please criticize my QM paper

[gib65]

Hello QM experts,

 

I've just written a paper on quantum mechanics, and I need some expert criticism. Basically, I want to know if I've got it right. Keep in mind it's written by a non-expert for non-experts.

 

The paper is written in three parts. The first part covers the basic facts of quantum mechanics, the second part covers the major interpretations in the field, and the third is my own personal take on these interpretations. Mostly, I need criticism on the first two parts. You can criticize the third part as well, but I'd appreciate if you kept your criticisms to an assessment of my understanding of the subject - not whether or not you agree with the positions I take (you can criticize my positions if you want, but that's not what I'm centrally concerned with).

 

I guess I should also say that this paper is part of a larger collection of papers that makes up my website. Right now, the QM paper is the only one up there, which means that a lot of the links don't work. This also means there might be some confusion over references to "my theory", so just FYI, the theme of the website is a philosophy of mine concerning the problem of consciousness (i.e. it's a theory of what consciousness is). Also note that I haven't tested it out in Mozilla (let me know if anything doesn't work in Mozilla).

 

Lastly, I hope it's acceptable posting a link to my website and asking people to visit it. I know this is sometimes taken as spamming or flogging, but I hope this can be taken as a special case since I'm asking for an evaluation on my understanding of quantum mechanics (consider it one enormous question that I had to create a whole new website in order to post it).

 

Anyway, here's the link: http://www.shahspace.com/mm-theory/qm/qm.htm

 

EDIT: I almost forgot to mention - I hope no one gets offended if I ask for sources in response to your comments. I know it seems contradictory to ask for criticism and then ask for proof once it's delivered, but on the internet, one never knows who the other person is. Anyone could post a criticism claiming to be an expert even though he/she is just some dilettante crackpot who thinks they know it all. I wouldn't know them from the real experts, so if I don't know who you are or if your comments seem suspicious, I might ask for sources. So don't take it as confrontational, it's just that I want to be sure I'm getting the goods.

[timo]

Disclaimer: I am absolutely not a QM-expert. I've tried reading your text but stopped after about 1/4th of the text because it became too time-consuming. Here's my notes from reading:

 

- Your homepage does not diplay properly on a screen resolution 1024x768.

- You are saying "it's written by a non-expert for non-experts" but on your HP you say "there are two papers in this website that the reader will not get through without a thorough understanding of quantum mechanics". Sounds like some contradiction to me.

- Can't comment on the historical statements.

- Style: Don't sound so dramatic, e.g. "in which we find principles of such counterintuitive caliber that it shakes the foundations of even a layman's understanding of how the everyday world works".

- Explicitely not mentioning what a "mode" is leads to the information content of the whole "quantized energy" section to be zero (at least I didn't understand it).

- Chosing an appropriate f and natural n, I can still get any amount of energy E=nhf. Unless there is some reason that fixes f or n, E=nhf does not quantize energy.

- Mayhaps the high energy photon in the animated picture shouldn't be emitted (especially not in the direction of the outgoing electron). Picture seems pretty nice otherwise (perhaps a bit too fast).

- Too much text about the prism, imho. E.g.: does it really matter that for some materials the refraction index decreases with wavelength while it dies increase for others?

- 2nd animated picture doesn't show me anything. Giving explanations to your pictures would generally be a good idea (even if it's just by making the picture clickable and link to a different page which contains the picture and an explanation).

- Orbital. Just like "mode", except now you even have an unexplained picture using the term.

- "What an orbital is is not important for this discussion, except to say that they are regions of space local to the nucleus of an atom where electrons are confined to, and that their shapes come in different forms and sizes." -> I don't understand that sentence, but it sounds wrong.

- Mayhaps try avoiding the term "anomaly". In physics, that term is usually used for some (context-dependent) very specific effect/meaning while you just seem to mean "unexpected behaviour" or something like that.

- I am not sure that a big-bang model was widely accepted at the time atomic spectra were explained.

- Not explaining orbitals => no fix on f => no quantization of energy => you didn't really show why atoms are stable. Or in other words, the answer to "The reader can see how useful the quantization of energy really was to the scientific community" is "no, they can't".

 

From here on, I switched reading mode to "skimming":

- "When the amplitude doubles, the light becomes twice as bright." I am not exactly sure how brightness is defined (probably something like "log(|A|²)" but you might want to look it up yourself), but I think that statement is wrong.

- "the larger the object, the more narrow the region this wave covers,". Ok, you didn't explain what a wave is so there is some interpretational degree of freedom. But it's misleading, at least. For me, a baseball almost always has a wave function that is more widely spread out around the position than that of an electron (due to the internal structure).

