Bohm Interpretation

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DrChinese

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Do you think Gell-Mann and Weinberg are amateurs? They both disagree with Bohr's <Copenhagen interpretation>
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FYI: Weinberg is famously one of the practical types, and has made his views well known - including in the reference you cited. So that would actually be a vote for Vanadium 50's position. It also would echo the concerns that JustinLevy had which started this thread.

Not trying to come down on one side or the other, just pointing out that we will probably fulfill the objective our moderators want us to pursue if we focus on the scientific arguments. There are naturally going to be big names on various sides of various interpretations. The Bohmian interpretation is a legitimate subject of research, but one which has yet to produce a big "win". JustinLevy is asking what the attraction is, and I think the question deserves a straight answer. I hope the references I supplied will get anyone started on the matter who wants to know more. I got these from some of the BIers here via another thread. (I should not be considered a subject matter expert on BM/dBB, I am learning too and trying to see what it has to offer.)
 
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I think that question points out exactly why professionals aren't interested in this at the level amateurs are. If the various interpretations give identical results, there is no scientific basis for distinguishing between them. Indeed, who's to say that only one can be right? It's like asking whether you believe in configuration space or momentum space: both will give the same answers. Often one is less work than the others.
Interpretations are the starting points for future theories, so there is a point of preferring one or some of them if one tries to develop some more fundamental theories.

Of course, for most physicists this is not the job they get paid for. Their job are some applied quantum problems which are interpretation-independent. But the real great revolutions in science have not been done without care about metaphysics and methodology.

So, in some sense the question is what you want to reach in science. If you want to play small, take some application and don't care about fundamental physics. If you want to play big, you have to care about foundational questions.
 
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But I can't believe, in the long run, it makes sense to construct an interpretation that gives identical results as what is already taught in textbooks. So my interest is to find some delta, and I personally think a truly different interpretation will yield a different - and hopefully testable - prediction eventually. That is why I wonder about radioactive decay, virtual fields, etc.
I think it makes a lot of sense to clarify the foundational questions. And in particular to clarify if there are reasons to give up such fundamental principles like realism, causality and so on.

Norsen (2006): Against 'Realism' This article is one that I am in strong disagreement with, and Norsen and I have debated this point endlessly on this board in the past.
I like this paper. Even if I'm not "against realism" but consider myself as a defender of realism. The notion of realism I defend is the metaphysical one of this paper.

Nonetheless, if you accept Norsen's argument, then the Bohmian viewpoint makes infinitely more sense. However, I completely reject the idea that Bell's Theorem does not include Realism as an assumption as it is easily to point to.
There is something one has to assume. But this "something" is an extremely weak assumption.

And if one rejects this very weak notion of realism, one does not obtain very much. The weak notion of relativistic symmetry, which is only about observables, is compatible with pilot wave theory and this weak notion of realism anyway. Thus, the weak notion of relativistic symmetry does not give a reason to reject realism. And the strong, realistic notion, which requires that reality has Lorentz-symmetry, has to be given up anyway, with or without metaphysical realism.

So, while I continue to think (after Norsen) that there is some hypothesis worth to be named "realism" and used in Bell's theorem, I think the case for not giving up this hypothesis is very strong. And if we don't give it up, we have to accept non-locality, or a preferred frame.

But none of that changes anything, and I can't think of any non-Bohmian that agrees with Norsen's hypothesis. And certainly I can't think any anyone actually doing experimental work in this area (a la Zeilinger and many others) who have ever mentioned that Bell's Theorem presumes non-locality.
I prefer to care about content arguments instead of ad hominem arguments. What the people working in certain domains think is a sociological question, not a physical one. And the situation in science today is one of extremal uncertainty of the working conditions (with jobs which end after a few years, which is much more uncertain than everything else one can imagine). The ideal of independent science is something very different from what we find today in professional science.
 

DrChinese

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So, while I continue to think (after Norsen) that there is some hypothesis worth to be named "realism" and used in Bell's theorem, I think the case for not giving up this hypothesis is very strong. And if we don't give it up, we have to accept non-locality, or a preferred frame.
If you would like to discuss the pros and cons of Norsen's paper (and I would be happy to do so), we should start another thread for that.

My point about Norsen's paper is that IF you accepted his basic argument - as you say you do - THEN you naturally wind up with a favorable perspective on Bohmian interpretations. That is not the only way to get to that point, but I think it is natural. Because then, you essentially view Bell's Theorem as a rejection of locality - as Norsen essentially does, since he thinks that "naive realism" (his words) is not so relevant to Bell's Theorem.

(By the way, I laughed when Norsen attached the word "naive" to a respectable viewpoint. Apparently, no one bothered to explain to Einstein that his cherished viewpoint was in fact naive. Anyway, realism - robust, healthy and meaningful - is fully present in Bell's Theorem as an assumption and there is nothing weak about it. It is difficult to imagine how Bell's famous paper can be considered absent the arguments presented in the EPR paper - in which the fmaous phrase "elements of reality" is defined - given the title Bell chose. I think Bell could have labeled his realism assumption more clearly, but that does not change the argument or its impact.)
 

Vanadium 50

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Interpretations are the starting points for future theories
I'm not sure I buy this. I recognize that people would disagree with me on this (I once had dinner with my friend and erstwhile collaborator John Cramer who tried the whole time to persuade me to adopt his point of view) but I don't think this strategy has borne much fruit in the past.

I think history has shown that theoretical developments tend to be driven by either internal inconsistencies in the theory, or disagreements with the data, rather than different interpretations of the same theory.
 

