Talk:Quantum mechanics

Density function image

I've made a newer version of the density function image, i think it should replace the old one.

Hydrogen

Yey or ney? —Preceding unsigned comment added by PoorLeno (talk • contribs) 22:54, 16 August 2008 (UTC)

I really like your new graphic and would like to see it in the article. However, what would be very cool is to go through the derivation. The only example on the page is the very simple 1-D point. Going through Hydrogen's derivation would be a great addition. Speedplane (talk) 17:42, 30 June 2009 (UTC)

The derivation is unfortunately a little complicated, possibly too complicated for a wiki article. One of the better explanations is here: [1] StuartH (talk) 04:29, 24 March 2010 (UTC)

"Quantum mechanics" vs. "quantum physics"

As scientists generally regard the term "mechanics" as a deprecated term and prefer to use "physics" instead (correct me if I'm wrong, this is the view held at Stanford), I think we should consider changing the name of the article accordingly. GarconDansLeNoir 16:19, 1 June 2007 (UTC)

IMHO mechanics is that part of physics that deals with point particles, in contrast to field theory which deals with fields. Also, doesn't "quantum mechanics" more refer to the theoretical foundation of operators and Hilbert space, while "quantum physics" is a very broad term encompassing all physics on atomic scales? Just my personal impression, might as well be biased. - Saibod 09:07, 2 June 2007 (UTC)

As a grad student in chemistry (specializing in quantum), I think this is a non-issue. I have not observed any discussion in the "scientific culture" to which I belong regarding the distinction between "quantum mechanics" and "quantum physics." Of course, as a student I am more concerned with learning it than what it is called. Any more thoughts?--Leiding 15:05, 4 June 2007 (UTC)

The "mechanics" part of "quantum mechanics" is a pain in the ass. QM tends to be used to refer generally to any kind of quantum physics, even if that's not quite accurate. I agree the language is bad, but I think it would be needlessly confusing to Wikipedia's audience if we changed the article's name (presumably by moving this article to "quantum physics" and redirecting "quantum mechanics" there since that's what everyone would look for). Gnixon 01:40, 13 July 2007 (UTC)

I see it as quantum theory which is founded on a description of physical systems by vectors in a Hilbert space which undergo unitary time evolution. It can be viewed as a framework for theories, rather than a theory itself. When quantum theory is applied to systems whose degrees of freedom correspond to what would classically be covered by mechanics (i.e. the position and momentum of an object) the result is quantum mechanics. When quantum theory is applied to dynamics which include fields the result is quantum field theory and so on. Personally, I would like to see quantum theory used when the general theory is meant, whereas quantum mechanics and quantum field theory should refer to the "application" of quantum theory to mechanics and field theory, respectively. I emphasize, however, this is merely my opinion. 69.140.13.88 (talk) 23:11, 6 January 2010 (UTC)Nightvid

Further develop or exploit

User:DVdm The original formulation seems to me to be better because Einstein's ideas differed markedly from Planck's. Where Planck saw quantization as a property of the interaction between atom and electromagnetic field, was Einstein's idea that it is a property of the field alone. Nowadays (rightly or wrongly) Einstein's idea is universally accepted.WMdeMuynck (talk) 10:34, 22 January 2010 (UTC)

Ok, can live with that. DVdm (talk) 11:11, 22 January 2010 (UTC)

Removed long-standing apparent vandalism

Someone recently reinserted the name Abdus Salam in the list of physicists who developed electroweak theory. I was curious how this name was left out, and why the name "Carl Jamieson" was a redlink. As far as I can tell, there is no such (famous) physicist. It appears that this edit was the culprit and was an act of vandalism. It is sad that such an error could persist in an article of this importance for half a year! It appears to have gone undetected for so long because someone else was in the middle of a bunch of edits at the time. CosineKitty (talk) 02:05, 17 February 2010 (UTC)

Not really vandalism

Hi. I made some changes to the page yesterday that were rapidly reversed and treated as vandalism. I'm new to wikipedia, so forgive me if I've gone about making the changes in the wrong way. I intend to re-introduce them gradually, subject to getting advice to the contrary through this discussion page. By way of background, I have a PhD in quantum theory, so I know something about the topic.

The first sentence on the page currently reads as follows, with my comments inserted: 'Quantum mechanics (QM) is a set of scientific principles [this is un-necessarily vague- quantum mechanics is a branch of physics] describing the known behavior of energy and matter [QM does not describe all the known behavior, although it does describe most of it. Also, it describes those behaviors more accurately than any other collection of theories, so that ought to be made clear] that predominate [the words 'that predominate' are superfluous] at the atomic and subatomic scales. QM gets its name from the notion of a quantum [that is not a helpful explanation- its like saying that classical mechanics gets its name from the notion of classicism], and that quantum value is the Planck constant [plank's constant is not 'the quantum value', it is just the ratio of energy to frequency of a single photon]. Given the reasons I've stated here I will edit the first sentence accordingly unless someone talks me out of it.

Best wishes —Preceding unsigned comment added by 81.129.41.235 (talk) 20:22, 25 February 2010 (UTC)

Hi! This is an unfortunate welcome to Wikipedia. What happened here was understandable but not very friendly. I did not revert your edit, but the reason was probably because somebody saw an IP address edit (81.129.41.235), coupled with a large section of text changed. We are swamped with people vandalizing Wikipedia articles, and 9 times out of 10, it is someone editing with an IP address. I also notice that at least half of the edits made by IPs are vandalism. The amount of change you made all at once, along with the IP address was (unfairly) a red flag that caused this immediate knee-jerk reaction. Take a look at how your edit looks to people like me who are on the lookout for vandalism: diff. They see lots of stuff changed, the fact that you removed references (the "Tag"). Here are some ideas you can try to avoid the knee-jerk reaction:

1. Make a few uncontroversial and minor edits first.
2. Type in an explanation in the "edit summary" box when you commit the change, so people understand where you're coming from.
3. If you want to make lots of changes, try discussing here what you want to do first and see if there is any objection to it. Wait 3 or 4 days for long-time contributors to have a chance to find it and weigh in.
4. Create a named account for yourself. If you do, put a sentence or two on your new account's user page, so your user name isn't a "redlink". (Yes, this is dumb, but it is a red flag that makes the old-timers instinctively suspect vandalism.)

I'm sorry if this was off-putting, and we could definitely use more people like you here! CosineKitty (talk) 02:42, 26 February 2010 (UTC)

Error in introductory paragraph

The introductory paragraph includes the statement, "The name derives from the observation that some physical quantities—such as the energy of an electron—can be changed only by set amounts". This is only true of bound electrons in atoms and molecules (and their ions), free electrons are in the continuum and their energy can take any value.

"The name derives from the observation that some physical quantities —such as the energy of an electron bound into an atom or molecule— can be changed only by discrete amounts".

Note also that I changed "set amounts" to "discrete amounts". I find this a better description because of the equivalence of 'quantization' and 'discreteness'.

I would just make the change myself, but this being the introduction of an important article I would welcome any comments before doing so.

--DJIndica (talk) 15:48, 4 May 2010 (UTC)