Classical Atom Models: A Nobel Prize Waiting to be Won?

[ZapperZ]

Ah, it always useful to fish, that is the only way to learn ! But it is exactly Laughlin who provided at the same time this classical picture ! I assume that what you mean by first principles is that Tinkham describes an *effective* field theory based upon symmetry principles and some other simplifying assumptions ? It is long ago that I did solid state physics : so you might wish to explain us what is *essentially* quantum in the effect of superconductivity. To start with, what quantum ingredients are used??

Sorry, no go. One only needs to look at the starting point of the BCS theory, and they're everywhere. You were the one who claimed there are "classical" ingredients to this. Yet, you CLEARLY are refusing to provide evidence to back it up. Please show me exactly where in the BCS theory is the "classical assumption" made.

And while you're at it, please show where in Laughlin's PRL paper on FQH did he "provide" the classical picture.

Zz.

 

[Careful]

Sorry, no go. One only needs to look at the starting point of the BCS theory, and they're everywhere. You were the one who claimed there are "classical" ingredients to this. Yet, you CLEARLY are refusing to provide evidence to back it up. Please show me exactly where in the BCS theory is the "classical assumption" made.
And while you're at it, please show where in Laughlin's PRL paper on FQH did he "provide" the classical picture.
Zz.

Really, could you enlighten then this poor mind which does not see ?? This is just a friendly question ; until now in our conversations you have only said no no and I have often backed my claims up with concrete references and reasons saying yes yes - this has happened many times also with other PF mentors. Now, this is clearly your field of expertise (I am just a poor GR kid) so you should radiate on the classical GR world here, I am all ears. All I said moreover is that I do not see anything exclusively quantum in the possibility of Cooper pairs; so I would really welcome your insight in WHY it is so, perhaps you could erase my blindness ? I will cite you from the laughlin reference:

**Laughlin discovered a useful and beautiful analogy between the interacting electrons of the fractional quantum Hall effect and a one component classical plasma of particles interacting with a logartihmic potential ... ** I said there was a analogy known up to a certain level; I did not claim more.

So, I think this should be a definite ``yes go´´. It is easy to have criticisms on every attempt when you rocksolidly stick to what you know best. It would be much easier for me not to look for anything else ! So perhaps we can turn this into a constructive discussion.

 

[ZapperZ]

Really, could you enlighten then this poor mind which does not see ?? This is just a friendly question ; until now in our conversations you have only said no no and I have often backed my claims up with concrete references and reasons saying yes yes - this has happened many times also with other PF mentors. Now, this is clearly your field of expertise (I am just a poor GR kid) so you should radiate on the classical GR world here, I am all ears. All I said moreover is that I do not see anything exclusively quantum in the possibility of Cooper pairs; so I would really welcome your insight in WHY it is so, perhaps you could erase my blindness ? I will cite you from the laughlin reference:
**Laughlin discovered a useful and beautiful analogy between the interacting electrons of the fractional quantum Hall effect and a one component classical plasma of particles interacting with a logartihmic potential ... ** I said there was a analogy known up to a certain level; I did not claim more.
So, I think this should be a definite ``yes go´´. It is easy to have criticisms on every attempt when you rocksolidly stick to what you know best. It would be much easier for me not to look for anything else ! So perhaps we can turn this into a constructive discussion.

Sorry, but you call this a "constructive discussion"?

You made an off-the-cuff remark that BCS theory had a classical component. When I question you to show specifically where this is, you cite poor memory. I find it incredulous that you would use that as an excuse, yet you make no qualms in making a statement about BCS theory. So where is your "concrete references" now?

I have no desire to tell you about BCS theory when this is one of the, if not the, most well-publicized theory of all time. The BCS Hamiltonian is known to everyone who would even look at a Superconductivity text. This thing is well established. What is NOT well-established is what you claim. When someone is making non-standard claim about an established principle, shouldn't the responsibility falls on that someone who produce the evidence and NOT the other way around?

And since WHEN do we do physics simply by citing quotes. I cited Carver Mead not just for his quotes, but because I understand intimately the subject matter he was discussing and not just superfically the statements he made. I asked you to look at the Laughlin's PRL paper and show me where he actually did anything "semi classical" to derive his wavefunction for FQHE. Again, you could not produce such a thing.

And you wanted a constructive discussion? Oy vey!

Zz.

 

[Careful]

There are pleanty of people around here asking about well established physics and they get a perfectly good aswer. So, why should I be treated differently ??


