Talk:Introduction to quantum mechanics/Archive 1

message: I am trying to expand this article into something fairly thorough, and I welcome comments and suggestions. Of course anyone can contribute directly to the article, but if it helps I'll volunteer to coordinate things; so, maybe we could cont ribute to the discussion before editing the article? For what it's worth, I have no philosophical axe to grind so I will be writing very carefully, neutrally, and simply as much as possible.
I will initially simply try to add structure and clarity.
I in tend eventually to expand this into simplified versions of many major technical articles. Frankly, the quality of most scientific articles I've seen here is VERY poor IMO as encyclopaedia articles. They may be of a "high" standard technically, although th at's open to debate, but they are way below what I would expect as a real explanation of what the subject means to a general audience. Many seem to be written by specialists for specialists without any regard for beginners, children, laymen, non-native En glish speakers, etc.
Paulc1001 06:38, 5 October 2005 (UTC)
thread_title: my attempt

message: I think we should illustrate the importance of quantum mechanics by virtue of a list of things that are done with QM, starting with input from the main QM page:
*Used to help describe everything from the subatomic particle to the universe as a whole.
**Speculated that QM will help describe black holes, gravity and other mysteries of the universe.
*Help in combining molecules to form chemicals - quantum chemistry.
**Showing which molecules are energetically favorable to which others, and by approximately how much.
*Modern technology
**The laser, the transistor, the electron microscope, and magnetic resonance imaging.
*Future research
**Quantum cryptography, quantum computers and quantum teleportation.
Grika Ⓣ 18:28, 6 October 2005 (UTC)
thread_title:  Uses 

message: Quantum gets personal I would very much like explore the more personal yet no less fantastic sensory applications of quantum physics. This would include the relationship of the effect of an immediate visual sensory absorption of, let us say, a rainbow in the sky, with the memory of this beautifully natural event. After the rainbow is gone, the memory of the rainbow activates the exact same neurons in the brain as the first observation through sight. Add to this the notion, under quantum theory, that there is no stable "reality" underlining the material world. We relate everyday, as we drive our car, eat, interact and sleep to expected, dependable material objects surrounding our existance. However, are these realities only a manifitestion of an impressionable mind? Is it possible that, given the constant movement of electrons, prot ons and neutrons within the atom, that each one of us determines the possibilitiies of formed matter, at a given time, given our previous relationship with similar observations. Can the same object exist in two places at once? Our world around us is chang ing all the time, and it reacts to our imposition, and creates an impression that is as real tomorrow as it is today. There are no absolutes. We can change the world!
--71.12.188.255 22:50, 10 October 2005 (UTC)
thread_title:  Quantum gets personal 

message: This article was debated on AfD, with the result of Keep. The closer's comments: "This is a rather tricky one. 19 people expresed definate opnions. Of these 6 or 32% chose a simple keep as their first option, 3 chose a rename (which two others listed as a second choice), and 2 a merge to an existing article, for a total of 11 or just under 58% for keeping on en.wikipedia in some form, with a simple keep the mos t common chice among those 11." The AfD debate may be found at Wikipedia:Articles for deletion/Quantum Mechanics - simplified.  DES (talk) 18:30, 18 October 2005 (UTC)
thread_title:  AfD result 

message: I am a little unsure of how to procede to make multiple changes that would not change the meaning of the article as it stands, but only remove some of the language problems.  Should we copy the whole article to this discussion page and then mark desired changes on that version? Should we put a separate version in a sort of sandbox file and work on that?  If an article gets contentious that might be a good way to preserve "the last version that everybody could basically agree to" while the new issues are fought o ut backstage. That's better than a series of edit wars that make the reader's version dependent on whether s/he looked the article up at 12:00 or at 12:01 or at 12:03.  But it hardly seems worth it to change a misused "which" to "that." P0M 05:19, 19 December 2005 (UTC)
thread_title:  Suggestions for editing the current version. 

message: I was considering possibly adding more material, but I don't think this should be a textbook.  We haven't covered the tunneling through effect and the definition of a matter-wave, Quarks and Leptons, Bosons and Fermions, Particles and Antiparticles, Symmetry and CP Violation, and atomic forces i.e. weak, strong, electromagnetic.  These are part of QM, but I don't want to bog down the article.  These could be easily explained in everyday English.  The articles in Wikipedia dealing with these subjects amount mostly to mathematical equations and don't explain much.  I could start a new section called "Advances in quantum mechanics".  But I'm not sure how much to include.  Any thoughts?  Anyone?--Voyajer 23:29, 28 December 2005 (UTC)
thread_title: Where do we stop?