DrChinese

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I'm not sure I buy this. I recognize that people would disagree with me on this (I once had dinner with my friend and erstwhile collaborator John Cramer who tried the whole time to persuade me to adopt his point of view) but I don't think this strategy has borne much fruit in the past.
I agree, history shows there is no obvious pattern regarding periods of rapid scientific advances.

I know this is off-topic, but does Cramer (or maybe yourself) have anything new on the horizon regarding quantum erasers, experimental tests of the Transactional Interpretation (Absorber theory) or similar going on? Last I saw, he was talking about a variation on Dopfer's setup.
 

Vanadium 50

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He's been trying to work on these experimental tests. As you probably know, there is some dispute as to exactly what these experiments measure, and if different interpretations do, in fact, give different results.
 
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I'm not sure I buy this. I recognize that people would disagree with me on this (I once had dinner with my friend and erstwhile collaborator John Cramer who tried the whole time to persuade me to adopt his point of view) but I don't think this strategy has borne much fruit in the past.

I think history has shown that theoretical developments tend to be driven by either internal inconsistencies in the theory, or disagreements with the data, rather than different interpretations of the same theory.
The measurement problem is, of course, an internal inconsistency of some interpretations of quantum theory. Thus, if pilot wave theory leads to some future development, one can also claim that it was driven by internal inconsistencies of standard quantum theory.

I'm not a specialist in history, but have my own experience: I have started with an interpretation of GR and after this switched to an alternative theory of gravity.
 

Demystifier

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How/can does Bohm Interpretation and formulation result in Quantum Field Theories? Is there relativistic formulations of Bohm-quantum mechanics?
For the second question, see
http://xxx.lanl.gov/abs/0811.1905 [accepted for publication in Int. J. Quantum Inf.]
For the first question, wait a few days to see how the results in the paper above can be extended to QFT.
 

Demystifier

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I asked for references in the past about that : what does Bohm-Broglie say about scaling violation in QCD ? This is an established fact.
It says the same as standard QCD says, nothing new.
 

Vanadium 50

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The measurement problem is, of course, an internal inconsistency of some interpretations of quantum theory.
I don't think this will be universally agreed. If this is an internal inconsistency, it's certainly of a different nature than (e.g.) the ultraviolet catastrophe or the non-unitarity of Fermi's weak force theory.
 

Demystifier

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I don't think this will be universally agreed. If this is an internal inconsistency, it's certainly of a different nature than (e.g.) the ultraviolet catastrophe or the non-unitarity of Fermi's weak force theory.
You probably meant non-renormalizability of Fermi's theory?
By the way, in modern view of QFT as effective theory, non-renormalizability is not viewed as a true problem.
 

Vanadium 50

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You probably meant non-renormalizability of Fermi's theory?
No, I meant what I wrote. If you calculate, e.g. electron-neutrino scattering in Fermi's theory, the cross-section violates unitarity at about 200 GeV.
 
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Just curious, if we interpret the result of the calculation for 200gev literally, what nonsense is predicted exactly?
 

Demystifier

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No, I meant what I wrote. If you calculate, e.g. electron-neutrino scattering in Fermi's theory, the cross-section violates unitarity at about 200 GeV.
Are you talking about a calculation on the tree level, one loop level, or something else? :confused:
 
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It says the same as standard QCD says, nothing new.
That's great. You have a reference explaining the interpretation of a classical non-relativistic potential for the pilot wave of a highly relativistic virtual gauge particle ?
 

Demystifier

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That's great. You have a reference explaining the interpretation of a classical non-relativistic potential for the pilot wave of a highly relativistic virtual gauge particle ?
Not exactly. I have a reference explaining how measurable results of ANY quantum field theory (in flat spacetime) can be interpreted in terms of relativistic particle trajectories guided by a relativistic pilot wave that represents the physical QFT state.
Would that be great enough?
 
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Not exactly. I have a reference explaining how measurable results of ANY quantum field theory (in flat spacetime) can be interpreted in terms of relativistic particle trajectories guided by a relativistic pilot wave that represents the physical QFT state.
Would that be great enough?
Sure, please.
 
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arXiv:0904.2287 (hep-th), it should appear tomorrow.
You will forgive me for being unaware of it :biggrin:
More seriously, I would have preferred a published paper, but I will certainly take a look at your reference.
 

Demystifier

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More seriously, I would have preferred a published paper, but I will certainly take a look at your reference.
Well, in the paper you will also see the references on some previously published papers on this stuff. For example, one of them is published in Phys. Rev. Lett.
 
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Well, in the paper you will also see the references on some previously published papers on this stuff. For example, one of them is published in Phys. Rev. Lett.
Then maybe you can provide the references to published papers first ?
 

Vanadium 50

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Just curious, if we interpret the result of the calculation for 200gev literally, what nonsense is predicted exactly?
You get probabilities that are not between 0 and 1.

Are you talking about a calculation on the tree level, one loop level, or something else? :confused:
I'm not sure how one could even do loops with Fermi's 4-fermion theory. Without the W, there's not much to "loop".
 
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Well, in the paper you will also see the references on some previously published papers on this stuff. For example, one of them is published in Phys. Rev. Lett.
I note one thing. It has been several times already that on this forum I request for a good reference dealing with a relativistic gauge invariant bohmian interpretation. I have already obtained "work in progress, we'll solve it soon". But never "I'll put it on arXiv tomorrow".

Once again, I'd really appreciate if you can point us to a published, peer-reviewed, publication. Your tomorrow article might take weeks to be published. I'll have lost interest in this discussion by then.
 

Demystifier

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For humanino:
[10] Phys. Rev. Lett. 93, 090402 (2004)
 

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