Why does decoherence not fully solve the measurement problem?

  • #101


Semiclassical here (regarding foundational QM) often refers to classical EM fields interacting with some quantum-mechanical particles. So it accounts for the wave-particle duality of the electron, but not for the particle duality of the photon.

The obvious first improvement of this model is called quantum electrodynamics (QED). This is obtained by quantising the EM field (thus accounting for creation and absorption of individual photons) and which basically results in perfect agreement with experiment (provided the number of electrons stays fixed).

In particular, semi-classical does not mean "little antennas with their radiation resistance". Such a model would be termed entirely classical, but it would be disparaged as ad-hoc (since, although one can perhaps come up with such a little classical model for any single experiment, you don't have a completely consistent a priori framework for modelling all experiments). Such a classical model even takes numerous results from standard QM as parameters (whilst standard QM obviously derives those itself from far fewer parameters), which contradicts justification for differing with standard QM.

Conway, since you seem reluctant to acknowledge photons, why don't you study the experiments that persuaded the community of their existence: Compton scattering (where photons bounce off a particle like ping-pong balls), the photoelectric effect (where some electrons accumulate escape-energy faster than could be explained by uniform irradiation, not to mention that if the light wavelength is lowered then electrons abruptly stop escaping regardless of energy availability), and single-photon sources (which have facilitated some elegant experiments in foundational QM, such as interference between photons emitted by different sources at different times)?
 
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  • #102


cesiumfrog said:
Semiclassical here (regarding foundational QM) often refers to classical EM fields interacting with some quantum-mechanical particles. So it accounts for the wave-particle duality of the electron, but not for the particle duality of the photon.

The obvious first improvement of this model is called quantum electrodynamics (QED). This is obtained by quantising the EM field (thus accounting for creation and absorption of individual photons) and which basically results in perfect agreement with experiment (provided the number of electrons stays fixed).

In particular, semi-classical does not mean "little antennas with their radiation resistance". Such a model would be termed entirely classical, but it would be disparaged as ad-hoc (since, although one can perhaps come up with such a little classical model for any single experiment, you don't have a completely consistent a priori framework for modelling all experiments). Such a classical model even takes numerous results from standard QM as parameters (whilst standard QM obviously derives those itself from far fewer parameters), which contradicts justification for differing with standard QM.

Conway, since you seem reluctant to acknowledge photons, why don't you study the experiments that persuaded the community of their existence: Compton scattering (where photons bounce off a particle like ping-pong balls), the photoelectric effect (where some electrons accumulate escape-energy faster than could be explained by uniform irradiation, not to mention that if the light wavelength is lowered then electrons abruptly stop escaping regardless of energy availability), and single-photon sources (which have facilitated some elegant experiments in foundational QM, such as interference between photons emitted by different sources at different times)?

Cesiumfrog, it's hard for me to know what to make of all this. A week ago I would have never believed that a group like Jaynes et. al. could be the universally acknowledged leaders of the "semi-classical school" without having dealt with my "little antennas with their radiation resistance". When SpectraCat steadfastly maintained this all last week, I could only marvel at what I considered his ignorance or willful blindness, especially when he insisted he knew all about "semi-classical treatments". How, I wondered, can he believe he knows what he's talking about if he's never even heard of calculating the radiation resistance of the hydrogen atom to get the Einstein A coefficient?

Cesiumfrog, I know I'm going to disappoint you because I sense that you feel you are being patient with me, trying to gently guide me back onto the right path by shaking of the blinders that prevent me from seeing the light. The sad fact is that what you have told me today only reinforces my conviction, my dementia as FrameDragger so ably diagnosed it, that I know things that nobody else does, that I'm on the track of something really big. Because if Jaynes et al weren't dealing in my little antennas, then maybe I'm the first. Maybe I have the answer to the big questions that have been puzzling the great thinkers for over a century...well, you see how the mind works.

What you probably can't imagine is how many different ways that I find support for my obsession. I don't want to provoke you but the fact is that I find several baffling contradictions, for lack of a better word, in your own arguments as presented in the four short paragraphs above; I'd like to try to explain them to you from my point of view, but I am almost sure that it would all end badly as it did with SpectraCat. You would take my attemps to explain my ideas as insufferable arrogance and gross disrespect for those who are obviously more knowledgeable than me.
 