message: I like all of the illustrations, but I think that Heisenberg's_Uncertainty_Principle_Graph.png is too small. I can barely read the text.  Wikipedia was originally a little stingy with file sizes and then about a year ago somebody must have realized that they were tossing away a good bet. Why take a 2x3 picture of a black widow spider if you could get an 8x10 version. Now they don't even want anything with lossy compression. I am sure they have re alized the archival value of good pictures.  Diagrams are a little different since one could theoretically scale one up and then edit the image to get rid of the jaggies, etc., but that is a really messy, time-consuming job. (I do the equivalent thing som etimes when I am making special images from photographs.) If I am making an image having no great amount of detail, no need for especially accurate colors, etc., I will sometimes make a large gif image to save file size.  Anyway, a larger image would alwa ys be acceptable and you can specify 340px or something like that to get it down to a reasonable size. You can also put in a "magnifying glass" to remind users they can see the full-sized image by just clicking on it.  
I hadn't thought of it before, but some Wikipedia readers with poor vision may be using the view menu on their browsers to make the print large enough for them to read. People with limited vision would be especially appreciative of large diagrams. I could easily enlarge the image, but if you have a larger image it might be better to just upload that one. One other thing, are you uploading your images to Wikipedia Commons?  If you do it that way, then you will make your stuff available world-wide without the need for somebody in China or w herever to copy your image and then put it on their server. P0M 05:48, 29 December 2005 (UTC)
replies: text: If you download the high resolution version you can read it without any problem. It looks like it must be a scanned wall chart. If I were doing it, I would probably just show a "det ail" of the whole chart that people could actually see without blowing it up, and then let them know that they could link to more complete diagrams. As it is, it's kind of like the Lord's Prayer on a grain of rice.
**Well perhaps we should pray over it t hen? :-) ---Voyajer 02:52, 30 December 2005 (UTC)

text: That reminds me of a science fiction story in which somebody discovered that the entire wisdom of a higher intelligence (oh, oh) had been written in coded form in the junk DNA shared by every human. I don't recall that it explained the human appendix and other such mysteries, however. P0M 03:23, 30 December 2005 (UTC)
thread_title:  Illustrations 

message: In the current version of the article it says:  "So the reduced Planck's constant gives the energy of a wave in packets per radian instead of packets per cycle."  I think one could speak of "conventional units of energy" where you have "pa ckets," but could not substitute "quanta" for "packets," which is what I suspect you mean to do.
My understanding is that when a photon (quantum of light energy) strikes an electron it will either be reflected in a perfectly elastic way or else the photon will be absorbed and the electron will jump to a higher orbital.  If the electron falls to a lower orbital, the energy differential will appear as a photon.  If conditions are right, the electron could immediately accept another energy boost, jump to a higher orbital, shed its energy as a photon, and in this way a "train" of waves would Each cycle is a kind of mapping of the rise and fall of one electron one time. So each cycle can carry only one quantum of energy, and the color of the light is an indication of the amount of energy characteristic of that frequence of light.P0M 08:09, 30 December 2005 (UTC)
thread_title:  Question regardin g "packets" 

message: I just moved the article. The change didn't show up in my watchlist, so I will notify you  individually. Things may be a little slow in the system. Have you been getting lots of "session info lost" errors? P0M 20:06, 30 December 2005 (UTC)
thread_title: Moved

message: To those interested (and certainly there are many following this article who are) QM has had many detractors including Albert Einstein and Erwin Schroedinger.  QM has had a profound affect on philosophy.  Immanual Kant wrote about the philosophy of determinism derived from the ability to predict future outcomes in the universe (such as future position of planets) by science.  QM took away predictability and therefore was a blow to philosophy.  THEREFORE, without going into religious philosophy, I will be beginning an article entitled Quantum mechanics, philosophy and controversy within the week.  It should be an interesting study and I welcome contributors.  Of course, however, with the usual caveat as with all physics articles, please restrict links and contributions to science and philosophy disregarding any religious implications. The freedom of religion act show allow each individual to draw their own religious implications from science and none should be thrust upon them by implying any particular religious view can be drawn from them.  I say this in advance knowing the impact on religion that science has always had and the impact that QM had on believers in fate.  I look forward to beginning the article and to your contributions.--Voyajer 18:53, 1 January 2006 (UTC)
thread_title: Regarding the effect of QM on philosophy and its controversies

message: I made no claim that quantum entanglement follows classical laws at 10 Km with a "finite speed". It is true that verification of an entanglement result would have to be made using a classical channel for the information.
The disclaimer was merely to stop thoughts that entanglement allowed communication faster than light. In order to verify the entanglement, classical communication channels are needed. That was what I was trying to state in the prose. But my phraseology is immaterial. The disclaimer is the important thing -- no results that break the speed limit. No free lunch. The classical channels are necessary for the rest of us, even if A B were entangled. The rest of us wouldn't know it until we could perform a classical verification.
:I don't follow this argument.  Before I forget about it, let me say that the difficulty with communicating as proposed is that (as far as I know) there is no way to set the photon.  It makes a difference whether one can set the state of one of two entangled protons, or whether one mere discovers the state of one of the protons.  Measurement involves a physical operation that changes things, but maybe there is indeed some way to coerce the appearance of one state or another in the local particle.  Assuming this to be the case, and assuming that one could transport one half of a Janus pair at sub-C velocity, then one could use a simple code system. Once humans get to the remote star, if they need to warn earth of an approaching attack fleet by aliens who now know where we are, then we'll send one signal, and if nothing is threatening, we'll send the other signal.  You couldn't do that with a photon unless you established a communications system midway and beamed pairs ahead toward the new colony and back toward earth. The new colony could then "flip" the arriving photon, assuming it could somehow be distinguished from all the other photons, and the other half of the pair could be examined on Earth.  This method strikes me as being about as primitive as the early system of signal beacons used in China to warn the capital of trouble on the frontier. 
:Anyway, back to the argument above.  Why would one need to "verify the entanglement"?  If the method works reliably in the laboratory, it should be possible to scale it up.  Then if a few pairs could be employed, one could simply check for a consistent message on most or all of these "channels." P0M 01:15, 3 January 2006 (UTC)
thread_title: Classical channel

