Does Decoherence and Entropy Relate to the Second Law of Thermodynamics?

[Maaneli]

Again, that's just silly. The Wikipedia, properly interpreted, is one of many extremely valid references for scientific debate.

Again, that's just silly. The Wikipedia, properly interpreted, is one of many dubious references for scientific debate.

I'm afraid I have no idea what you are talking about. I have seen the forum rules, and see zero issues with how I've handled outside references.

I'm afraid I have no idea what you're talking about. I have also seen the forum rules, and see the obvious issue with how you've handled outside references.

I don't think the phrase "blatantly false" means what you think it does. The claim of mine that you seem to be referring to is that the "measurement problem" is a many-headed dragon that means a slightly, or vastly, different thing any place you encounter it. If you feel that is false, I invite you to invoke something other than your standard penchant for "argument by assertion".

I don't think the phrase "blatantly false" means what you think it does. The claim of mine regarding the measurement problem that you seem to be referring to is clearly and consistently discussed (as I have presented it) in any text or review paper on QM foundations. See, for example, Jammer's "The Philosophy of Quantum Mechanics", Bub's "Interpreting the Quantum World", Torretti's "The Philosophy of Physics", Butterfield's et. al's "Philosophy of Physics: in the Handbook of Philosophy of Science", Schlosshauer's "Decoherence and the Quantum-to-Classical Transition", that Schlosshauer paper I gave you (which really is quite representative of these other works), Bell's "Speakable and Unspeakable in Quantum Mechanics", Bohm and Hiley's "The Undivided Universe", Omnes' "Understanding Quantum Mechanics", Auletta's and Parisi's "Foundations and Interpretation of Quantum Mechanics: In the Light of a Critical-Historical Analysis of the Problems and of a Synthesis of the Results", Elitzur and Dolev's "Quo Vadis Quantum Mechanics", Albert's "Quantum Mechanics and Experience"...Need I pile on more?

Goodness, I've been to no conferences on the foundations of QM? What am I doing having a considered opinion? Of course no one should ever say anything about a science subject they have not been to a conference about, whereas anyone who has been to a conference is immediately to be regarded as an unimpeachable authority. That's pretty much your logic here.

As usual, you totally distorted my remark (much like a Karl Rove Republican). My point in calling you out on your lack of exposure to the mainstream views (either through conferences or well-established texts and review articles like the one's I cited above) is to instill some pause and doubt within your religious self-confidence. Imagine if I never went to a string theory conference or never read any of the texts or review articles on string theory, but then made a sharp and confident criticism about the AdS-CFT correspondence and claimed that most of the string theorists are just confused about it. You and everyone else would have every right to be skeptical of my credibility. Similarly here with you. If you really think you have it figured out so well and that others are confused, I dare you to participate in the next QM foundations conference at the APS in Maryland (this April) and put your ideas out there and see if you can defend them against all the QM foundations specialists. Here, I'll even give you the website link so that you can write to the organizers and request an invitation (though, I predict you'll wuss out instead):

http://carnap.umd.edu/philphysics/conference.html

On the other hand, I will find occasion to read that article, but anticipate that I will either find occasion to agree with its conclusions, or point to flaws in its arguments. You know, "analysis".

Good for you. I think you'll get a lot out of it.

If anyone in the field doesn't think they are confused about the measurement problem, it is they, and you, who have their head in the sand. I'll spare you all the quotes where people like Feynman said that better.

Great, thanks for proving my earlier point. That's why your credibility is so damn weak here. Once again, I invite you to the Maryland conference to put your money where your mouth is.

You like that word, "disingenuous", don't you?

Yes it aptly describes you.

Now let's look at what I'm actually saying. Everyone knows we can pay lip service to the "measurement problem" by referring to a vague sense that we don't know why a theory that is apparently based on deterministic time evolution yields probabilistic outcomes. However, when one digs into that problem, one finds that there are all kinds of different facets to that problem, some with fairly easy solutions, some that will never have any solution because it would go beyond what science is capable of. Thus whenever these "experts" who've gone to conferences refer to "solutions to the measurement problem", they are using vastly imprecise language. That's just obvious to me, I'm sorry that I don't need to go to a meeting to say that.

