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Insights Interview with Astrophysicist: Adam Becker - Comments

  1. Apr 13, 2018 #121

    vanhees71

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    Of course, I don't claim that. My point simply was that all hitherto done experiments with entangled photons and other systems to test Bell's inequality against the prediction of its violation by QT are all fully understood within relativistic local microcausal QFT and thus by construction exclude both spooky-action at a distance and the possibility of retrocausality. All there is is the state preparation in the very beginning which implies the correlations described by entanglement, and all experiments agree with the predictions of QT (particularly relativistic QFT). I don't expect any changes with this conclusion when using humans for the switching decision, but of course one has to do the experiment to be really sure. Physics is indeed an empirical scienc!
     
  2. Apr 13, 2018 #122

    vanhees71

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    I don't use a cut. I use real-world macroscopic equipment to prepare states and perform measurement (well, I let my experimental colleagues do that, because I'd for sure mess up the experiment being a theorist ;-)).

    I don't claim to solve any "measurement problem". I deny that one exists do begin with for the simple reason that we are able use QT to successfully predict the outcome of measurements (in terms of probability and statistics).

    Landau and Lifshitz use indeed a Copenhagen-like flavor, but they hardly discuss interpretational issues at all. Weinberg doesn't take any side but says that the interpretational problem is undecided, although I also fail to see where this apparent problem might be for the reason just given. Weinberg's chapter on interpretation is, however, among the best I've read about the issue (which is as valid for the entire content of this and all his other textbooks). Nevertheless I'm not sharing his opinion on the final dictum on interpretation.
     
  3. Apr 13, 2018 #123

    atyy

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    That is a cut, because the "macroscopic" equipment is not included in the quantum state.

    That alone would be ok (not my position, but certainly one that is coherent and attractive), but you often add that the macroscopic equipment can be included in the quantum state by suitable coarse graining (without hidden variables or MWI) - that would not be ok.
     
  4. Apr 14, 2018 #124

    RUTA

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    Silberstein and I gave a talk at Univ of Maryland on Wed. Afterwards, we had dinner with Jeff Bub and he had some interesting responses to Adam’s book. He was not happy that the book made it seem like he wasn’t aware of Bohm’s interpretation when he was Bohm’s grad student. In fact, Bohm wasn’t taking any more students when Jeff was picking an advisor, but Bohm took Jeff precisely because Jeff had done an undergrad thesis on Bohm’s interpretation. More stories from Bub to follow :-)
     
  5. Apr 14, 2018 #125

    atyy

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    So did Jeff Bub buy Adam's book?
     
  6. Apr 14, 2018 #126

    RUTA

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    He was interviewed for the book, so of course he received a complimentary copy :-)
     
  7. Apr 15, 2018 at 10:11 AM #127

    martinbn

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    Why is this a cut? If you study a particular system you can ignore the rest of the universe or use an approximate description of some other systems if that is good enough. It would be a cut only if you say that all of the rest cannot be in principle described by quantum mechanics and you need at some point a classical system.
     
  8. Apr 15, 2018 at 10:44 AM #128

    RUTA

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    Here's another Bub story from our dinner on Wed related to the book. Adam is bemoaning the fact that so many physicists don't bother to articulate their ontological assumptions concerning QM, indeed some even deny having them altogether! After arguing against this attitude, Adam says physics students should at least be shown various interpretative options for QM.

    At dinner, I told Jeff I hadn't seen any real progress in the debate over QM interpretations since I began work in the field in 1994. We get new experiments, some of which are even motivated by a particular interpretation, but then everyone brings out their favorite interpretation and explains the experimental result to their own satisfaction. The people I first met in foundations of physics (FoP) in 1994 are still today arguing for what are basically their same interpretations from 1994. Jeff said he sees FoP splitting along two lines -- the old line of hackneyed interpretative debate and a new line exploring the deeper mathematical underpinnings of quantum theory, e.g., as with quantum information theory. He thinks the future of FoP lies in this new line.
     
  9. Apr 15, 2018 at 12:46 PM #129

    PeterDonis

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    That's because all interpretations make the same predictions for all experimental results; they have to, since they all use the same (or equivalent) mathematical machinery.

    To make progress, someone needs to come up with a new theory--different mathematical machinery that makes the same predictions for experiments that have already been done, but makes different ones for some experiment that hasn't yet been done. If the new theory also rules out some subset of interpretations of current QM, then running the new experiment might help, if it confirms the new theory (and therefore contradicts current QM).
     
  10. Apr 15, 2018 at 2:13 PM #130

    RUTA

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    As a physicist involved in this program, I agree completely. I started working on an interpretation of QM so I could have an ontology for all of physics. In other words, I want an ontology that is just as good for GR as it is for QM. I knew that such an ontology would change the way we view reality and consequently lead to new physics, e.g., when we changed from geocentricism to heliocentricism. And that's what excited me about FoP. But, I found many participants didn't even care if their interpretation was compatible with physics other than QM. I can't tell you how many talks I've given with Silberstein (philosopher of physics) where he told me we had to restrict our talk to applications in QM because that's all the audience was interested in. Given that restriction, I fail to see the advantage of any interpretation over any other. Indeed, my adynamical interpretation of QM is unnecessarily deviant from intuition if all it's good for is interpreting QM. The reason I'm so pleased with it is precisely because I can use it to understand all of physics, even resolving controversies in classical physics, e.g., paradoxes of CTCs, dark matter, dark energy, horizon problem, etc. Sorry to prattle on, this is a pet peeve of mine :-)
     
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