joigus

Fair enough, @Eise. If not satisfy, I will try to answer to all your concerns. But 1st of all let me tell you that there are two statements of yours that worry me a bit, as they seem to "protect" some kind of future dismissal on your part of anything I can say. I'm sure that's not what you meant, because of your proven intellectual honesty: 1) and 2) You clarify the second point later, but I hope that doesn't mean 1) I cannot refer to quantum mechanics itself, in its closed mathematical form, in order to argue about what quantum mechanics itself means or implies. And 2) There's something about my statement of the EPR argument you don't agree with, but you reserve the right to bring it up later. Again, I'm sure that's not what you mean, but I need to be sure. Nothing would give me more intellectual satisfaction than giving someone like you full intellectual satisfaction. Then you go on to say, Sorry, bad choice of idiom on my part. "Sets the record straight" is too strong a statement if we want to be historically accurate. The reason is that Bell's observation on Bertlmann's socks whas a real epiphany for my own understanding, but I assume it's not necessarily so for everybody else, perhaps not even for Bell himself. Although it was for Murray Gell-Mann, as I think I've proven with the posting of the interview. It's only 4' 44'' and worth every second in diamond's carats. Particularly revealing is what he says at 3' 00'': This completely coincides with what @swansont has manifested elsewhere on these forums. It also agrees with my understanding of the question. And Bell's example of the socks personally was my wake-up call --or bell, if I may be allowed the pun. In my life, I've gone through two major epiphanies concerning these matters: E1) I was trying to explain quantum mechanics to my little sister circa 1995 when I suddenly realised you don't need to have any reduction of the wave packet if the wave function objectively represents infinitely many electrons from the get-go. I went to my trusty QM teacher and he told me Leslie Ballentine had already thought of that. Bummer, but nice. E2) I realised John Bell's observation on Bertlmann's socks clearly suggested/implied that the correlations --potentially, if you will-- say nothing whatsoever about locality or the lack of it. Was John S. Bell aware of it? I don't know, and I don't have access to his deathbed words, so... Then you say, This seems to be the subject of your "misgivings" concerning my statement of EPR. Well, Clause, Horne, Shimony, Bell, Von Neumann, Gleason, Kochen, and Specker, at the very least, took care of that. And that's because they assume a dependence of definite variables of any kind of which the all the possible observed values (eigenvalues) may be a function of. A local (meaning numeric value to numeric value) function (not involving non-commuting stuff amongst each other of any kind). In such a way that you can map hidden variable to eigenvalue point-to-point; value-to-value. The irrefutable consequence is that you can't. You need non-commutativity from the beginning. Von Neumann understood this. Coleman understood this. Gell-Mann understood this. But the message is sooooo incredibly difficult to get across, as Gell-Mann shrewdly points out. Let's call those quantum correlations colourful correlations if you will, just in order to see they imply nothing about spacetime. Colourful correlations are colourful at t=0 when the singlet state is prepared at one point in space. Colourful correlations are colourful at t=1 when the singlet state has evolved 1 light-second apart. Colourful correlations are colourful at t=2 when the singlet state has evolved 2 light-seconds apart. ... Etc. Are we there yet? Because if we are, we can proceed from there. Now we perfom a measurement, and all hell breaks loose, the worms get out of the can, and Alice's rabbit is deep down the hole. It's then when your comment about what the wave function objectively represents or to what extent it does is invested with the utmost relevance, and we may never be able to agree on what happens to the wave function, especially if you stick to your guns that the wave function objectively represents just a human idea, and nothing more. I do not hold that view, for reasons I may be able to explain later. It's such a pleasure to discuss the matter with you, @Eise.

This is a bit too strong of a statement for me to subscribe it, but once the mathematical basis is well established, yes, we should trust it. But experiments are the final deciders of everything in science. What I may have said is that arguing with just words is dangerous, because sometimes words carry hidden assumptions with them.