  • #103


conway said:
Cesiumfrog, it's hard for me to know what to make of all this. A week ago I would have never believed that a group like Jaynes et. al. could be the universally acknowledged leaders of the "semi-classical school" without having dealt with my "little antennas with their radiation resistance". When SpectraCat steadfastly maintained this all last week, I could only marvel at what I considered his ignorance or willful blindness, especially when he insisted he knew all about "semi-classical treatments". How, I wondered, can he believe he knows what he's talking about if he's never even heard of calculating the radiation resistance of the hydrogen atom to get the Einstein A coefficient?

Cesiumfrog, I know I'm going to disappoint you because I sense that you feel you are being patient with me, trying to gently guide me back onto the right path by shaking of the blinders that prevent me from seeing the light. The sad fact is that what you have told me today only reinforces my conviction, my dementia as FrameDragger so ably diagnosed it, that I know things that nobody else does, that I'm on the track of something really big. Because if Jaynes et al weren't dealing in my little antennas, then maybe I'm the first. Maybe I have the answer to the big questions that have been puzzling the great thinkers for over a century...well, you see how the mind works.

What you probably can't imagine is how many different ways that I find support for my obsession. I don't want to provoke you but the fact is that I find several baffling contradictions, for lack of a better word, in your own arguments as presented in the four short paragraphs above; I'd like to try to explain them to you from my point of view, but I am almost sure that it would all end badly as it did with SpectraCat. You would take my attemps to explain my ideas as insufferable arrogance and gross disrespect for those who are obviously more knowledgeable than me.

Conway, I don't believe you're demented. I laid out a number of possiblities, of which "mental illness" is simply one, and not dementia. Given some time, I find you to be somewhat contradictory. When it comes to general physics, you seem utterly capable, able to give advice, etc. It may just be that this is the current limit of your understanding in the context of an internet forum.

If a trusted advisor, professor, rabbi, whatever... whom you presented your theory to carefully examined it, then laughed it off... how would you react? Your retreat into sarcasm and bitterness is understandable given the admittedly semi-hostile environment around you at this point. I wish that you would stop being defensive long enough to answer the questions posed to you by SpectraCat and Cesiumfrog, rather than beat a hastey retreat into the rhetoric of desperation.

Maybe you're just a crank, and I'm giving you too much credit (which would be odd, I'm not usually generous in that fashion), but I think this is a self-esteem issue for you, or some kind of article of faith. Maybe the issue is that you are unwilling to present your theory in the face of criticism and even scorn? If so, I would ask that you consider weathering the storm.

Personally, I think you want to get to point C from A without passing through B, and it pisses you off to have what you thought (think?) is a really elegant theory that still makes some kind of sense to you, blown away by literally EVERYONE you presented it to. That only leaves your ego (in the psychological sense, not the insult) very little room:

1.) You can admit that you're wrong, go back to the drawing board and resume at the point where you decided the learning was done, and it was time to become an amatuer theoretician. This is the healthy and normal response, albiet an unpleasant one

2.) You reject the faceless non-people who are just text on a screen to you after all, and stick to the principles and gumption that took you this far. Not a bad choice, but rigid, and therefore prone to rupture when you encounter more personal rejection

3.) We are all assholes who don't recognize your genius. Despite the professionals here believing otherwise, you are right in the face of all denial. What you formulated makes sense, following naturally from patterns you picked up during research and schooling for a career other than physics. This is very intuitive for you, and a joy ("obsession"), and who are we to piss all over it, right?

4.) Get lost in the numerology. "What you probably can't imagine is how many different ways that I find support for my obsession." I can believe it, much as I can believe that people see the Madonna in a pancake, or that we all see patterns because we're hardwired to find them (even when they are not there). People believe in god, a devil, angels, etc... your faith is hardly stranger. This is your religion, and we're not respecting that, much as you're not respecting that you came to a site, presented a theory, and upon rejection of it you now refuse to engage other than to defend your IMAGE.

It's always some variation on the old theme: MICE: "Money, Ideology, Compromise/Coercian, Ego". They'll make you betray confidences, change your life, and maybe end it... naturally they drive us to more subtle and less destructive ends. Ideology, and Ego for you conway, but not dementia. You're not stupid, or forgetful... you're excited like an addict chasing a high, and if you have to give up the notion of being "on to something big", then what's the point, right? Doesn't the knowledge that you're discovering something that eludes "great thinkers for over a century" excite and please you? It's like a secret garden, but sadly you made the error of turning over your fantasy to the cold embrace of the scientific method.