message: I have just seen the analogy to a see-saw. That explains a previous statement in the article, but there doesn't need to be a compensating up/down for a down/up. It is more like up/up followed by down/down. I quote from Aczel's restatement  (p.226) of 3 entangled particles. The formulas are the same whether the particles are photons with +1, -1 polarization, or particles with +1, -1 spin. The following experiment was designed by Michael Horne using polarization as the entangled property: 
A source emits 3 entangled particles A B C simultaneously. A B C pass simultaneously through three sets of two slits a,a'     b,b'     c,c' at the same time. Each part of slits are given a set of beamsplitter settings (Left or Right =L or R). A precise set of QM predictions exists: Up or Down = +1, -1 in detectors D_a,D_a'    D_b,D_b'     D_c,D_c' for 3 entangled particles A B C. All the particles can be in the same state +1 or -1 after the detection. Given specific outcomes for B C, then A is known with certainty. (Aczel p227.)
Condition and Predicted state. 
A B C Settings.	n particles in -1 state.
R L L          	0 or 2
L R L          	0 or 2
L L R          	0 or 2
R R R          	1 or 3
The end result, which has been clearly stated in the Entanglement article, is that locality is violated. A B C are entangled at a distance from each other. But that was not the point of this note; the point was that the entanglement doesn't have to be a seesaw up/down for down/up. It is more like the '0 or 2' versus '1 or 3' particle outcomes as stated in the table above. Which outcome? -- we don't know until the experiment is performed.
 Greenberger, Horne, Shimony and Zeilinger (Dec. 1990) "Bell's Theorem without inequalities" American Journal of Physics 58.12 pp1131-43, appendix as referenced by Amir Aczel (2003), Entanglement p.222 
 Michael Horne (2001) "Quantum Mechanics for Everyone" Third Stonehill College Distinguished Scholar Lecture May 1, 2001 p.4. as referenced by Amir Aczel (2003), Entanglement p.224 
--Ancheta Wis 22:03, 2 January 2006 (UTC)
thread_title: 3 particle entanglement

message: I have made a lot of changes on the entanglement section in order to reflect what I think is correct and verifiable and uncontroversial. It will be interesting to see whether people largely agree with me. I plan to refine my edits by addition of references and wikipedia links, in the near future. Underlying my edits is my knowledge of Bell's theorem which derives a contradiction between quantum theory and classical theory, using entanglement, by making at least three assumptions: unmeasured variables can be thought of as taking values; influences between these variables and others cannot spread faster than the speed of light; experimenters do have freedom to measure what they like without this changing the values that they would see if they make any particular choice. The conditions are usually called Realism, Locality and Freedom, respectively. The conclusion is that (if QM is true) nature is non-classical. It could then simply be that we must abandon realism (Bohr would say: "I  told you so"), but if you want to have realism -- it certainly has been an uncontroversial implicit or explicit feature of all physics for about 2000 years --  you have to abandon locality (this seems to have been Bell's inclination) or freedom (this is what Gerard 't Hooft seems to prefer).  Gill110951 11:07, 6 December 2006 (UTC)
thread_title: Quantum entanglement (bis)

message: The correct formula is ΔpΔx ≥ h-bar and where measurements are made once on each copy of an ensemble the formula is ΔpΔx ≥ h-bar/2. http://www.iisc.ernet.in/academy/resonance/Aug2004/pdf/Aug2004p46-56.pdf page 8 --Voyajer 16:28, 4 January 2006 (UTC)
thread_title: Any book that says ΔpΔx ≥ h is wrong

message: "The temperature at which all classical molecular motion stops, equal to 0 Kelvin or -273.15° Celsius. However, quantum mechanically, molecules cannot cease all motion (as this would violate the Heisenberg uncertainty principle), so at 0 K they still vibrate with a certain small but nonzero energy known as the zero-point energy." http://scienceworld.wolfram.com/physics/AbsoluteZero.html
Okay, this is another example where Heisenberg's microscope does not apply.  Is anyone measuring all the atoms in the universe at the same time so that a photon of light is hitting them so that they have an uncertainty of position and cannot reach absolute zero?
In other words, the Uncertainty Principle is applied to the universe even when no measurements are being taken.  Therefore, no disturbance is being made to the measurements.  The Uncertainty Principle is taken to be fundamental.  It says that fundamentally no moving particle can ever have an exact position.  Therefore, no moving particle can ever be said to stop its motion.  Therefore, no atom can cease motion at absolute zero.  This is without measurements being taken to "disturb" the particles.  Therefore, Heisenberg's microscope is wrong.
Now, I want to mention this caveat.  Heisenberg's Uncertainty Principle will in the near future be either proven or disproved.  In creating BECs (Bose-Einstein Condensate) scientists are building better and better instruments to reach absolute zero.  When they build one that reaches absolute zero, HUP will either be debunked or raised to the status of absolute law.--Voyajer 00:28, 4 January 2006 (UTC)
thread_title: Uncertainty Principle and Absolute Zero