Not exactly or necessarily. I understand these things only in a very very qualitative way, so I can't help you much. Let's say I'm just an assymptotic observer . From what I understand, this dictionary has to be built with a lot of guesswork for each case. Doing a quick google search, and after filtering non-related stuff, you can find papers and seminars under titles like, AdS2 Holographic Dictionary Holographic dictionary for generic asymptotically AdS black holes Building a Gauge-Invariant Holographic Dictionary etc. I learnt about the holographic dictionary on Jacques Distler's blog, Musings. He's a mathematical physicist, string theorist, bitter enemy of Lee Smolin and the LQG people, so much/most of what he says goes right over my head. But it's interesting to take a look at what people with irreconcilable views say. You take a look at one, take a look at the other, and maybe the homotopy that connects both enlightens your mind. In a theory that's invariant under deformations, ascertaining what the observables are is no piece of cake, because coordinates don't mean anything much, and you have to find (bulk/interior) invariants --like the ones that Markus talked about many posts ago--, and relate them to invariants on the boundary. Or, perhaps, if the boundary theory is well-behaved, the other way around. I'm well out of my depth here.

CAVEAT: These words are absolutely key. Copenhagen's prescription that we do a normalised projection of the amplitude that's valid in all of space at one particular time --so that components of the wave function that were propagating away have to be killed off instantly or die down quickly enough-- is why the illusion of non-locality persists. It has no observable consequences for obvious reasons: The components that die down don't carry any observable consequence, as zero times anything gives zero. Now, we can say infinitely many things* about those components, that essentially are the same in minimal semantic terms. A very popular one is MWI. Those components are taken to an alternative universe. Bohm's double solution: Those components propagate away, like lost astronauts, without ever being seen again --empty waves. Let me give you another one: Those components become "transparent." "Transparent" being another fancy meta-variable that tells you they can never be measured. Etc. You can invent your own. That's what we call "the many interpretations of quantum mechanics." * If we want to save unitarity, linearity, and unblemished locality = Schrödinger equation

I don't think the Bible is so much concerned with swingers, as Abraham, Sarah and Hagar were the first "documented" swingers in history, if I remember correctly. On the other hand, I don't think the Bible took public nudity so lightly, to be honest. It was as much lenient with genocide as it was with swinging... You see where I'm going. I guess what I'm saying is: Do what you want to do as long as it doesn't harm or humiliate, or greatly embarrass, or create unnecessary problems, etc. to others. Same here. If we're talking about sex. If, we're talking about having a nice day at the beach, I agree with moon-tan-man. Not that I get many chances to tan my moon.

You caught me. It's Einstein speaking there. +1 My only excuse is that I was pressed to answer to a rather "entangled" physical question in terms of quotes of famous people, a field in which I'm anything but confortable. I'd rather discuss things in terms of mathematical statements under premises that have passed the test of time, both because they've been analysed by many competent people --theorists and experimentalists alike--, and because they've passed the experimental tests themselves. It is clear to me though that Bell --especially in his last years-- preferred to save locality and work instead on alternative extensions of quantum mechanics. I also know that from biographical testimonies that attest to the fact that Bell was very ambivalent about the interpretation of his famous theorem. Feynman and Gell-Mann, for example, shared the view that quantum correlations express nothing peculiarly non-local, but only carry with them a version of non-separability that's intrinsically quantum, and cannot be reproduced by any classical model. Most other important people in the field of theoretical physics, TBH, look at this with an absolute lack of interest. The reason why I cannot accept that this problem can be ascertained in terms of celebrity-quotes is, of course, that the views of different experts do not completely overlap, that sometimes they are ambiguous when in the process of understanding a particularly confusing topic, and that, perhaps as a consequence of that, their opinions end up changing with time. Because I'm not allowed to use mathematics, apparently, I will try to work on diagrams and logical outlines to further clarify my points. I do agree with your definitions 1 and 2 of --respectively-- action and correlation. My main point is that the implications of quantum correlations say nothing about locality, as they are encapsulated in the quantum state at t=0, when the singlet state was prepared, so they were there all along, and that I will stand by no matter what Bell, or anybody else, said at a particular time in history. What happens to the wave function after we make a measurement? We can discuss that if you, or anybody else, want. But that's a different matter. Let me add something else: Only people who adhere to the projection postulate of Copenhagen have this problem. That's where the fiction of non-locality arises. Why Bell might have been "fooled" by that at some point? --if that's the case--. I don't know. My best guess is that he was a pioneer in these things and he was still in two minds about some aspects. Do you agree with my statement summarising the EPR argument? If you do, we can go to the next step: Why David Bohm took the discussion to the case of spin, because in its original formulation in terms of position-momentum, the argument is flawed:

I agree, and they're all yours. What Mach thought about anything that can be applied to the interpretation of quantum mechanics interests me about as much as Heraclitus's views on the imac. You, as always, choose not to address any criticism. If this interaction that you claim is not physical, what is it? Metaphysical? Does it belong to an alternate reality? Is it the result of a midsummer's night dream? Will you finally answer at least to that? Quantum correlations that reflect non-separability. @MigL has told you, I have told you, @swansont has told you, Alain Aspect has told you, Murray Gell-Mann has told you, Sidney Coleman has told you. Will you finally take it home? The only thing that looks non-local is Copenhagen's old projection postulate, that require you to kill off all the components of the wave function that are ruled out by a measurement. But it is incompatible with the Schrödinger equation. So people don't believe it anymore. And again you're wrong. Newton did postulate an action at a distance. Newtonian physics has action at a distance written all over it. He did find it weird, and tried to defend himself from possible philosophical criticism with his famous hypotheses non fingo. I already did. Now you go back and read. I don't want this to be me doing all the work, while you dash off a note declaring your incredulity and proving to everybody that you haven't read anything. However, you should notice that physics is not resolved in quotes by famous people. It's more complicated. What are you saying? A photon is not a valid observer. The proper time of a photon is not a valid observable. The observed time is different for different inertial observers..., etc. If you ignore basic physical laws, I have no business with you anymore. I'm wasting my time, and I am no photon. Again? Really? How stupid do you think I am? I've given you the definition, and you've done nothing but dismiss it from an argument of incredulity. And you've done nothing but mumble something about a non-observable time. I'm not going to address any of your questions again. You stick with your unsupported unscientific incredulity. I'm trying just to honour @Eise's more than reasonable request to make the main points clear. Is this some kind of social experiment?

Probably something to do with this:

Agreed. I would only add that, on top of all that, quantum systems force us to think in terms of amplitudes, which are meta-probabilistic, if I may be allowed to use the term. And we don't exactly know what amplitudes objectively represent. Behind all this confusion, lies the question of the interpretation of quantum mechanics, ie, the several implementations of the principles of quantum mechanics that make no difference as to the experimental results, while at the same time seem to have completely irreconcilable ontologies underlying them. I think the confusion of many people with such issues as "non-locality," "collapse of the wave function," "Schrödinger cats" (macroscopic superpositions, etc.) comes from the fact that we haven't, as yet, totally understood what amplitudes are representing, how to implement measurements in a non-ambiguous way, etc. If I may be allowed to present a contention here --after all we are on the Speculations section-- is that we haven't totally understood the objective role that the gauge principle plays in all of this, but that's a topic for another --hopefully engaging-- thread. Please, mind my use of "objectively represent" instead of "is."

Not to mention that, according to @bangstrom, non-locality is. (drums for dramatic effect...) ... ... A non-observable time!! Ta da!! I would add, if it's non-observable, why bother with it at all? Again, let's strip it to its bare minimum: Bangstrom says: 1) Non-locality is a time 2) It cannot be observed Could it be that we agree in the end? Even, in a Donald Rumsfeld way, we may propose that we: a) Agree to agree b) Agree to disagree c) Disagree to agree d) Disagree to disagree Let them do their cleaning up their own house a little.

I agree through and through. What seems peculiar to me is that, if you insist on forcing the maths tell you something, and try to get S(entropy)=0, which would be sensible for a classical approach, you end up getting S(entropy)=infinity!, pointing to a, perhaps misleading --maybe just an artifact of the approximation--, "entropic catastrophe," instead of an entropy-less picture. I do too. What I find intriguing in the holographic approach is that, quantities that make sense in the bulk, perhaps do not in the complementary of the bulk* (the exterior bulk, STS,) but have a counterpart on the horizon. This, of course, must have to do with the hyperinteresting question of the holographic dictionary: How to translate observables that make sense in the bulk to observables that make sense on the horizon. This takes me back to mutterings that I've suffered for years now, and I will express here. What if Einstein's equations are valid locally** in the exterior of a certain compact surface, but not globally? Most fundamental static field equations have the form (schematically): [2nd-order differential operator](fields with assymptotic constraints)=(coupling constant)x(sources) (delta)F=S In the case of Einstein, delta is the non-linear combination of 2nd-order derivatives that constitutes the Einstein tensor G when acting on g (the metric, say the field), formally constructed in such a way that covariant differentiation D produces an identity: D(delta)g=DG=0 and, DS=0 In the case of Laplace, delta is the Laplacian, F is the electrostatic field, and S (the source) is the charge density. This makes sense for smooth charge distributions with spatial extension, but gets dramatically silly when S is a point charge. Could it be the case that this "approximation" can be made valid once a surface is chosen, but not extrapolated to be valid globally? (shrinking the surface to one point so as to express the field everywhere, as the singularity is suggesting.) * Maybe they do. I don't know enough to know. ** Or even only on charts.