** You made an off-the-cuff remark that BCS theory had a classical component. When I question you to show specifically where this is, you cite poor memory. **

I did not make such claim, I said I saw no reason why Cooper pairs could not be formed by a classical principle. I am asking you here for your insights why this should not be so and also for your expertise what is so quantum about superconductivity.

Can you provide me with an internet reference where I can find a DERIVATION of BCS Hamiltonian from the physical lattice structure and the detailed interactions ?? Looking at the Hamiltonian only tells me that Cooperpairs are put in by hand. I am just interested in this, that's all.


**
And since WHEN do we do physics simply by citing quotes. **

So what is wrong with this quote which you can find in the nobel lecture. If I misunderstood what is meant, I am sure you can clarify it. Moreover, it is your responsability to explain to what degree this well established theory is derived from first principles and giving the effective Hamiltonian does not explain anything unless you provide a reference which shows this Hamiltonian is reasonable.

 

[member 11137]

Can you provide me with an internet reference where I can find a DERIVATION of BCS Hamiltonian from the physical lattice structure and the detailed interactions ?? Looking at the Hamiltonian only tells me that Cooperpairs are put in by hand. I am just interested in this, that's all.
**
And since WHEN do we do physics simply by citing quotes. **
So what is wrong with this quote which you can find in the nobel lecture. If I misunderstood what is meant, I am sure you can clarify it. Moreover, it is your responsability to explain to what degree this well established theory is derived from first principles and giving the effective Hamiltonian does not explain anything unless you provide a reference which shows this Hamiltonian is reasonable.

Hey people: not enougth war on the Earth ? Carefull, I am not a specialist and not a mentor of this website. I also don't know your level and if it can help you, but did you try at the following adress ?
http://ocw.mit.edu/index.html
I have found an interesting lecture on the BCS (perhaps only a special case and to easy for you; I don't know; sorry)

 

[Careful]

Hey people: not enougth war on the Earth ? Carefull, I am not a specialist and not a mentor of this website. I also don't know your level and if it can help you, but did you try at the following adress ?
http://ocw.mit.edu/index.html
I have found an interesting lecture on the BCS (perhaps only a special case and to easy for you; I don't know; sorry)

Hi, thanks, will take a look later on. What I am interested in is a derivation of an effective field theory of Cooper pairs from an exact lattice field theory (starting from known interactions). Screening on the web, I bumped upon the following reference:
cond-mat/0006097 where the authors claim to have done this in a perturbative approach for the TWO dimensional, Euclidean, two component Ginzburg-Landau model. I am not a condense matter physicist, so I wonder wether ZapperZ knows if more progress is made in this direction (in 3+1 dimensions for example). The point I was trying to make here, is that you still have to DERIVE the Cooper pair mechanism from first principles before you can claim that QM *predicts* superconductivity *from first principles*. I do not dispute that the idea of Cooper pairs and the associated BCS Hamiltonian do a good job, but that is not sufficient. But I can be wrong here, and just be ignorant of more significant progress. That is why I ask an expert like ZapperZ.

Cheers,

Dr. Careful

 

[reilly]

I largely disagree with one statement which repeatedly is made by QM proponents. IF one would come up with a consistent CM scheme which explains all experimental outcome which is also fitted by QM, THEN the CM theory is BY FAR preferred from the ontological point of view. We would dispose at that moment of a single unifying ontology, it is shocking to see how few of you are not aware of/``in for´´ this argument.

Well, Careful, when that great CM theory arrives, then we'll worry about ontological nicieties. To me it's shocking that anyone would would be shocked about hypotheticals, even within the arcanities of QM. How in the world, do you do all of chemistry and atomic physics, including emission and absorbtion spectra, and QED to some 13 decimal places, without QM? Curious minds want details, physics, not speculative philosophy. How do you go about producing this theory of the future?

Regards,
Reilly Atkinson

 

[Sherlock]

It seems to me that the main problem for a CM description of quantum phenomena is that we can't see the media in which quantum disturbances are occurring in nature. In order to say anything at all about quantum phenomena, they have to be amplified (sometimes through several, ingeniously designed, steps) to scales which are amenable to our sensory perception. This doesn't mean from spatially small to large necessarily. It means from disturbances in an undetectable medium (or media) to disturbances in detectable media. So, I'm thinking of the necessary transformations to observable phenomena as going through energy scales. Is this an ok way of looking at it? Is there a better way?