message: Voyajer and company, I like the article I see. Congratulations to all of you. --Ancheta Wis 21:01, 8 January 2006 (UTC)
thread_title:  Positives 

message: Please also note I have listed the spectrum image for deletion for being Education license. (I don't see it justify FU either.) -- KTC 22:41, 8 January 2006 (UTC)
thread_title: Picture of spectrum has been put in for removal by

message: There appears to be strong opinion that the article is a fork. I am arguing that it is a completely separate article from Quantum Mechanics main article. --Voyajer 17:03, 9 January 2006 (UTC)
thread_title: It appears that in nominating the article it may be deleted

message: In the section on h-bar, there was a sentence comparing circles, which have 2 pi radians, with cycles "each having 180 degrees." I think originally it must have been intended to say that each half of a sine curve has 180 degrees. Anyway, I couldn't figure out exactly what was going on so I tried to rephrase it. Please put it back right if I misinterpreted something. P0M 06:59, 16 January 2006 (UTC)
thread_title:  Removed one phrase 

message: The text currently says:
:Bohr basically theorized that electrons can only inhabit certain orbits around the atom. These orbits could be derived even before the 1931 development of the electron microscope by looking at the spectral lines produced by atoms.
Is the electron microscope in any way relevant to knowledge about orbits of electrons? Unless there is some devious way that this works out, the above sentence will need to be removed.  P0M 18:09, 16 January 2006 (UTC)
thread_title:  Electron microscopes are not for examining electrons 

message: The text currently mentions "the magnetic moment of the orbital, which is a type of energy caused by the charge of the electron as it rotates around the nucleus." Energy is not caused.  Do you mean to speak of "force exerted"?  P0M 07:57, 20 January 2006 (UTC)
thread_title:  How can energy be caused? 

message: Will this work? Except that I should change "spectra" to "spectrum" and re-upload. P0M 01:34, 21 January 2006 (UTC)
thread_title:  images of line spectra 

message: I am happy to see "electromagnetic waves" so near the start.  In the Feynman Lectures, he brings up, at the start, that what one (the student) gains at the cost of complex wave functions and other difficulties is that the same principles now apply to "electrons and to light".  This not only motivates the student, it also automatically doubles (at least) his learning rate, because he is learning the same things about what he perviously thought were two different subjects.  David R. Ingham 06:29, 1 February 2006 (UTC)
replies: text: The change you created from electromagnetic_waves to waves had consequences that may be problematical. Did you intend to produce these changes in what the user would see when s/he clicks on the link? Please be careful. P0M 07:03, 1 February 2006 (UTC)

text: When you destroy one link and create a new link, please be sure that the new link goes somewhere useful. Did you try your new link yet? P0M 21:49, 1 February 2006 (UTC)

text: Anything--as long as it is not a smeared cat! ;-)  P0M 08:52, 2 February 2006 (UTC)
thread_title:  electromagnetic waves 

message: I think that is the wrong term for that other article.  The Born approximation article is mathematical.  How about "deeper" or "more technical".  I think "advanced" would also be too strong.  David R. Ingham 18:06, 1 February 2006 (UTC)
thread_title:  "mathematical" 

message: There is something wrong with this choice of words.  "Measured by"?  David R. Ingham 05:48, 2 February 2006 (UTC)
replies: text: The problem derives from anthropomorphizing a theory. How about, "Its widespread acceptance is due to its accurate prediction..."? P0M 09:05, 2 February 2006 (UTC)
replies: text: The two things are the same. It is a succes means it makes accurate predictions which means it is a success. String theory is not a success, even though it is very popular. The solution is to remove one of the repetitions. --MarSch 11:12, 2 May 2006 (UTC)
thread_title:  "Its success is due to its accurate prediction" 

message: There may be difficulties with general relativity, but does this belong in a discussion of the basics?  Are people reading this assumed to be versed in the subtleties of general relativity?  Should not they be told that it agrees with every test to at least the precision of usual floating point computer arithmetic first?  David R. Ingham 07:01, 2 February 2006 (UTC)
replies: text: I will await news from Voyajer about what he was really trying to say. I doubt he was referring to difficulties with general relativity, which would indeed be irrelevant here. Instead, I this maybe that vague sentence had something to do with places where relativistic factors have application to atomic scale events and the consequences for QM have not been worked out. P0M 09:17, 2 February 2006 (UTC)
thread_title:  "inconsistent with the consequences of other successful theories" 

message: One thing about which I disagreed with my thesis advisor was the historical approach in his text books.  I have later become more interested in the history of physics, but it seemed a bother to an enthusiastic student who wanted to know about nature and not about human history.
With the exception I wrote above, I think the history of light is fine.  But let us work towards having most of the history on one section and the rest pure physics.  That may be quite hard, but there is no schedule of budget to meet.  David R. Ingham 07:48, 2 February 2006 (UTC)
replies: text: IMHO there's too much history in this article.  For newbies to the subject the historical development is completely irrelevant and may actually hinder comprehension.  It should placed in an entirely separate article. --Michael C. Price talk 22:48, 15 October 2006 (UTC)
thread_title:  Old quantum theory, and so on. 