That's because you've never bothered to study how these other QM formulations like MWI, deBB, stochastic mechanics, propose to solve the measurement problem. Here, do yourself a favor and do some research:

What you always wanted to know about Bohmian mechanics but were afraid to ask
Oliver Passon
Journal-ref. Physics and Philosophy 3 (2006)
(read in particular section 3.3 on pages 10-11)
http://arxiv.org/PS_cache/quant-ph/pdf/0611/0611032v1.pdf

The "Unromantic Pictures" of Quantum Theory
Authors: Roderich Tumulka
Journal reference: J.Phys. A40 (2007) 3245-3273
http://arxiv.org/abs/quant-ph/0607124

But let me give some examples, instead of following your approach of argument by sheer assertion. What are some aspects of the "measurement problem" that have been solved? Well, the obvious one is decoherence, which explains the mechanism for how a closed system can evolve unitarily into a state that, when projected onto open substates, generates a mixed state. The BI was already well aware that this would happen, but decoherence gives a way of saying how that works out. To me, the key contribution of decoherence theory is in verifying the stability of the pointer states. But more importantly, we should note that classical physics already used that result for centuries prior to quantum mechanics, so we should see that as more of a "sanity check" than some kind of fundamental discovery.

As I said before, I agree with you about the utility, value, and importance of the decoherence formalism in solving part of the measurement problem. So, once again, there is no disagreement here.

So what aspects of the "measurement problem" will never be solved by any science? That's easy, any aspects that are intrinsic to the assumptions we make whenever we embark on the scientific path. Here we find issues like the need for idealizations like objectivity, subject/object separation, conventions about reason, and so forth-- all the elements that go into the scientific method that we can pretend, but should not believe, are precise rather than fuzzy aspects of the otherwise seemingly axiomatic structures we call theories.

This is total gibberish. You said absolutely nothing substantive about the measurement problem.

He was talking about a different one of the many heads of the "measurement problem" dragon, to wit, the problem that science is based around results that are highly nongeneric to the theory of quantum mechanics.

Yes, he was talking about one aspect of the measurement problem (as I said); but this was not the extent of his understanding as you implied.

According to your interpretation of "wave/particle duality", perhaps. However, the sensible way to interpret that phrase is simply that particle behavior is describable with wave functions. Look how I got "particle" and "wave" into that completely uncontroversial sentence that has zero need for interpretations of QM-- that's wave/particle duality.

Pfft. You unjustifiably assumed the very thing you were trying to prove (in other words, you begged the question). Tell you what, take a course in basic logic, and then we'll pick up this discussion again.

Personally, I think so much of what is written about the CI is just plain misguided, which is also why I said that most people who criticize it either don't understand it, or have morphed it into a kind of strawman to appease the very prejudices that it was intended to avoid appeasing. We covered all this already in the choice to use BI instead of CI-- you're backtracking.

I agree with everything you say about CI, and I'm glad you used BI instead of CI to refer to Bohr, and hope you continue to do so.

The latter problem is not "solved" by any of the interpretations we've talked about, any better than "God did it" solves that problem.

It's no surprise to hear that coming from a creationist. But I should remind you that your comment is not at all a scientific one, nor even a serious philosophical one, and I would also remind you that there is in fact an amateur philosophy discussion forum here that you can move to if you want to make vacuous statements like that. But please don't bring nonsensical statements like that into a physics forum.

Usually, in physics we are well aware that there is no such thing as a "fundamental" theory, as all theories will begin with the postulation of undefined entities. Why people are under the illusion that quantum mechanics is any different was always been a mystery to me, but as I said, I see it as a classic example of "all past science has been wrong, but today we have it right" kind of thinking.

I agree with everything you say here, but this is an entirely different issue.


I won't waste my time responding to your inane criticisms about the use of the word "predict". Not until you actually learn about the quantum theories you're criticizing.

The MWI asserts the existence, yes existence, of worlds that we have no interaction with and no empirical connection to. The justification for that is entirely that it allows us to imagine something we should not bother to be so foolish to imagine, that our mathematical concepts can dictate to reality. Yes, I would indeed describe that as the very definition of what is nonphysical-- and what I called not even wrong.

Well I guess you would say the same about string theory? Then that's your right, but you still haven't given an argument (other than ad hominem's) for why your criterion should be preferred over any other. Personally, I think this just makes you a naive positivist. And there is no logical reason to think that everything that exists in the physical world should be empirically detectable by humans, even in principle. And if a mathematical theory makes all experimentally confirmable predictions, but also predicts some phenomena that are (or seem) beyond the capability of human detection, that poses no logical or consistency problem for the theory whatsoever. It only poses a problem for YOUR philosophical prejudice about how the physical world "should" work.

Actually, I did, but I'm happy to do it again: what is "physical" is all that we can objectively and repeatably measure (at least in principle, we always have to allow for technological limitations). I would say that statement is the very core concept of all of physics, hence the word.

See above.

Physics theories do not "predict" other physics theories!

