:08, 22 February 2008 (UTC)

Link that links to nowhere

The link "Quantum numbers and electron configurations" under "Atomic Physics" does not work. I propose to change this link to Pictorial Representation of the quantum numbers n, l and ml. I think it provides excellent illustration of how those three quantum numbers relate to each other. We can always add the old link back when it is fixed. Any objections? Drova (talk) 04:10, 24 August 2008 (UTC)

Removed, as it appears incorrect. It might be feasible to restore the old link with a {{dead link}} tag, but this one is just wrong. — Arthur Rubin (talk) 13:01, 29 October 2008 (UTC)

OK to restore both links. The linc in question was correct. —Preceding unsigned comment added by Drova (talk • contribs)

Why does perfectperiodictable not violate WP:ELNO#11? — Arthur Rubin (talk) 22:15, 29 October 2008 (UTC)

Well,Arthur, let experts here express their opinions. You have already expressed yours. Please, tell us exactly what is incorrect about it. Would you?68.48.234.55 (talk) 02:15, 30 October 2008 (UTC)

First, even if it were correct, it's a personal web site by someone who is not apparently an expert. ELNO#11 suggests that it might be allowable if the expert (in the appropriate field) has his/her own Wikipedia article.

If it were correct and not considered beyond fringe, it would be an alternate labeling system (I wouldn't go so far as to call it a "quantum number"ing system, although others might) using the quantum numbers n+l, l, and m_l (or perhaps m+l), instead of the standard n, l, and m, with a questionable mnenonic device.

I'll defer to others as to the question of whether it's correct, as my expertise only derives from courses at CalTech. — Arthur Rubin (talk) 18:28, 30 October 2008 (UTC)

I am no sure what do you mean by (m+l). I've never heard of it. Also, there is no such quantum number as m in atomic physics. The mnemonic device is not questionable. It is just another representation of the Madelung rule, only in 3D. WP:ELNO#11 does not prohibit such links, although it recommends to avoid them.Drova (talk) 19:54, 30 October 2008 (UTC)

Fine. Let's avoid them, then, especially in article where they wouldn't belong even if published. Such as this one. — Arthur Rubin (talk) 17:49, 31 October 2008 (UTC)

Quantum number s

What about the quantum numbers s? Why isn't this included on this page? Also aren't there cases where m_s = 1 etc? such as the spin of it is discover by the great sciencetist hund mulikan they told that there are four types of quantum number 1>principal quantum number<n> 2>azimuthal quantum number(angular quantum number)<l> 3>magnetic quantum number<ml> 4>spin quantum number<ms>

Not all quantum levels present in spectrum?

According to this image at university of Florida

which is summarized in this table

j	ml	ms
3/2	1	1/2
3/2	0	1/2
3/2	-1	1/2
1/2	1	-1/2
1/2	0	-1/2
3/2	-1	-1/2

only the levels highlighted in yellow are represented in the spectrum.

	n	l	ml	ms		l + s	l - s	ml + ms
#1.	2	1	1	+1/2		3/2	1/2	3/2
#2.	2	1	1	-1/2		3/2	1/2	1/2
#3.	2	1	0	+1/2		3/2	1/2	1/2
#4.	2	1	0	-1/2		3/2	1/2	-1/2
#5.	2	1	-1	+1/2		3/2	1/2	-1/2
#6.	2	1	-1	-1/2		3/2	1/2	-3/2
#7.	2	0	0	+1/2		1/2	-1/2	1/2
#8.	2	0	0	-1/2		1/2	-1/2	-1/2

I am sure that I must be missing something.

I guess it probably has to do with selection rules.

parity should be inverted

Δm_s = 0

Δl = ±1

Δm_l = 0,±1

Δj = 0,±1

Just granpa (talk) 23:12, 19 December 2010 (UTC)

"The question of how many quantum numbers are needed to describe any given system has no universal answer, ..."

and then...

"To completely describe an electron in an atom, four quantum numbers are needed."

Contradiction?

Matt

Mrweber111 (talk) 03:34, 6 March 2011 (UTC)

Symbols, math and layout

The use of symbols on this page was very incoherent; <math> mixed with regular text, some in italics and others not. I've attempted to clean it up, please review my edit and fix any errors. A number of things are still open:

• I dislike he use of italics; symbols or not normally required to be italic and we shouldn't use it if it's not required.
• The symbol "ℓ" was used in the <math> version of symbols, but the basic "l" is used in the text. I've assumed it should be "ℓ" and that the author was unable to create the symbol in normal text.
• I'm not sure about the use of commas and ellipsis in series - there was mixed use in the text before. I'll have to check the MoS, but haven't got time right now.