message: This may be OK, but the dark sensetivity of the eye is not so much less that one photon.  David R. Ingham 08:17, 2 February 2006 (UTC)
replies: text: We have a physiological reaction to the impact of light quanta. We "see" the burning match, however, not the photon. What would a photon look like? We have even less possibility of seeing a photon than we have of seeing an electron. If I have a camera with an ultra-fast shutter and very sensitive film I may be able to photograph a bullet from the side as it travels from a gun to a target, but that's because light strikes the bullet and gets reflected into my camera lense.  I can't shine light on a photon travelling from a laser pointer to a movie screen.  As far as our experience of photons goes, we are more like the shooter who pulls the trigger and then sees a hole appear in the target. P0M 09:43, 2 February 2006 (UTC)
thread_title:  "We cannot see photons" 

message: If the version called "mathematical" above does not have to introduce Fourier series, why do so here?  David R. Ingham 08:21, 2 February 2006 (UTC)
replies: text: I'm not sure of this, but I think it may have been an attempt to explain the prevalent use of h-bar (Dirak's constant) instead of h. To me it seems to be a mistake because both h and h-bar are conversion factors. The salient facts are that energy and frequency are proportional, and that they can only come in integer units. P0M 10:07, 2 February 2006 (UTC)
thread_title:  "Fourier series" 

message: I don't like introducing this statistical concept.  As far as I know, it is not really mathematics or statistical mechanics.  It is not a basic concept.  If it is really needed, how about speaking in terms of the Gaussian function and some simplified version of Fourier transforms (which I objected to above).  David R. Ingham 08:52, 2 February 2006 (UTC)
thread_title:  "standard deviation" 

message: One criticism I do not agree with is that this is "a 'fork' of the main article".  In school, qm is taught on many levels.  It is too complicated and too important to be covered, even in a fairly elementary way, in a single article.  I believe that some of the basic concepts, like a foreign language, are most easily absorbed at an early age.  David R. Ingham 17:53, 3 February 2006 (UTC)
thread_title:  Fork 

message: What would this article look like if we not only took the history part out but also avoided the seemingly mysterious h and h-bar? They are just conversion factors anyway. Has anybody actually figured out the wavelength corresponding to the lowest possible frequency? I suspect I've been indoctrinated by reading too many secondary sources that say that the energy of a photon has to be some multiple of h. That never seemed right to me. First, it does not seem to have any connection to experimental determinations of energies. Energies and frequencies are found, and then h is computed. Second, I can't think of any reason why there should be any limit on wavelength -- although there might be practical difficulties in creating or finding radiators beyond a certain length. ELF seems to have been detected down to a few hertz on earth, but Earth is a relatively small place. 
You mentioned Fourier expansions above. I don't think you can get rid of them so easily.  In Physics and Philosophy, p. 38f, Heisenberg says:
p. 38: “The precise mathematical formulation of quantum theory finally emerged from two different developments. The one started from Bohr’s principle of correspondence. One had to give up the concept of the electronic orbit but still had to maintain it in the limit of high quantum numbers, i.e., for the large orbits. In this latter case the emitted radiation, by means of its frequencies and intensities, gives a picture of the electronic orbit; it represents what the mathematicians call a Fourier expansion of the orbit. The idea suggested itself that one should write down the mechanical laws not as equations for the positions and velocities of the electrons but as equations for the frequencies and amplitudes of their Fourier expansion. Starting from such equations and changing them very little one could hope to come to relations for these quantities which correspond to the frequencies and intensities of the emitted radiation, even for the small orbits and the ground state of the atom. This plan could actually be carried out; in the summer of 1925 it led to a mathematical formalism called matrix mechanics or, more generally, quantum mechanics. The equations of motion in Newtonian mechanics were replaced by similar equations between matrices; it was a strange experience to find that many of the old results of Newtonian mechanics, like conservation of energy, etc., could be derived also in the new scheme.  Later the investigations of Born, Jordan and Dirac showed that the matrices representing position and momentum of the electron do not commute.  This latter fact demonstrated clearly the essential difference between quantum mechanics and classical mechanics.
If we are going to keep everything neat and consistent, shouldn't we go with the Dirak formulation that folds Heisenberg and Schrõdinger together? We would in any event need a clear example of matrix multiplication and how it can work out to be non-commutive. P0M 22:32, 4 February 2006 (UTC)
thread_title:  Spork 

