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Insights Interview with Astrophysicist: Adam Becker - Comments

  1. Mar 30, 2018 #21

    vanhees71

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    Maybe, there's a masochistic side in me :biggrin:
     
  2. Mar 30, 2018 #22

    fresh_42

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    Blame it on the heritage. :cool:
     
  3. Mar 30, 2018 #23

    Lord Jestocost

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    In the interview, Adam Becker says:

    What is Real? is about the unfinished quest for the meaning of quantum physics. We have this beautiful theory, quantum mechanics, and it’s astonishingly accurate. But it’s not at all clear what that theory is saying about the nature of the world around us. It must be saying something about that world—there must be something in nature that resembles the mathematics of quantum mechanics, otherwise why would the theory work so well? But there’s no clarity or consensus among physicists about what, exactly, quantum physics is saying about reality. This is very strange, especially given that quantum mechanics is over 90 years old.

    What is here very strange? It is strange that still today many try to squeeze something REAL out of the “quantum physics” tube. Quantum physics has nothing to say about the nature per se of the world around us. It’s about object-subject relations. And why should there be consensus among physicists? To ask “What, exactly, is quantum physics saying about reality?” is a biased question. It implicitly assumes – without trying to go to the bottom - that there is something like REALITY.

    In the interview, Adam Becker says:

    "The closest thing we have to a consensus about any of this is the Copenhagen interpretation. But the Copenhagen interpretation isn’t really a single coherent set of ideas about quantum mechanics—it’s a family of mutually-contradictory ideas, none of which adequately solve the measurement problem or answer the other questions at the heart of quantum theory. This is all the more strange given that reasonable alternatives to Copenhagen have existed for decades.

    What questions are at the heart of quantum theory? To my mind, such questions merely arise when people have the feeling that quantum theory “threatens” their personal psychological predispositions or philosophical beliefs. The “Copenhagens” were clearly aware of this.
     
  4. Mar 30, 2018 #24

    vanhees71

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    Quantum theory describes a tremendous part of the real world (or at least that part we can observe and objectively investigate, anyway). To say it's "not real" is simply rediculous. The word "real" is spoiled by philosophers to a degree that you cannot use it anymore in scientific discussions since its meaning has been put into the state of maximum entropy (mess) ;-)). SCNR.
     
  5. Mar 30, 2018 #25

    Lord Jestocost

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    To say that "quantum theory describes a tremendous part of the real world" is your personal "interpretation". That was my point.
     
  6. Mar 30, 2018 #26

    atyy

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    Copenhagen usually assumes the existence of reality. There is the classical/quantum cut, and the classical side (measurement outcomes) is reality. The terminology is bad, so one could also call the cut the macro/micro cut or the real/non-real cut.
     
  7. Mar 30, 2018 #27

    fresh_42

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    ... expressing it with a machine that relies on QM and is on the brink of a revolution, which will rely even more on it.
     
  8. Mar 30, 2018 #28

    vanhees71

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    No, it's a well-established fact by a plethora of high-accuracy measurements of all kinds of systems from the high-energy-particle experiments at the LHC over quantum optics, atomic, nuclear physics to condensed-matter physics. That's not simply a personal interpretation of a single physicist!
     
  9. Mar 30, 2018 #29

    vanhees71

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    The cut is also only in certain flavors of Copenhagen! There's no clear definition of it, and there's no known limit to the validity of quantum theory also for macroscopic systems. It's only a technical problem of state preparation preventing us from measuring "quantum properties" of macroscopic objects. In any case there are some empirical examples that prove the existence of predicted quantum effects like entanglement, as for example the experiment entangleling vibration modes of diamonds over some distance (working even at room temperature on a usual lab desk).
     
  10. Mar 30, 2018 #30
    One way to do something about this, vanhees71, is to ask for a manifestly Lorentz invariantly constructed random field that is equivalent to a quantum field. One finds that Einstein locality is indeed violated, but it's hard to object to a construction that is Lorentz invariantly constructed and that is equivalent to an empirically successful quantum field (specifically, quantized EM). I'll upload to here a current draft of a paper that derives from my EPL 87, 31002(2009) (the arXiv version is a couple of months old, as of now, and there's been lots of useful feedback from people on Facebook and from other correspondents since then; I intend to submit the paper to JMathPhys soon).
    Once one knows how, one can say that it's not so hard.
    I gotta say that I think philosophy does something more than nothing for physics, though as in anything there's a lot that doesn't do much for me.
     

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  11. Mar 30, 2018 #31

    atyy

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    The cut is in all flavours of Copenhagen.

    True, the cut is subjective.

    True, the cut can be shifted, so anything can be moved from the classical side of the cut to the quantum side of the cut.

