Talk:Quantum mechanics explained

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Currently, this is only a draft. The order of the sections may be changed, many parts of the current introduction should be moved to other sections. Some parts are probably still too sketchy. --DenisDiderot 20:36, 25 December 2005 (UTC)

Contents 1 Images 2 Couplings of modes 3 Heisenberg picture 4 More resources for the article 5 Basics of quantum mechanics 6 Move to Wikibooks

[edit] Images

I think it would be nice to put some images into the article illustrating the analogies (of course, we must ask the owners of any pictures for permission):

• some one-dimensional example of a standing wave on a spring or a string
• Chladni's figures, maybe this one: [1]
• electronic orbitals
• optical modes in an microcavity lasers, e.g. [2]
• laser modes, e.g. [3]
• some picture demonstrating the filling of orbitals in multielectron atoms that does not use orbits
• some Feynman diagrams and a picture illustrating spontaneous and stimulated emission
• pictures about coupled pendulums, chemical bonding, energy bands in semiconductors for the new section about couplings

--DenisDiderot 20:25, 25 December 2005 (UTC)

[edit] Couplings of modes

There should be a section about coupled pendulums, the anticrossing principle in two-level systems and its many applications in quantum theory, e.g. in chemical bonding, solid state physics (energy bands) etc. It is very important to understand which of the couplings of modes are relevant and which are not. There could also be a sentence mentioning the role of symmetries in ruling out possible couplings. --DenisDiderot 20:25, 25 December 2005 (UTC)

[edit] Heisenberg picture

In quantum mechanics an observable is directly measurable. It is related to the system under consideration by an operator. The system under consideration is characterized by its state, denoted by a state vector.

In the Heisenberg picture the state vector, |ψ> does not change with time, and an observable A satisfies

In the expression above, the commutator [A,H] bears a formal resemblance to the Poisson bracket (denoted ) description of the time evolution of a classical system:

In my view, the Heisenberg picture might be historically significant, but I consider it a purely mathematical technique, which is not necessary for understanding any new physical idea. In practice, the interaction picture is more important. Here's a suggestion for mentioning it in words without introducing many new concepts in the explanation - see the article.

Concerning the formalism: I suggest we avoid using the formalism in most sections of the article, because it is only understood by people who already know very much about quantum mechanics, and these people don't need this Wikipedia page, except maybe for looking up information they forgot. But for the latter, specialized pages like Heisenberg picture are more suitable. But nevertheless it might be a good idea to add a section to the end of the article about the formalism and its connection to the concepts introduced in the other sections (including the quantum field theoretic concepts), because after understanding the idea, many people might be eager to know how all this looks like in formulas.

--DenisDiderot 12:20, 26 December 2005 (UTC)

[edit] More resources for the article

DenisDiderot,

I found a 'Quantum mechanics - simplified' article which has some nice pictures and context for the Planck black body radiator, but which does not use the resonance analogy; it uses a one-dimensional version of the wave resonances of the QM explained article here. One possibility is to merge this with the 'QM explained' text.

I agree that the Heisenberg formula is not needed; I was trying to set the stage for a theme, which is the non-spatial nature of the formula, which then neatly explains non-locality. But there are then 3 themes in one article which might then be a problem:

1. 1-d spatial wave (QM simplified)
2. resonance/2-d spatial wave (QM explained)
3. non-local (non-spatial interaction) (Heisenberg picture).
   

   

   A sketch to justify spectroscopy observations for certain atoms

My thought on the similarity of resonance and non-local is that at atomic and nuclear scale, the size of the walls for the resonance is the size of the potential well at atomic/nuclear scale, which are the walls of the 'cavity resonator', but that the QM comes out purely from the size/shape of the walls of the resonator. 1-D and 2-D/3D fit nicely together.

Then the non-local approach can handle spin and other non-spatial quantum numbers which have an unknown interaction/scaling distance for the range of their 'forces' (in other words, we have not yet seen the width of their resonating container, if that concept is appropriate at all). The role of time in all this is as the parameter which 'orders' or 'unifies' the states. In other words, it is as if our concept of 'space' yields to new interpretation, while our concept of time still remains, for QM.

I can't spend more time working on this right now as I have some deadlines to meet. --Ancheta Wis 02:25, 28 December 2005 (UTC)

Ancheta Wis 16:38, 29 December 2005 (UTC): Found an image (shown above) for the anharmonic oscillator that Heisenberg and Bohr were attempting to explain:

Thanks! Unfortunately, I also have a deadline. In three weeks I'll have a little more time. --DenisDiderot 00:54, 30 December 2005 (UTC)

[edit] Basics of quantum mechanics

I don't understand the relationship of the pages. I do think there should be a variety of levels, but the order is not immediately clear, nor is it clear to me that there should be another classification of articles than depth. If this is intended to replace that page, which I favor because that page is too historical for a general introduction, that should somehow be immediately obvious. How about renaming "Basics of quantum mechanics" to "history of qm" and this page to "Basics of quantum mechanics" ? In other words, I don't see a destiction between qm and its explanation. David R. Ingham 11:01, 12 February 2006 (UTC)

This is an attempt of a more didactical introduction to quantum mechanics that is comprehensible for the layman but nevertheless exact. Next week, I'll have more time to continue working on the page. --DenisDiderot 09:48, 13 February 2006 (UTC)

[edit] Move to Wikibooks

This seems outside of the scope of an encyclopedia. Comments? —Ben FrantzDale 19:33, 21 April 2006 (UTC)