My advice? Find meaning, excitement, and purpose beyond "the next big thing". If that's what you think science is, and how most of physics is "done", you're in for some pain. Finally, if you're unwilling to engage someone as helpful and polite as cesiumfrog, why bother with any of this? What's the worst thing that could happen... Cesium rejects your hyothesis. The issue of "arrogance" was not your theory, but the manner in which you present it, as being on a par with QED and QFTs in general. I also seem to recall you kept telling Cat that something was "his theory" versus "your theory", when it was really "you vs. QM".

I suspect that if you don't actively attempt to piss off the people you present this theory to, you stand to learn something. Of course, to make this cicle complete, maybe you don't WANT that. Think about what you really want out of this... to crow about a theory you can't/won't share or adequately defend?
 
  • #104


conway said:
Cthuga, I appreciate your input, but I don't understand it, especially your use of the phrase "just the opposite". You say they compare the quantized two-level atom with a quantized cavity field mode (call this A) to the semiclassical model (B). Are you saying they compared A to B and found B could explain some but not all? That's what I understand...that A is SQM and B is "semiclassical".

If I've understood that correctly, that I have to ask again: just what was the "semi-classical model" they used if not my little antennas with their radiation resistance etc? I'd really like to know.

First: I did not read the entire thread, so I do not know what exactly is your understanding of semiclassical.

What Jaynes and Cummings did was: Take a two-level atom and treat it quantum mechanically. Now they studied the interaction of this quantum mechanical atom with classical light (semiclassical treatment) and a quantized cavity field mode (Jaynes-Cummings model, quantum treatment). So the difference is the treatment of the em field.

conway said:
Because if Jaynes et al weren't dealing in my little antennas, then maybe I'm the first.

Again, I have not read the whole thread and am not sure what exactly you are after. It is well known that a linear combination of energy eigenstates in QM can lead to an oscillating motion of charge and therefore an oscillating dipole. This is often explained in analogy to antennas in beginners' courses on em-theory or group theory because you can see that transitions are only dipole-allowed if they show a different symmetry. However, this model is not exhaustive. You need to go further to include quadrupole allowed transitions and need much, much more to explain nonclassical light from single photon sources.
 
  • #105


Okay, that's helpful, and it seems to agree with the way Cesiumfrog described the Jaynes school of thought. I thought all along what I was doing was the "semi-classical approach" but maybe I was wrong. I'm understanding that they use the e-m field as a perturbation, and then retreat to the SQM framework to calculate transition probabilities between eigenstates... the old Bohr "quantum leap". That's exactly halfway to my approach so I guess my ststem would have to be called the "75%-classical approach" because I treat the field as classcal e-m and the atom as a tiny oscillating dipole. So I don't have "transition probabilities" and quantum leaps, I have radiation resistance and continuous power output.

It's still hard for me to believe that no one has staked out this territory already. It seems pretty obvious. There's all kinds of phenomena that are totally natural in this system. I'd like to work though the physics with anyone who's interested but I'm having a problem getting people to take those "little antennas" seriously. People seem to agree that they exist theoretically but then insist that I'm not allowed to apply Maxwell's equations to them. When I do and get seemingly correct results (e.g. my ballpark calculation of the Einstein A coefiicient) it is dismissed as coincidence. Other people just want to psychoanalyze me. But then, you haven't asked me to rehash the old arguments from this thread. So let it be.

(EDIT): I hope this is not a further infraction, but I just wanted to clarify that my post was originally three paragraphs long and the last paragraph was deleted by the moderator.

(EDIT 2): There is just a little glitch in the notification system where by when I posted my first edit, it messed up the notification. The notification bar originally said: Edited by ZapperZ...Reaason: Removed advertisements for personal theory. Just wanted to clarify that it wasn't me editing my own post. (But this is.)
 
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  • #106
conway said:
Okay, that's helpful, and it seems to agree with the way Cesiumfrog described the Jaynes school of thought. I thought all along what I was doing was the "semi-classical approach" but maybe I was wrong. I'm understanding that they use the e-m field as a perturbation, and then retreat to the SQM framework to calculate transition probabilities between eigenstates... the old Bohr "quantum leap". That's exactly halfway to my approach so I guess my ststem would have to be called the "75%-classical approach" because I treat the field as classcal e-m and the atom as a tiny oscillating dipole. So I don't have "transition probabilities" and quantum leaps, I have radiation resistance and continuous power output.