Actually they do. Special relativity predicts classical mechanics in the v << c limit.

I'll break here, my response is long enough.

 

[Maaneli]

You pointed to the Nazi bomb effort, which you are apparently unaware that Heisenberg claimed he intentionally sabotaged.

No actually Heisenberg never made that claim. That's a myth, just like the myth that Einstein was a poor student in secondary school. I would cite you references, but I suspect you would just ignore them for your own convenience.

I mean, well, it leaves no tracks.

I mean, well, what do you mean by "tracks"?

Goodness, you are massacring the word "predict" again. You can certainly choose to force the particle to leave literal "tracks" by deciding you are going to, by measurement, establish a concept of a trajectory, but you don't need dBB for that, simple QM accomplishes that just fine, and the predictions (using the correct meaning of that word) are all identical. That's what I mean by dBB leaving no tracks-- nothing that distinguishes it that isn't happening entirely in our minds (i.e., no tracks).

See all my references and comments about quantum nonequilibrium in deBB.

As I already pointed out with the die analogy, the determinism of the Schroedinger evolution is not sufficient to establish a deterministic process. So no, the determinism does not come from the Schroedinger equation, and I don't need to go to a meeting on quantum interpretations to see that basic logic.

I guess you were never any good at math, otherwise you would know that the Schroedinger equation is a linear PDE, and that such equations are perfectly deterministic in their time-evolution. And you don't need to go to a meeting on quantum interpretations to see that basic logic.

Please stop misusing the word "predict", it is almost painful for me given that my entire point is we must always bear in mind the empirical foundations of science when we interpret what science is doing. But even if we substitute the word "derives", your statement is still backward logic-- the deBB starts from the Born rule and reverse engineers a picture that can be said to lead to it. But the assumptions of the deBB are no less arbitrary than those of the Born rule, so no, nothing is being fundamentally "derived" there, it is just a shell game, a basic parlor trick.

Nope, sorry, wrong again. Do yourself a favor and do some research. Here, I'll start you off:

Quantum Equilibrium and the Origin of Absolute Uncertainty
Authors: Detlef Dürr, Sheldon Goldstein, Nino Zanghí
Journal reference: Journ. of Statistical Phys. 67, 843-907 (1992)
http://arxiv.org/abs/quant-ph/0308039

Dynamical Origin of Quantum Probabilities
Authors: Antony Valentini, Hans Westman
http://arxiv.org/abs/quant-ph/0403034

Hidden Variables, Statistical Mechanics and the Early Universe
Authors: Antony Valentini
Journal reference: 'Chance in Physics: Foundations and Perspectives', eds. J. Bricmont et al. (Springer, 2001), pp. 165-181.
http://arxiv.org/abs/quant-ph/0104067

http://www.fourmilab.ch/rpkp/valentini.html

Proof That Probability Density Approaches |ψ|2 in Causal Interpretation of the Quantum Theory
David Bohm
Phys. Rev. 89, 458 (1953)
http://prola.aps.org/abstract/PR/v89/i2/p458_1

Model of the Causal Interpretation of Quantum Theory in Terms of a Fluid with Irregular Fluctuations
D. Bohm and J. P. Vigier
Phys. Rev. 96, 208 (1954)
http://prola.aps.org/abstract/PR/v96/i1/p208_1

Actually, I highly doubt it is logical to think that the deBB could have been arrived at first, because of its structure as QM with a facade erected in front of it to make it look like a deterministic theory (even though it does not allow anything more to be determined than does QM).

Actually, the deBB was discovered first (in 1923) by Slater et al. as a photon theory (see the reference therein):

N. Bohr, H.A. Kramers and J. C. Slater, “The quantum theory of radiation,”
Philosophical Magazine 47, 785-802 (1924). Reprinted in Sources of Quantum
Mechanics, see Ref. 7.

The Schroedinger equation was also derived in the same year as Schroedinger's original derivation, but via the Madelung fluid (the same equations as deBB):

E. Madelung, “The hydrodynamical picture of quantum theory,” Z. Phys . 40, 322-326 (1926).

I am confident that if one digs into the assumptions made there (which one would need to have an expectation of it being worth one's while), one will quickly see that what is being tested there is not deBB theory, but rather, some offshoot that makes additional assumptions inspired by it.

Your confidence is baseless because you don't even know the basics. This is actually part of the standard deBB theory whether you like it or not. Again, do some research first. I gave you all the references you need.

In identifying those additional assumptions, one will destroy the claim that this is a fundamental result of the deBB by simply finding a way to embed those exact same additional assumptions into a more CI-type rendition of quantum mechanics.

I would like to see that!