This is not a definition. It works for you just because --no offence-- you seem to have very low standards on what constitutes a definition. "Spooky" is not a physical term. If you paid even the slightest attention to the mathematical formalism of quantum mechanics, you would understand this perfectly, as both any "blips" of information, or any "blips" of energy would have to travel in the form of "blips" in the square of the absolute value of the wave function --or the square of the gradient too, in the case of energy. That's what the quantum dynamics doesn't allow to do superluminally. (quoting your quote) Yes. Therefore => there can be no non-local interactions. Maybe we would have to go a step down and discuss what an interaction is. You say things like, What? The interaction is not physical? What is it then? Metaphysical? Because I'm keenly aware of the dangers of letting hidden assumptions slip into your arguments, I've found that it may be useful to strip the ideas to their bare minimum, and say only what they say, and nothing more. What comes next is a sketch of the history of these ideas. This is in order to satisfy @Eise's demands that we be clear. EPR: If you can predict with absolute certainty the result of an experiment without in any way disturbing the system, there must be some element of reality underlying it. Quantum mechanics says that certain pairings of observables are incompatible, say A and B. If I can exploit a conservation law that's valid for at least one of them, say A, in a bipartite system (A1+A2 = constant) and measure A in part 1, and B in part 2, I can infer what the value of A2 is without actually measuring it. I can, at the same time (within a space-like interval) measure B for 2, that is B2, with as much precision as desired, and I would have proven that quantum description of reality is incomplete, because I would have the values of A2 and B2, which quantum mechanics declares as incompatible. In a nutshell: Either quantum mechanics is incomplete, or your wave function would have to be updated superluminally, to make this incompatible character of A and B persist. I hope that is clear. If it is, we can all jump to the same page and proceed to Bohm, CHSH-Bell, Aspect. That means: why Bohm shifted the discussion to spin, what do the CHSHB correlations say and don't say, and what Aspect actually found. Then, perhaps, a discussion of science as perceived by the masses as well as relatively learned non-experts, and why this non-locality nonsense proves to be so persistent, the very same way that thousands and thousands of claims of possibilities for perpetual motion kept coming long after the question of its impossibility was perfectly understood by the theorists.

This is simply false. There is no such thing as non-local interactions. Please give references or stop repeating things you think you've heard or read. Your argument is logically indistinguishable from accounts that bigfoot is real... I'm sorry... "real." This reminds me of someone who once said something that was totally wrong. Come on. You can do better than this. Oh, wait... No, you can't.

When the quote function is playing up, I've found that copy and paste works better. But there seems to be a problem quoting, editing. Some functions seem not to be working.

Yes. Sorry. Same letter, different things. It's tradition, plus too few letters in the alphabet.

How h could possibly go to zero ? It's a constant. What we mean by that is the action (frequently named S) is enormous in comparison to h. This generally works fine when you take the solutions of the equations and make an expansion in powers of (h/action) or action+ h(something of order 1) etc. It's not to be applied directly to the equations of motion, for example. The Schrödinger equation would be meaningless. So it's something to do at the end, after having solved a problem, or in intermediate steps, but more carefully --like in the WKB (semiclassical) approximation, where you ignore terms in powers of h only when the powers are high enough.