message: I once had the privilege, with another physicist, of explaining quantum mechanics to a mathematician.  (We were working on radar but had time to talk.)  We started in the usual qualitative way that it is taught, in ordinary language, but he didn't seem to comprehend.  Then we started to remember how to express it in terms of Hilbert spaces, and it quickly became clear to him.  David R. Ingham 07:30, 3 February 2006 (UTC)
replies: text: I suspect that one of the reasons that this and similar articles are hard to formulate and hard to agree upon is that our verbal formulations of "wave" are tied too much to the everyday world.  Heisenberg, op. cit., p. 39, says that Schrödinger "succeeded in deriving the energy values of the stationary states of the hydrogen atom as 'Eigenvalues' of his wave equation and could give a more general prescription for transforming a given set of classical equations of motion into a corresponding wave equation in a space of many dimensions."  I have another mention somewhere, in one of Sears's physics texts I believe, that specifies that these waves are not in normal 3-D space. I think Sears uses the expression "configuration space." P0M 22:43, 4 February 2006 (UTC)
thread_title:  An unusual teaching experience 

message: I changed "mathematical".  (See above.)  That was a poor word to describe the quantum mechanics article, which suffers greatly from being written in ordinary language, rather than in linear algebra.
"Physical science" isn't right either.  It could be called a theory or a branch of physics.  Early in the 20th century, the word would surely have been "theory", but now qm is more like a "cornerstone" that underlies most of physics.  David R. Ingham 17:31, 3 February 2006 (UTC)
thread_title:  "physical science" 

message: Planck's Constant
"which predicted that radiation emitted by a heated object should theoretically be infinite, he started with a completely different basic premise: What if energy is not infinitely divisible?"
Coudn't the radiation emitted by heated object be infinite and the energy emitted be not infinitely divisible. There could be infinite packets of energy.
:The problem was to make a theory that would predict the correct, moderate, amount of radiant energy output. Maybe what you are complaining about is another instance of a kind of "solipcistic" account that seems to say that theory determines reality.  I'll check the remark you quoted in context.
Reduced Planck's constant
Error : "So, dividing h by 2 π describes a constant that, when multiplied by the frequency of a wave, gives the energy in joules per radian per second. And h/2 π is h-bar or \hbar = \frac{h}{2 \pi} \."
Unit of hbar is Joule second per radian and unit of \hbar multiplied by frequency is Joule per radian.
:Let's see. What is w/(y/z)? Isn't it wz/y?  The units for h should be Jouleˑsec,
h-bar = h Jouleˑsec/2π  = h Jouleˑsec/radian -- But isn't that = h Joule/(radian/sec)?  P0M 06:47, 21 February 2006 (UTC)
replies: text: Since the meaning is the same and the Jouleˑsec/radian formulation is a bit cleaner, I have changed that part. P0M 04:02, 23 February 2006 (UTC)
thread_title:  Doesn't make sense 

message: The writers who originally structured this section put things in what to me seems a strange order. The article has been essentially untouched for a long time while I have been researching some of the many problems left outstanding. Dipping back into the "full qm theory" section, it seems clear that it needs some structural changes. The primary problem seems to be how to insert the material about matrix math at the most appropriate point. Originally it was made to seem almost as though matrix math was some kind of geni who popped up to make truth out of the incomprehensible, so it got mentioned before it should have been. Bohr had things figured out. His math was correct, but apparently it went with directions for what had to be computed first and what had to be computed next. (Wish I had the original document.)  Then somebody saw how to express in in a relatively familiar, and mathematically "respectable" way, matrix mathematics.  Having a neat symbolism that helps you keep track of data and operations to be performed on that data may not make things as much more convenient as "self evident" than did the invention of zero, but it must have come close to that. P0M 00:47, 29 March 2006 (UTC)
replies: text: A month later I am much clearer on the matrix stuff. I've found enough early information to begin straightening this mess out. So much of the secondary material has been written on the basis of the writers' memories (or imaginations) that all sorts of misinformation has creapt in.  Many writers have tried to make things easier for the average reader by saying things that amount to "the number of beans in a can times the number of cans is not equal to the number of cans times the number of beans in a can," when in fact that are being multiplied are matrices, not integers. When I've got the math figured out (not easy when writers use their own symbols without defining them, assuming "they'll know what I mean"), I'll rewrite this section and provide good references. P0M 18:11, 7 May 2006 (UTC)
thread_title:  Full quantum mechanical theory 

message: original:
"However, strange and counter-intuitive this may seem, quantum mechanics however does tell us the location of the electron's orbital, its probability cloud."
I fixed some grammar and made it sound better into:
"How ever strange and counter-intuitive this may seem, quantum mechanics does still tell us the location of the electron's orbital, its probability cloud."
But it still sounds a little bit odd with the part after the second comma. I don't know enough of quantum mechanics to try to change it without changing the meanings. Maybe someone can, if they agree with me that it does sound off. Janechii 00:48, 7 May 2006 (UTC)
replies: text: It's got a couple of obvious problems" "How_ever" instead of "However," and a naked "this" (which the reader is free to fill out in whatever way his/her reading of the passages prior to it may suggest).  It doesn't help to have a "however...however..." construction either.  I'll try to intuit what the original writer meant and then try to fix it.P0M 17:49, 7 May 2006 (UTC)
replies: text: I think it had already been changed a little.  I fixed the "how ever", but (see above) the whole section needs to be rewritten so there is little point in fixing small problems. P0M 18:25, 7 May 2006 (UTC)
thread_title:  Odd Sentence? 