What I think is that no one can know which pedagogy will inspire which new discoveries. As such, I never deny the value in exploring alternataive pedagogies like the deBB or the MWI.

Oh, right, I see. You think alternative pedagogies like deBB or MWI are no better than saying "God did it", but you never deny the value of exploring them. You would be a perfect candidate to join Bill Dembski and the Discovery Institute and do some research on how ID and creationism can "explain" some other explanatory "gaps" in evolutionary biology.

My objection is the simple observation of how people fail to recognize the role of prejudice in preferring one set of extraneous ontologies over another, when in fact, the sole non-prejudicial objective must be to identify whichever interpretation has the least extraneous ontology that we are intended to take as serious efforts to establish how reality actually works.

And decoherence alone is not enough because it says nothing about the problem of definite outcomes.

Thank you for identifying interesting papers that attempt to address the "mind-body" problem. I am aware that "serious" efforts are made at addressing that, just as I am aware that serious efforts were made by Newton and others to achieve alchemy.

Missed the point utterly (as usual).

Of course you are, that is your default position on all matters-- that your own expertise vastly outweighs that of the other, and this justifies relaxing the requirement to cite actualy evidence in support of your opinions.

It certainly outweighs yours. And I guess its convenient for you to just ignore all the evidence I give you.

Actually, I am also aware that many scientists like coffee, and some have a deep faith in God.

Oh, you mean Creationists like yourself?

On that score, it is interesting you mention Tegmark, because although I realize he has done many good things in cosmology, it brings to my mind his "quantum suicide" scenario. Do you know it? (I assume is must have come up at one of those interpretation meetings you frequent.)

Yes I know it.

Now, I have not the imagination to concoct a more blatant example of the kinds of absurdities that one can be led to take seriously if one forgets the correct direction of logic in science (from reality to conceptual structures, not the other way around).

Your prejudice once again.

You were supposed to see that as a refutation that our standards should be that low, not as an argument that we should accept my alternative.

Well, if you were reading carefully, I never said deBB or MWI or GRW is the best possible solution to the problem of definite outcomes. I just said that they DO constitute solutions to that aspect of the measurement problem (and yes, they are much more sophisticated than just saying that "God did it" like you want to believe), and that they incorporate decoherence very naturally. In fact, I personally have a much more radical view of the interpretation of QM.

The argument I actually presented was never that the MWI or deBB were "illegitimate", but rather they include extraneous ontologies that are motivated entirely by prejudice, whereas the BI is really the one that sets out to use the minimal ontology that is intrinsic to science itself.

I have no problem with being a minimalist in that sense, or for that matter, what I like to call an "agonstic realist". But I do have a problem with you claiming that there is no mystery or problem of definite outcomes that doesn't justify for a deeper physical explanation, or that deBB and GRW are not empirically testable, or that they are no better than "God did it" (which really is disingenuous).

The rest of your comments were a load of rhetorical BS, and I won't waste my time deconstructing them.

 

[Maaneli]

Please keep in mind that in discussions about interpretations of quantum theory, half of the argument is philosophy based, and half of it is theory based. So it is entirely normal to have different viewpoints, and there's no point in trying to argue why one is "better" than the other. It is important to recognize this. What is problematic and what isn't, comes close to the philosophy of science itself. None of the current interpretations are totally idiotic, and none of them are without conceptual difficulties. The choice is often driven by what properties one values more than others. There is no "obviously correct" interpretation - otherwise there wouldn't be any debate amongst knowledgeable people for almost a century.

I am not trying to argue about what I think is the most correct interpretation. I am simply trying to keep people like Ken G from thinking that he already knows the answers or that the problems are simpler than they really are. The measurement problem (in particular, the problem of definite outcomes) is primarily what motivates and justifies the various QM interpretations beyond decoherence theory, and I think people like Ken G need to understand that and stop arrogantly belittling physical theories that are more ambitious than his own naive positivism.

I'm not going to lock this thread right away - but steer it into a constructive discussion, or it will be locked.

Honestly, I think the only way this discussion can ever become more constructive is if Ken G starts doing some serious reading and thinking about the current theories and opinions in QM foundations (and philosophy of science!), understands the precise facets of the measurement problem, and infuses himself with some more self-doubt (especially about the meaning of science!). The mentality that he currently has is only detrimental to the progress of physics and science in general.

 

[ZapperZ]

Obviously, vanesch's warning falling on deaf ears. So this thread is done.

Also be warned that the NEXT time this occurs again (and trust me, it will since the question of "interpretation" comes back very often like a bad habit), there will be NO warning given to all those involved prior to any actions taken.

Zz.