In this way of looking at the problem, there doesn't seem to be a theoretical solution to the problem of rendering the nature of quantum phenomena more amenable to a description in terms of analogs from our sensory experience of nature than it already is. Given more sensitive instruments and even more ingenious detection schemes, it seems that as (rather, if) quantum phenomena become more amenable to CM descriptions, then those descriptions will be adopted. But, for now, they are rendered as classically as is possible it seems.

 

[Careful]

Well, Careful, when that great CM theory arrives, then we'll worry about ontological nicieties. To me it's shocking that anyone would would be shocked about hypotheticals, even within the arcanities of QM. How in the world, do you do all of chemistry and atomic physics, including emission and absorbtion spectra, and QED to some 13 decimal places, without QM? Curious minds want details, physics, not speculative philosophy. How do you go about producing this theory of the future?
Regards,
Reilly Atkinson

You seem to have missed that my statement was a reaction on the assertion that a CM theory of microphenomena is only worthwhile when (a) a future experiment falsifies QM (b) when it gives easily rise to new predictions. Oh for sure I want details, and SED and the self field approach are far from speculations; they are useful first rigorous steps in my opinion. I seems to me that when the scientific community wants to invest millions of dollars into ``constructs´´ such as string theory, supersymmetry, LQG and so on, which do not have even produced a single experimental prediction in 30 years (supersymmetry is still waiting for falsification and LQG is still digesting the Hamiltonian constraint); then for sure one might give CM a good try. Since you are such a curious mind, why don't you tell me where QFT derives an effective theory of cooperpairs from first principles ??

 

[DrChinese]

I seems to me that when the scientific community wants to invest millions of dollars into ``constructs´´ such as string theory, supersymmetry, LQG and so on, which do not have even produced a single experimental prediction in 30 years (supersymmetry is still waiting for falsification and LQG is still digesting the Hamiltonian constraint);

There is a difference, as you should know. Supersymmetry promises a unified theory, which is a specific benefit. CM promises absolutely nothing, and I do mean nothing as in nada and zilch; and it is completely ridiculous to claim otherwise. Why should anyone invest a penny in it? There is only one reason, and that is BLIND FAITH.

Of course, the search for a TOE may not lead to anything anyway, as perhaps there is no unification of GR and QFT.

 

[Careful]

**There is a difference, as you should know. Supersymmetry promises a unified theory, which is a specific benefit. **

that is funny: supersymmetry is one component in the fabric of superstringtheory and has already been the subject of experiments for 30 years now with constant falsification of the specific claims made (concerning the energy scales at which supersymmetric partners ought to be found; the same game - to some lesser extent- concerns the Higgs boson btw ). By the way, as you should know, EXACT supersymmetry HAS to be broken in our universe (anthropic principle) If you do not mind this, then I do not understand why you are so protective concerning Bell experiments which are not conclusive at all


** CM promises absolutely nothing, and I do mean nothing as in nada and zilch; and it is completely ridiculous to claim otherwise. Why should anyone invest a penny in it? There is only one reason, and that is BLIND FAITH. **

Blind faith is the guideline of the above mentioned programs too. And I think any CM'mer would agree that we take a leap in the dark; but that is fine, that is what scientific exploration is about. The point which was already made for a LONG time by Vanesch is that it is just a matter of taste wether you start from GR or QM. The latter is done consistently for some 40 years now, and apart form toy models in lower dimensions the program really got nowhere. It seems to me that you are too much impressed by merchandising tricks ...


**
Of course, the search for a TOE may not lead to anything anyway, as perhaps there is no unification of GR and QFT**

So, why not try CM: if CM gets the necessary part of QM out, we are done. By the way, I am still hoping you can - as a quantum erudite - give me a reference for the above question concerning cooper pair formation.

 

[vanesch]

I seems to me that when the scientific community wants to invest millions of dollars into ``constructs´´ such as string theory, supersymmetry, LQG and so on, which do not have even produced a single experimental prediction in 30 years (supersymmetry is still waiting for falsification and LQG is still digesting the Hamiltonian constraint); then for sure one might give CM a good try.

As I said already, LQG approaches and so on (brilliant or misguided as they may be) have the conservative advantage that they AUTOMATICALLY reduce to quantum theory in "lesser" areas. So they have their "correspondence principle" build into them and as such do not have to justify themselves comparing to EXISTING EXPERIMENTAL RESULTS. So they are already *beyond* the status of where you are: they *already acquired* agreement with existing experimental results, while you are saying that one day you HOPE to acquire agreement with existing experimental results.