- Superposition is not unqiue to QM. You have superposition of gravitational fields in Newtonian gravity, superposition of electrical fields in electrostatics, ... .

 

I stopped reading at this point; it became too time-consuming for me and I understood little. Some general comments:

 

- You seem to stop with explaining exactly at the points where things start to become interesting. I assume it has to do with your knowledge stopping at this point.

-- Then, saying "it's not important what this is exactly" is a bit dishonest. How do you know whether it is important or not?

-- As soon as you say "let's skip that for now", you could make some note that this is a starting point for yourself where you could deepen your own understanding.

 

- You seem to put relatively little information into a lot of words. You might want to think about compressing the text a bit to have a better information/word ratio. This is just my personal opinion and style preference, others -especially the potential reader of your text- might have other preferences.

 

Enough for now, I think.

 

EDIT: No problem if you ask for references, but don't be offended if I don't spend my time doing research if I don't immediately know some example or reference of my head.

[gib65]

Disclaimer: I am absolutely not a QM-expert. I've tried reading your text but stopped after about 1/4th of the text because it became too time-consuming.

 

At least you read some of it. I owe you for that.

 

Thanks for the comments. I'll respond to a few of them. Those that I don't respond to I'm just taking as they are.

 

- You are saying "it's written by a non-expert for non-experts" but on your HP you say "there are two papers in this website that the reader will not get through without a thorough understanding of quantum mechanics". Sounds like some contradiction to me.

 

Maybe I should replace the word "thorough" with "rough".

 

- Explicitely not mentioning what a "mode" is leads to the information content of the whole "quantized energy" section to be zero (at least I didn't understand it).

.

.

.

- Orbital. Just like "mode"' date=' except now you even have an unexplained picture using the term.

[/quote']

 

This is a difficult thing for me. It's *partly* because my understanding of these concepts (modes and orbitals) don't stretch much beyond what I've written, but I suppose I could elaborate on it. Alternatively, I could simply drop any mention of modes or orbitals all together. On the section for orbitals, I could simply say "The reason why the pattern is unique for each element has to do with the unique structure of the atoms composing each element." and leave it at that. As for "modes", I could just say that the formula that lead to the ultraviolet catastrophe calculated the energy (not modes) of radiation at a specific frequency. This is one way I've heard the problem put, but I'm not sure if this is fully accurate (and I wondering if it matters). I have to strike a balance between thoroughness and brevity. I don't want this paper to be too long since it's only meant to be a brief rundown of quantum mechanics, but I don't want my readers to be lost in the wake either. Maybe what I should do is add a paragraph near the beginning stating that this overview is brief and may contain too much information in too little space - maybe provide some links for more in-depth reading on the subject.

 

- Chosing an appropriate f and natural n' date=' I can still get any amount of energy E=nhf. Unless there is some reason that fixes f or n, E=nhf does not quantize energy.

[/quote']

 

n is fixed to the positive non-zero integers. That's the whole gist of Planck's hypothesis. He didn't give a reason. Einstein did though: energy comes in fundamental/indivisible particles called "photons".

 

- Mayhaps the high energy photon in the animated picture shouldn't be emitted (especially not in the direction of the outgoing electron). Picture seems pretty nice otherwise (perhaps a bit too fast).

 

As in' date=' get rid of the photon once the electron is knocked out of its orbit? That might actually be better.

 

- I am not sure that a big-bang model was widely accepted at the time atomic spectra were explained.

 

So get rid of "shortly after the Big Bang"?

 

- Not explaining orbitals => no fix on f => no quantization of energy => you didn't really show why atoms are stable. Or in other words' date=' the answer to "The reader can see how useful the quantization of energy really was to the scientific community" is "no, they can't".

[/quote']

 

I hope that after making the above fixes, it becomes more clear.

 

- "When the amplitude doubles' date=' the light becomes twice as bright." I am not exactly sure how brightness is defined (probably something like "log(|A|²)" but you might want to look it up yourself), but I think that statement is wrong.

[/quote']

 

You know what, I think you're right. I vaguely remember reading somewhere that the intensity/brightness of the light quadruples with the doubling of the amplitude. I'll have to look that up.

 

- "the larger the object' date=' the more narrow the region this wave covers,". Ok, you didn't explain what a wave is so there is some interpretational degree of freedom. But it's misleading, at least. For me, a baseball almost always has a wave function that is more widely spread out around the position than that of an electron (due to the internal structure).

[/quote']

 

By "internal structure", do you mean the fact that the baseball is bigger, and therefore its wave must span at least the width of the baseball which is so much wider than the width of an electron? What if I said "the larger the object, the more narrow, in proportion to the size of the object, the region this wave covers" or something like that?

 

- Superposition is not unqiue to QM. You have superposition of gravitational fields in Newtonian gravity' date=' superposition of electrical fields in electrostatics, ... .