Sorry. I wasn't clear. I totally agree with you that a classical BH has no entropy. The no-hair theorem guarantees that there are only three parameters that characterise a static BH: mass, charge, and angular momentum. IOW, there is only one state. IOW probability(Q,M,J)=1, and the probability of any other state is zero because there is no other state. Therefore, \[ S_{\textrm{CBH}}=-1\ln1=0 \] On the other hand, \[ S_{\textrm{QBH}}(A)=\frac{c^{3}A}{4G\hbar} \] and, \[ \lim_{\hbar\rightarrow0}\frac{c^{3}A}{4G\hbar}=+\infty \] So, considering a classical BH, "dressing" it with entropy, and trying to get to the classical version by (perhaps simplemindedly) having h go to zero, doesn't make a lot of sense. I'm willing to admit I may be just chasing shadows here.

Thanks for the compliment, but I can guarantee to you I'm no computer, and I'm no superman. I do have my kryptonite, like everybody else. I do spend a lot of time thinking, and reading, and doing calculations about these things, and trying to keep up to date on the experimental front. When I say something stupid, or just sloppy, I retract and apologise, and some people on these forums can bear witness to that. The "beable" idea is very interesting, but it would take us too far off tangent, I think. It's also too mathematical perhaps, if you take my meaning.

(My emphasis.) Here: (In this self-quote, I've just edited minimally for clarity, and highlighted the edited terms in boldface, as well as terms that point to the parts that you really had better read carefully before you embarrass yourself any further.) If you don't read the previous posts, you're only going to make this thread unbearably difficult to follow for everybody, including yourself. If I sounded demeaning to you, I sincerely apologise. It wasn't what I meant. But now I think it's obvious why I'm annoyed. If, for some reason, you don't like the maths, or you find its sheer mention annoying, or you don't think it's part of the argument, just tell me and I will try to re-phrase in some other way, because it is. It is an essential part of the argument. Don't just dismiss it or ignore it. I also remind you that you were the first in trying to make this personal: What does that have to do with anything? Please, use the quote function --as I did-- to direct me to your definition of non-locality, as I seem to have missed it.

(My emphasis.) It is even conceivable that the question will never be settled. It is even possible that, once the semantics of the problem is formulated in --mathematically-- totally unambiguous terms, we find out it corresponds to some of the questions that fall under the category of "undecidable" à la Gödel. Who knows? In fact, I do believe it may well be undecidable. If generalisations of QM is what this is all about, the sky of possible ideas is the limit. Let me give you an example. Non-relativistic Schrödinger's equation tells us that the evolution of the wave function is given by a differential equation that's 2nd order in positions and 1st-order in time. This is local out and out. But what if I'm allowed to modify the equation in such a way that there is a non-local term that only becomes relevant when a measurement is performed? The actual crux of the matter is, IMO, not so much whether the wave function represents something objective, as to how faithfully it parametrizes what's going on or, on the contrary, it parametrizes either more/less, as the case may be, than what we bargained for? Gauge invariance gives us a clue that it does give us much less --I'd say incommensurably less-- than we bargained for. As soon as you have gauge fields, you can change the wave function from any initial prescription \( \psi \) that's useful for, eg, collision theory, to any other that locally differs from your original choice by a (time-position)-dependent phase factor, and may be carrying other useful/significant/meaningful information. Who is to say the immensely rich landscape of infinitely-many gauge prescriptions does not carry a subgroup that tells us which one of the alternatives of a measurement is the one we are measuring? Because that's a --blatantly deliberate-- rethorical question, let me answer that explicitly, and face the possible consequences of any arguing against that may arise: Nobody.