Now, let us, for the sake of argument, follow your reasoning. Let us suppose that the "true" theory of nature is a CM theory, and that by some very bizarre circumstances, in the 20ies, people took a wrong turn, and discovered a very strange theory - completely wrong - but that spits out results in agreement with experiment for about everything that it is confronted with, until they finally, one century later, hit the wall of this sideroad. How do we know that we hit a wall ? The only way to know for sure is by experimental falsification! At that point, you WILL find people ready to fund such searches, and moreover, they will be guided by experiment. So why spend money on it before ?

And let us now, for sake of argument, suppose that the theory you are looking for doesn't exist. Now, suppose that you get it your way, and that a lot of people are paid to look for it. They find lots of partial results, which can agree with QM results and experiment in certain areas, but not with others. How do you finally know that you are hitting a wall ?

 

[Careful]

**As I said already, LQG approaches and so on (brilliant or misguided as they may be) have the conservative advantage that they AUTOMATICALLY reduce to quantum theory in "lesser" areas. So they have their "correspondence principle" build into them and as such do not have to justify themselves comparing to EXISTING EXPERIMENTAL RESULTS. So they are already *beyond* the status of where you are: they *already acquired* agreement with existing experimental results, while you are saying that one day you HOPE to acquire agreement with existing experimental results. **

Ah but they sacrifice locality and by far do not know anything yet about the low energy limit of their hypothetical (read: does not exist yet) theory (apart from some imaginary wishful ansatze).
So, it is NOT true that they fit with current experimental GR results at this moment in time (remember that taking the classical limit of a quantum theory requires FULL knowledge of the theory and is a very subtle issue).
Like I said, it is just what you wish to consider; I save the GR output and locality and sacrifice QM for now. In my view this is equivalent.


The conclusion from the rest you write is : ```we have no clue whatsoever, but we wish to remain conservative´´. My answer is : that is not how science progresses, certainly when other reasonable alternatives are available.

 

[vanesch]

Ah but they sacrifice locality and by far do not know anything yet about the low energy limit of their hypothetical (read: does not exist yet) theory (apart from some imaginary wishful ansatze).

I think that your arguments are less arguments for supporting your programme than for diminishing funding for these programmes - something I wouldn't mind much, honestly. And if you listen carefully, you hear these arguments more and more.

 

[vanesch]

The conclusion from the rest you write is : ```we have no clue whatsoever, but we wish to remain conservative´´. My answer is : that is not how science progresses, certainly when other reasonable alternatives are available.

Science progresses by experimental falsification. If it ain't broken, don't fix it. You can call that "conservative" if you wish. All the discussion is about how reasonable your alternative is. You find it reasonable, but people deciding about funding apparently not. They take the bets, that's the way it works. The day that QM will be falsified, or that you can convince them that your programme is worth a bet, you are in. But if it really bothers you, I don't see why you don't do something real for a living, and work on your own in your free time (the way Einstein started off). You could also work on popular topics until you get tenure.

 

[Careful]

** But if it really bothers you, I don't see why you don't do something real for a living, and work on your own in your free time **


That is what my wife always says (but in her definition REAL excludes science). It is the old story that a senator or a successful businessman has the *****.


** You could also work on popular topics until you get tenure **

But then you are old and contentious that you made it

 

[vanesch]

** But if it really bothers you, I don't see why you don't do something real for a living, and work on your own in your free time **
That is what my wife always says (but in her definition REAL excludes science).

You should listen to your wife

** You could also work on popular topics until you get tenure **
But then you are old and contentious that you made it

Ok, but now you have enough influence to get your programme funded for other youngsters

And honestly, if by the time you're old, there has not yet been any experimental indication that QM is falsified, I think you can forget it, you will not be heard. So if you go for a more conventional career, you'll be ready, from the first indications of falsification of QM, to jump on the bandwagon (I'll testify for you, if you want, that you only did the conventional thing to keep in business, but that you are a True Local Realist ) ; or, if no such thing happens during your career, be happy that you didn't jump on the bandwagon . A win-win situation

Or even better: start a business, become rich, and start a foundation that gives grants for local realist research. You could even couple it to a Disney resort

 

[Careful]

**
Or even better: start a business, become rich, and start a foundation that gives grants for local realist research. You could even couple it to a Disney resort **

No, I should make a link between local realism and creationism so that I cash in many fat oil dollars already at this moment in time

 

[vanesch]

No, I should make a link between local realism and creationism

Well... you said that, not me !