It's still hard for me to believe that no one has staked out this territory already. It seems pretty obvious. There's all kinds of phenomena that are totally natural in this system. I'd like to work though the physics with anyone who's interested but I'm having a problem getting people to take those "little antennas" seriously. People seem to agree that they exist theoretically but then insist that I'm not allowed to apply Maxwell's equations to them. When I do and get seemingly correct results (e.g. my ballpark calculation of the Einstein A coefiicient) it is dismissed as coincidence. Other people just want to psychoanalyze me. But then, you haven't asked me to rehash the old arguments from this thread. So let it be.

(EDIT): I hope this is not a further infraction, but I just wanted to clarify that my post was originally three paragraphs long and the last paragraph was deleted by the moderator.

YOU'RE the guy with the blog about "quantum siphoniong"?! Oh hell, you should have said that to begin with so none us wasted our time. There is nothing even APPROACHING real physics in what you do, and I might add that NO ONE has agreed with your "little antennas".

Usually, whe people put a half-baked theory forth, they at LEAST try to understand the one they're trying to replace. How ridiculous, you're just another crank pushing your theory here, which is completely contrary to the educational mission of the site.

By the by, the original paragraph made it to my email notifications, so I was able to enjoy the full post. You know, I the first time you said it (a while back) I thought you were JOKING about the Nobel... this really is textbook illusory superiority, and Kruger-Dunning. Go back to school conway, and learn what the hell it is that science IS.

You seem to know some math, but your grasp of the sceintific method is breathtakingly poor. You are also quite deceptive:

https://www.physicsforums.com/showpost.php?p=2638960&postcount=32

Oh look, that's you claiming that the photographic process has been explained by this theory... one you came up with, and are trying to propogate. It's funny, you see, I wouldn't have referred to it as though I were simply one of many who believed this, and formulated it.
 
  • #107


Frame Dragger said:
YOU'RE the guy with the blog about "quantum siphoniong"?! Oh hell, you should have said that to begin with so none us wasted our time. There is nothing even APPROACHING real physics in what you do, and I might add that NO ONE has agreed with your "little antennas".

Usually, whe people put a half-baked theory forth, they...

I think I said they recognized the existence of the antennas in the model, they just dispute my claim that we should allow them to radiate according to Maxwell's equations. I hope I'm not taking any of these quotes out of context:

From Spectracat, post 85:

I assure you that I understand it just fine. I never said that the wavefunction was stationary ... I said that the expansion coefficients for the two basis states don't change in the absence of an external perturbation, which is not at all the same thing. Yes, there is a time dependent oscillation of the charge density in this picture. The oscillation will even also have a non-zero dipole component if you choose a single p-orbital for the expansion. However, as I said, in the absence of an external perturbation, such a superposition will persist forever with no change in the expansion coefficients for the eigenstates. This is basic stuff! ... It is a *classical* antenna, and it has no bearing on what an atom "actually does", at least not according to the well-established theory called quantum mechanics...

From collinsmark, post 69:

...my knowledge of quantum electrodynamics (above and beyond non-relativistic quantum mechanics) is presently rather sparse, but from what I can gather, I am not presently aware of electrons radiating energy when being in a superposition of states, even though the expectation value of the wave-function may oscillate.

From Cthuga, post 104:

It is well known that a linear combination of energy eigenstates in QM can lead to an oscillating motion of charge and therefore an oscillating dipole. This is often explained in analogy to antennas in beginners' courses on em-theory or group theory because you can see that transitions are only dipole-allowed if they show a different symmetry.

From yoda jedi, post 63:

RIGHT !
clever insight

called ψ-complete view, unlike ψ-epistemic.
as for ψ-epistemic which quantum states are solely representative of our knowledge.

Okay, that last one may be a little out of context.
 
  • #108


conway said:
I think I said they recognized the existence of the antennas in the model, they just dispute my claim that we should allow them to radiate according to Maxwell's equations. I hope I'm not taking any of these quotes out of context

Spectracat said:
post 85: "It is a *classical* antenna, and it has no bearing on what an atom "actually does", at least not according to the well-established theory called quantum mechanics...