message: I'm puzzled as to why the sentence "All modern physical theories are quantum theories." was deemed to strong?--Michael C Price 21:34, 12 June 2006 (UTC)
replies: text: How about Chaos theory? Most physicist are working with QM, but not all. Zarniwoot 21:50, 12 June 2006 (UTC)

text: Usually, modern, as opposed to classical, includes the theory of relativity. I would say it depends on what is meant by "modern" and also by "fundamental". It may be diffecult to describe the importence of QM in one sentence. (I know I'm not helping here :( ) Zarniwoot 00:43, 13 June 2006 (UTC)
replies: text: The current version is: "all modern fundamental physical theories are quantum theories."  I am not sure where this "true of false" discussion originated; I guess I was tuned out at some crucial time period.  Anyway, I think the way it is now the average reader is likely to get a little confused or misled. I think maybe what needs to be made clear is that everybody is aware of the points at which quantum mechanical considerations come into play. How about: "All modern physics must appropriately reflect quantum mechanical interactions." When a "grand unified theory" is achieved there will be a clear connection between QM and everything else. On the other hand, if one restricts the scope of some division or field of physics narrowly enough there would be wide ranges of "QM-irrelevant" studies.  Doing so is arbitrary, of course. The instance mentioned above, "chaos theory," could be one such restrictive field where one could do lots of work and never touch a QM-sensitive interaction. On the other hand, an understanding of chaos theory is really the understanding of how a slight difference between two measurements can predict two greatly different outcomes at some time in the future, and marginal QM effects could produce one kind of such small variations.  P0M 05:02, 13 June 2006 (UTC)

text:  Good points all, but even chaos theory is based on classical mechanics, which we now know emerges from QM via Ehrenfest's theorem and the correspondence principle (shouldn't this be mentioned in the article, rather than just a reference?); in that sense therefore chaos theory based on quantum theory -- although many of its insights would be applicable even if classical mechanics were absolutely true.  --Michael C Price 11:39, 13 June 2006 (UTC)
replies: text:  If memory serves, "chaos theory" got its name because it was a discovery about the unexpected consequences of working out certain kinds of equations reiteratively that helped us to understand what appear to be chaotic phenomena.  So it is not a theory in the sense that thermodynamics is a theory. It's a kind of meta-theory in the sense that it explains not phenomena but the illusion of chaos in the working out of explanations of phenomena. The appearance of "chaos" may be a consequence of working out some equations associated with QM, but that's not quite the same as QM being the basis of chaos theory.  P0M 15:32, 13 June 2006 (UTC)

text:  I agree with all you've said, except the last half of the last sentence, which is just a disgrement about style, I think.  I'll reread the article and think about adding a ref' to the correspondence principle.... --Michael C Price 16:44, 13 June 2006 (UTC)

text: The term "physics theories" is conceptually a little slippery, no?  The question is whether we have a number of apparently competing theories that turn out to be either the same thing (i.e., one formulation can be converted into the other) or are linked at a more general level of organization, or whether there are two or more theories that are "modern" but unconnected. In The Elegant Universe,p. 3, Greene says: "As they are currently formulated, general relativity and quantum mechanics cannot both be right." The quest now is for a theory that will unite the two somehow, which will mean finding a more basic level of generality. When and if such a theory is successfully produced, it will have to account for the same things that QM does, just as QM has to account for all the things that classical physics predicts. P0M 17:25, 19 June 2006 (UTC)
thread_title:  All physics is quantum physics -- true or false 

message: This sidebar is, I believe, comprehensible only to people who already know what the writer was trying to convey. Would someone like to try to fix it up?  Here are some of the problems I see:
"Bohr's analysis of electron orbits as circular"
:The unsuspecting reader could guess either that Bohr analyzed the orbits of electrons and concluded that they are circular, or that Bohr assumed that the orbits are circular and attempted to draw theoretical consequences on that basis.
"A little math on circular orbits."
:It is a minor quibble, but the above collection of words is not a sentence. If you are Frank Lloyd Wright you can write that way. Mere mortals ought to stick to true sentences in deference to other mere mortals.
"Bohr was very familiar with the dynamics of simple circular orbits in an inverse square field as described in classical mechanics."
 