I'm sorry I've failed. If I can keep your interest --the question is a really good one--, and until I can find a better way to explain it, please try to teach yourself as much as you can about --keywords-- individual vs collective interpretation of quantum mechanics. Pure states can be understood both ways, while mixed states can only be understood the second way. This piece of literature may be helpful: https://www.amazon.es/Quantum-Mechanics-Development-Leslie-Ballentine/dp/9810241054/ If you abide by the collective interpretation* of quantum mechanics all the way, the problem of measurement --in its original formulation-- simply dissolves before your eyes, and J. S. Bell** and M. Nauenberg's words in a rather obscure paper***, suddenly make sense, and you understand why he took so much interest in the double-solution proposed by Bohm and De Broglie. "Reduction of the wave packet" is synonym of "collapse of the wave function." It is only because the last generations have decided to re-coin the term to mean "decoherence in the density matrix," and only that, that the problem has become almost unintelligible. * In a nutshell: One electron wave function actually represents infinitely-many electron experiments. ** Probably the most misunderstood theoretical physicist of all time. This is my view. *** https://www.worldscientific.com/doi/10.1142/9789812386540_0003 I'll try to do that, I promise. Unfortunately, I will have to get involved in a lot of self-quoting. One part of the problem is that J. S. Bell shifted his position somehow during the time that he was thinking about this problem. So it's not impossible that he said some things here and there that do not conform to what his final position was. So I'll do my best. The problem with scientific literature is that sometimes you capture statements that took place when the problem was in the process of beeing understood. A good example of this is general relativity in the 60's. Lots and lots of peer-reviewed incorrect calculations made it to the literature. The final judge is, of couse, the experiment, and I'm sure nobody will ever by able to send any kind of superluminal signal. In my mathematically-biased mind, this is only too clear, as QM proposes nothing more than a finite-order differential equation, so unless this "model" is fundamentally wrong, no non-local effect can be claimed. But again, I'll try to explain it better. Yes, that's exactly what I'm saying. Now, give me a definition of a non-local theory, please, so that this discussion is not taking place in a conceptual vacuum. Exactly. It would have to be non-local. Intuitively, it's very clear: Because you need wave functions to represent quantum mechanical probability distributions, you would have to update the hidden variables in some non-local way to have some definite variables do the job of updating the wave function. But that would be only because you're trying to picture an internal classical world in the wave function to represent that updating in the wave function. If you actually believe that no "internal," "hidden-variable" representation of the results implements that updating, and quantum mechanics is sufficient to you, you are freed from that constriction. Sorry if I wasn't clear before.

No. And the fact that you keep ignoring the references I posted, and my best efforts to explain why, as well as other members', is making this ping-pong match really annoying. Again: https://en.wikipedia.org/wiki/No-teleportation_theorem https://iopscience.iop.org/article/10.1209/0295-5075/6/2/001 As I posted before, there are claims that generalisations of QM could explore non-locality. Generalisations of QM do not exclude the possibility of angels either. But we haven't seen any, and have serious reasons to believe there aren't any. For a theory to be actually non-local, not gibberish-non-local like what you're pretending to argue --I know how much you hate maths, but I have no better way to explain-- you would have to have dependence on arbitrarily high-order derivatives in the field variables. That's because you would have to have couplings of the form at 2 distant point \( x \) and \( x-a \), for example, \[ \varphi_{1}\left(x\right)\varphi_{2}\left(x-a\right)=\varphi_{1}\left(x\right)\left[\varphi_{2}\left(x\right)-a\varphi_{2}'\left(x\right)+\frac{1}{2}a^{2}\varphi_{2}''\left(x\right)-\cdots\right] \] so the fields would be coupled at distant points \( x \) and \(x-a\), and therefore would fall well outside the realm of any quantum theory. It faithfully follows the spatial dependence of the classical theories of which it is the quantised version. I've shown you arguments and authoritative claims that no quantum mechanical theory formulated so far --including quantum field theory-- is non-local. But you haven't answered any of it yet. Quantum mechanics is not non-local. Not in its mathematical form, for all we know it isn't, and not in the experiments. If you think it is, it is about time you start to present your case seriously, instead of repeating something you've heard. We are not children. If you don't like locality, go to another universe.

All systems that are maximally determined, yes. Those are called pure states. OTOH, it's always possible to prepare systems in non-maximally determined states, called mixtures or mixed states, and those are represented by a matrix built from products of the different sub-states, so to speak, in which the diagonal elements are the statistical weights of the pure states the collective state is made of. In other words, they represent quantum states in which not all the information has been monitored. The probabilities attached to the different "pure components" (wave functions) don't have necessarily a quantum origin. In that case there is a mixture of quantum uncertainties, and other uncertainties.

This example illustrates very nicely an analogue for quantum superpositions, but as any other classical analogue of quantum systems, it only illustrates one particular aspect of them. But I'm sure you agree that no classical analogy can actually embody all the properties of a multipartite quantum system, or of any other quantum system for that matter. The coin illustrates very well the indefinite nature of the intermediate states, but misses the correlations, and the fact that the state can be brought apart in the spatial components. The gloves cannot reproduce the total indefinition that characterises the state before a measurement is performed. So we're at a loss for analogies really.