Oh yeah, he's clearly agreeing with you there. :roll:
Really, I strongly suspect that Collinsmark, who just wanted to help you, Cthuga who just wanted to help you, are going to probably NOT wanting you to allign them with your farkakt guesswork masquerading as a theory.

As for Yoda Jedi, who knows, but since his quote IS out of context, I assume you put it in for bulk fiber? :smile:
 
  • #109


To set the record straight, I for one never agreed that the description of atoms in superposition states as classical antennas has any physical significance beyond understanding the dipole-selection rules (I think this is what Cthuga is saying as well). Furthermore I have stated in several places that I don't believe that the classical Maxwell equations can be used to extract physically sensible results from the oscillating charge densities predicted by the TDSE for an atomic superposition state.

To call something a "classical antenna" implies that it can absorb and emit radiation in a classical (i.e. continuous fashion), whereby the energy coupled into or out of the system is proportional to the squared amplitude of the electric field. It is well-known that this is not a correct description of absorption and emission from atomic states, therefore I would say that the description of atoms as "classical antennas" is physically incorrect.
 
  • #110


How did |conway> collapse into |[STRIKE]conway[/STRIKE]> :confused:
 
  • #111


Ahhhh, that sweet line through his name... it's like an icepick has been removed from my damned temple.

@Thread: Requiem in terra pacis. :smile: *wave*

EDIT: @Count Iblis: He was perturbed? :-p Orrr... maybe he was siphoned away by the staff... :-p
 
  • #112


Here is another example of the incorrectness of the antenna model: it doesn't give the correct explanation for superpositions of excited states. There is no physical reason why the ground state has to be used in a superposition ... if the gas is hot enough, then you should be able to observe superpositions of excited eigenstates as well.

Consider a two-state superposition of the 2s and 3p eigenstates. According to your classical antenna model, this should emit and absorb only at the lowest line in the Balmer series (i.e. the Hydrogen-alpha line at 656.3 nm). However, the quantum mechanical model I have described in past posts predicts that the emission will also occur at the Lyman-beta line (3p-->1s transition @ 102.5 nm), and in fact almost all of the emission will occur at that wavelength, since the Einstein coefficients for spontaneous emission are inversely proportional to the *third power* of the wavelength. Thus the Lyman-beta emission, which is absent from the "classical antenna" model for such a superposition, is ~260 times more likely than the Balmer-alpha emission.
 
  • #113


Count Iblis said:
How did |conway> collapse into |[STRIKE]conway[/STRIKE]> :confused:

As has been suspected for some time, conway was the return of someone twice-banned (now thrice-banned).
 
  • #114


George Jones said:
As has been suspected for some time, conway was the return of someone twice-banned (now thrice-banned).

Oh jeez ... what a waste of time all these threads have been. It explains a lot though .. I wonder what his handle will be the next time he raises his head? Perhaps "itrytoCONyouintothinkingmyWAY"? At least that would be more honest ...
 
  • #115


SpectraCat said:
Oh jeez ... what a waste of time all these threads have been.

I hope not a total waste of time; you have fleshed out some arguments that you might want to use in the future, and to which you can give links.
 
  • #116


George Jones said:
I hope not a total waste of time; you have fleshed out some arguments that you might want to use in the future, and to which you can give links.

Yes, you are right. What I really meant is that trying to convince him of anything was a waste of time ... keeping incorrect notions of how physics works out of a physics database is certainly not a waste of time.
 
  • #117


Frame Dragger said:
Ahhhh, that sweet line through his name... it's like an icepick has been removed from my damned temple.

You're killing me! :biggrin:

Hey, better you than me!
 
  • #118


SpectraCat said:
To set the record straight, I for one never agreed that the description of atoms in superposition states as classical antennas has any physical significance beyond understanding the dipole-selection rules (I think this is what Cthuga is saying as well).

Just for the records: Yes, that was my intention. I did not mean to suggest any far-reaching analogies between classical antennas and the emission behavior of atoms.
 
  • #119


All discussions pertaining to the running of PF and policies should be done in the Feedback forum, not in this or any other threads in the physics subforums.

Zz.
 
  • #120


DrChinese said:
You're killing me! :biggrin:

Hey, better you than me!

Thank you very much.

@SpectraCat: You don't strike me as a "cat" who falls for the same trick twice. :biggrin:

@ZapperZ: Noted. Seeing as you obviously read what I had to say on the subject, I can assume that I don't need to actually repeat it in that subforum?
 
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