    — SkyLined (talk) 11:09, 3 August 2011 (UTC)

Since there was no reaction, I'll assume nobody objects to me applying whatever style I think works best and/or follows MoS. Let me know if you see any edits by me that you feel are not improving the article.     — SkyLined (talk) 17:43, 12 November 2011 (UTC)

Beh, don't have enough time to do this now... I may revisit this later :(     — SkyLined (talk) 17:46, 12 November 2011 (UTC)

It doesn't matter if you dislike italic for symbols - they help to match the equations and stand out from the upright background text, Wikipedia:Manual of Style/Mathematics uses italix, and it generally looks unprofessional to just leave symbols for specific quantities upright. Although I certainly agree that using LaTeX (i.e. <math> </math>) for symbol is too much and incoherent, and would like to thank you for clearing up those messes. =)

One problem with this article was that the important mathematical statements were buried in the text and not presented clearly - forcing the reader's full attention to look through the paragraph instead of making it easy. I have italixed the variables and extracted the formulae/number values and made them big, since I didn't want to destroy your html/template formatting.

Furthermore commas and ellipses in series are no problem, this is used in textbooks and how else can we write a list? F = q(E+v×B) ⇄ ∑_ic_i 11:18, 5 May 2012 (UTC)

Blend first two bulleted lists, nuclear spin?

There is no point in the seperate and repeated subsections Traditional nomenclature and As applied to the Hamiltonian and Schrödinger equation. The quantum numbers should be stated and explained, then summarized, so those bulleted lists should be merged. Also there is no mention of nuclear spin I and its quantum numbers. I intend to add this. F = q(E+v×B) ⇄ ∑_ic_i 08:49, 5 May 2012 (UTC)

Quantum Number and Fibonnaci sequences

As part of a larger project to work out hitherto unknown mathematical relationships in the periodic system (at both electronic and nuclear levels) I've found a new pattern relating directly to quantum numbers and the structure of the idealized quantum mechanical tabularization of the periodic table. As original research I thought to put it here for the moment, and be brief about it as possible.

Before this it was also discovered that many of the numerical relationships in the periodic system related to the classical Pascal Triangle (values from its deep and shallow diagonals) as well as those from sister Triangles (with different side values)- nearly two dozen so far.

Then, recently, I realized that simply by mapping generalized Fibonacci sequences one atop the other (so that inter-row differences were always fixed Fib numbers, such differences being in the same sequence as the Fib sequence between columns) gave values that directly relate to the construction of the table's blocks as well as to quantum number values.

Consider: a:0, 1, 1, 2, 3, 5,... b:1, 2, 3, 5, 8, 13,... c:2, 3, 5, 8, 13, 21,... d:3, 4, 7, 11, 18, 29,... e:4, 5, 9, 14, 23, 37,...

The first column represents quantum number l (thus every row defines a new orbital type), the second column the quantum number n where the l value first appears as well as the first position in the orbital row defined by quantum number l where the quantum number ml first has value 0. The third column shows the number of elements in the half-orbital row, and the period number in the Janet Left-Step Periodic Table where these numbers first appear. Column four gives the second position within the orbital row where ml=0. For the Janet table these numbers work forever, row by row. — Preceding unsigned comment added by 69.121.117.192 (talk) 07:53, 29 May 2012 (UTC)

"q-number" redirect and possible ambiguity of "quantum number"

"q-number" shouldn't redirect to this article, because "q-number" is the old terminology of Dirac for non-commuting numbers a.k.a. operators which is not the same as the quantum numbers discussed in the article at hand. This is correctly mentioned in the article C-number. I just leave this as a suggestion because I don't have time to find a proper source right now.

Confusion

I find this article very confusing. I am trying to understand the relationship between quantum numbers and invariants, and the article doesn't help me much. Examples of the difficulties I'm having:

• Are quantum numbers associated with states, observables, or both?
• Are all quantum numbers a consequence of Noether's Theorem, or just topological quantum numbers?
• What is the role of symmetry, and which numbers are associated to which symmetries (global, local, internal)?
• Is a quantum number the same thing as a quantum invariant? — Preceding unsigned comment added by 70.247.162.108 (talk) 13:45, 5 June 2015 (UTC)

Additional confusion

Article also mentions spin quantum number (s), and then goes on to describe spin projection quantum number (m_s). Are these the same thing? If not, how are they related? — Preceding unsigned comment added by 70.247.162.108 (talk) 13:52, 5 June 2015 (UTC)