[/quote']

 

Would it be better if I said superposition of position, momentum, spin, etc. is unique to quantum mechanics?

 

I stopped reading at this point; it became too time-consuming for me and I understood little. Some general comments:

 

I appreciate the reading you did do.

 

You seem to put relatively little information into a lot of words.

 

My feeling is that I'm trying to cram too much information into too few words, and some of that information is getting lost. I think it might come across as too little information because of this loss, and too many words because the lost information resides in those extra words.

 

But I do appreciate your comments, and I take most of them to heart.

 

One thing I might note: as it stands right now, most of the links don't work. That includes some of the icons in the left margin, but not all. I have these links in the left margin at key points where I feel a ton more could be said on the subject. For example, where I talk about orbitals, I have a link to the left that takes you to the wikipedia article on orbitals. The link works on my end. Mabye it doesn't for you (if not, would you please let me know?) I'm hoping this helps alleviate the difficulties with information not being clear as the reader can click on these links for further information.

[timo]

n is fixed to the positive non-zero integers. That's the whole gist of Planck's hypothesis. He didn't give a reason. Einstein did though: energy comes in fundamental/indivisible particles called "photons".

My point was a little more sophisticated. Even if you fix n=1, you can still get any energy E from E=nhf=hf, by chosing f = E/h. The point is, that you need some mechanism/reason why f is not arbitrary. Actually, the reason is that f is fixed by the mode or the change of orbital. Or possibly easier: f is fixed by the wavelengths of the light. So you cannot say that light could only carry energy in discrete packages (because I can mix frequencies f to make it fit), but you can e.g. say that light with a wavelength of 600 nm can only carry discrete amounts (because you fixed the frequency with the wavelength). I'm not sure if the fixation of the frequency, its importance and the reason why it is fixed is obvious to you or not. But you didn't seem to stress the point sufficiently (I might have overread it, also).

 

 

 

So get rid of "shortly after the Big Bang"?

Depends. I am a physicist, not a historian. So I cannot check any of your historical claims without reading up on it. The big bang notion just looked particularly strange to me. Keep it in if you can verify that it's true. Kick it out if you can't.

EDIT: Just remembered the context. From the message you want to get across: It doesn't really matter if the atoms radiate off shortly after the big bang or shortly after now (like "within the next few minutes" - but you'd better look up the actual time predicted). In fact, "shortly after now" is a much more understandable statement, because you can imagine the enviroment better.

 

 

By "internal structure", do you mean the fact that the baseball is bigger, and therefore its wave must span at least the width of the baseball which is so much wider than the width of an electron?

Yes.

 

What if I said "the larger the object, the more narrow, in proportion to the size of the object, the region this wave covers" or something like that?

From the (in)famous uncertainty relation of position and momentum, the localization in space seems to be largly governed by the uncertainty in momentum. A realistic statement would be that for a baseball, the uncertainty in position (and momentum) is practically negligible (try calculating the uncertainty in momentum if the uncertainty in position was 1 nm).

 

 

Would it be better if I said superposition of position, momentum, spin, etc. is unique to quantum mechanics?

No, not really. I wouldn't even know what that means.

 

 

My feeling is that I'm trying to cram too much information into too few words, and some of that information is getting lost. I think it might come across as too little information because of this loss, and too many words because the lost information resides in those extra words.

It's really just my personal impression. Others might see that differently.

 

 

One thing I might note: as it stands right now, most of the links don't work. That includes some of the icons in the left margin, but not all. I have these links in the left margin at key points where I feel a ton more could be said on the subject. [...] The link works on my end. Mabye it doesn't for you (if not, would you please let me know?).

I did not even realize the links when I read it. They work.

[gib65]

My point was a little more sophisticated. Even if you fix n=1, you can still get any energy E from E=nhf=hf, by chosing f = E/h. The point is, that you need some mechanism/reason why f is not arbitrary. Actually, the reason is that f is fixed by the mode or the change of orbital. Or possibly easier: f is fixed by the wavelengths of the light. So you cannot say that light could only carry energy in discrete packages (because I can mix frequencies f to make it fit), but you can e.g. say that light with a wavelength of 600 nm can only carry discrete amounts (because you fixed the frequency with the wavelength). I'm not sure if the fixation of the frequency, its importance and the reason why it is fixed is obvious to you or not. But you didn't seem to stress the point sufficiently (I might have overread it, also).

 

I'm not 100% familiar with modes or changes in orbitals, but you did make me think about the absolute velocity of light (which pretty much fixes frequency for a given observer). I would either need to mention this (which brings in whole new ball of wax vis-a-vis relativity) or talk about wavelength as you said.