:At the bare minimum this sentence needs a wiki link to "inverse-square field". The average well-informed reader might even read this sentence as referring to a square field that is in some sense inverted.
"Simply explained: "
:This phrase gives a promise that is not needed and is not fulfilled.
"To find the acceleration of a circle, place it inside the shape of a square where tangents meet, then find the linear speed along one side of the square, then square the speed of one side to complete the speed of the entire square, then divide by the radius of the circle placed in the square to get the speed around the circle."
:Circles cannot accelerate. 
:What is the difference between putting a circle inside a square (by which I am guessing the author meant to say: construct a circle within a square) and putting a circle inside a shape? 
:"Where tangents meet" -- meet what?  It looks like the author is trying to describe a circle that has been fitted within a square so that it meets at four points -- no more and no less.  
:"Then find the linear speed ..."  The linear speed of what? Is the author trying to say that one should use the orbital speed of an electron travelling in the orbit diagrammed by the circle to calculate the speed of a point mathematically projected onto one side of the square?  
:"square the speed of one side"  The circle does not accelerate and the side does not move. If we are talking about the metaphorical speed of the shadow of an electron as it is projected on a wall perpendicular to the plane of the orbit, then it is clear that the speed of movement of that shadow will go from zero to some maximum and back to zero. So we are dealing with a function and not a constant when we talk about "the speed." 
:"then square the speed of one side to complete the speed of the entire square" -- Really? Going across the top of the square, the point has an average speed of 500 zonks/hour.  So going around all four sides of the square the point has an average speed of 2500 zonks/hour? What?!   
:"then divide by the radius of the circle ... to get the speed around the circle." Arggh. The author didn't mean for us to start with the "speed around the circle."  So what were we supposed to be starting with? And what does any of the above gobblydegook have to do with the following?  
The equation for the centripetal acceleration is a =v^2/r. That is, acceleration is inversely proportional to the radius of the circle. 
:Hmmm. We had something divided by the radius of the circle above. If we denote "the speed of one side" by s, then the "speed of the entire square", S = s2 / r.  Then in the following part the writer seems to equate "speed" with acceleration. 
If the radius is doubled, then the acceleration is halved.Also, Kepler's Third Law is that the radius cubed equals the circumference of the orbit squared. It immediately follows that the radius of any n orbit is proportional to the orbit n squared, and the speed in that orbit is proportional to 1/n. Speed times radius gives angular momentum. That leaves n-squared over n. It then follows that the angular momentum for any orbit n is just proportional to n. Bohr argued then that the angular momentum in any orbit n was nKh, where h is Planck's constant and K is some multiplying factor, the same for all the orbits, which was later determined to be 1/2\pi.
:Linear acceleration, a, is defined as the rate of change of velocity, and in orbital mechanics it isn't the speed of the orbiting object that changes, it is the velocity that changes -- or to put it in other words it is not the absolute value of the velocity that changes but its direction.  
:Let's either scrap this sidebar, scrap it and write a new one, or fix it so that a bright high school student interested in going into a physics major in university can see physics as a comprehensible activity. P0M 02:03, 22 July 2006 (UTC)
replies: text: I think you did right by deletion.  It was godawful mess.  --Michael C. Price talk 21:02, 22 July 2006 (UTC)
thread_title:  Sidebar in drastic need of a re-write 

message: From the article "Improving Student's Understanding of Quantum Mechanics" in the August 2006 Physics Today:
:A related false belief is that measurement of any physical observable causes the system to get "stuck" in the measured eigenstate forever unless an external perturbation is applied. Again, the statement is true only for observables whose operators commute with the Hamiltonian, but students seem to generalize that property of measurement to include all observables.
The old paragraph would seem to encourage this error.  David R. Ingham 21:12, 21 October 2006 (UTC)
thread_title:  An additional problem with the paragraph as it was 

message: I was thinking of taking (my altered version of) the paragraph out of the article until someone finds a more elementary way to address Wave function collapse, or perhaps better Measurement, but it does not look quite that bad to me as it now stands.  
What about summarizing how typical experiments are done on time dependent cases (such as scattering) and (nearly) time independent quantum systems (such as atomic and nuclear spectroscopy) and then mentioning that these approaches do not cover all cases?
David R. Ingham 22:48, 21 October 2006 (UTC)
thread_title:  What to do about it? 

message: If you have view on this please go to Wikipedia:Articles_for_deletion/Quantum_theory and cast your vote.  --Michael C. Price talk 06:02, 20 October 2006 (UTC)
replies: text: I.e. a content dispute, not a reason for an AfD.  --Michael C. Price talk 14:24, 22 October 2006 (UTC)
replies: text:  Perhaps it was rude of me to put it thay way.  No, it is not a reason for deletion, it is just a related subject.
I have said about all I have to say on this and trust that you and others will resolve the issues, if my perception that there were issue is correct.  It is really a matter or semantics and organization, which are not my strongest points.  David R. Ingham 19:36, 22 October 2006 (UTC)
replies: text: As AfD nominator you may withdraw the AfD.  --Michael C. Price talk 20:16, 22 October 2006 (UTC)
thread_title: AfD raised on [[Quantum theory]]

message: (Both 50 and 60 years seem too small to me.)  David R. Ingham 03:40, 22 October 2006 (UTC)
replies: text: I am assuming that this comment is irrelevant to the AFD.  The question of how long quantum physics has been important to consumer life seems to be what this comment was directed to.  The transistor has been around since sometime around 1948, so what earlier technological innovation do you have in mind? P0M 05:37, 22 October 2006 (UTC)
thread_title: History question