    However, you cannot put the whole universe, including all observers on the quantum side of the cut, with nothing left on the classical side. People try to do so, but that requires an attempted solution to the measurement problem, eg. Many Worlds or Bohmian Mechanics.
     
  12. Mar 31, 2018 #32

    zonde

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    This is strawman attack. Philosophy is not rival to physics. Philosophy of science is concerned about physics solutions rather than physics problems.
    It is interesting that the author of Statistical interpretation clearly differentiates his interpretation from Copenhagen and describes it the way that can be viewed as generic HV interpretation (wavefunction is not a complete description of individual system).
     
    Last edited: Mar 31, 2018
  13. Mar 31, 2018 #33

    Lord Jestocost

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    Henry P. Stapp in “The Mindful Universe”:

    In the introduction to his book Quantum Theory and Reality the philosopher of science Mario Bunge (1967, p. 4) said:

    The physicist of the latest generation is operationalist all right, but usually he does not know, and refuses to believe, that the original Copenhagen interpretation – which he thinks he supports – was squarely subjectivist, i.e., nonphysical.

    Let there be no doubt about this point. The original form of quantum theory is subjective, in the sense that it is forthrightly about relationships among conscious human experiences, and it expressly recommends to scientists that they resist the temptation to try to understand the reality responsible for the correlations between our experiences that the theory correctly describes.


    The confusion arises when one begins to reason about “the experience of WHAT” - maybe, you can call the "WHAT" the "REALITY" in a metaphysical sense. Quantum theory is – so to speak - about that what’s in our head, the varying content of our consciousness. It has nothing to say about the WHAT. The WHAT is of inscrutable nature. And the tremendous fallacy to mistake the map – the content of our conscious – with the territory - the WHAT - leads to pseudo-questions at the heart of quantum theory.
     
    Last edited: Mar 31, 2018
  14. Mar 31, 2018 #34

    atyy

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    As Bell said, presumably, you do not buy life insurance.
     
  15. Mar 31, 2018 #35

    vanhees71

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    Well, then you'd call the minimal interpretation not a Copenhagen flavor. Fine with with me, although I don't think that it is too much different from what's presented as "Copenhagen Interpretation" in standard textbooks. For me the minimal interpretation is mostly this "Copenhagen Interpretation" omitting the collapse (which is not needed and almost never realized in experiments, except it's necessary to take the effort to do so) and the classical-quantum cut, which is anyway not clearly defined as you agree about above. If you call to put a "classically" behaving macroscopic measurement device a "cut", it's just strange language, and that macroscopic measurement devices behave classically for me is rather explained by decoherence than by some fundamental quantum-classical cut.
     
  16. Mar 31, 2018 #36

    vanhees71

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    My criticism against philosophy in QT is not that it doesn't solve any problems, but that they pretend that there are problems, where there are none and then confusing the subject by unclear definitions of prime notions like "reality". Thanks to philosophy (starting with the unfortunate EPR paper, which according to Einstein has not brought out his main concerns with QT which was more about inseparability due to entanglement, as he wrote in his Dialectica article of 1948 [*]) the word "reality" has almost lost its usability, because it is not clear anymore what exactly an author using it wants to say ;-)).

    [*] A. Einstein, Quanten-Mechanik und Wirklichkeit, Dialectica 2, 320 (1948)
    https://doi.org/10.1111/j.1746-8361.1948.tb00704.x

    Who is "the author"? Please try to cite clearly; if possible, I guess many in the forums appreciate also a link to a legal source of the paper.
     
  17. Mar 31, 2018 #37

    Demystifier

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    Scientific method can solve some problems, but scientific method, by itself, cannot determine what is a problem and what is not. Your criticism against philosophy in QT is a philosophy itself.
     
  18. Mar 31, 2018 #38
    So, going back to your earlier comment,
    do you consider that whatever nonlocality there is in QM/QFT is not a problem? Of course microcausality is satisfied, so there is not that kind of nonlocality, but still there is, say, Hegerfeldt nonlocality (for references relevant to that, please see https://www.facebook.com/max.derakshani/posts/10103068335632754?comment_id=10103069043593994 and the comments that follow). Personally, I agree that the modern focus of philosophers specifically on "reality", whatever that means beyond hammering the desk, is perhaps excessive — I prefer a rather heavier dose of empiricism and calibrated acceptance of current theories.
     
  19. Mar 31, 2018 #39

    Demystifier

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    Many great physicists turn into philosophers later. Maybe you are getting old. :biggrin:
     
  20. Mar 31, 2018 #40

    vanhees71

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    Well, in physics there are a lot of problems determined within physics itself and some are solved and some are unsolved. That there is a "measurement problem" in QT for me is disproven by evidence since experimentalists and theorists can very well design and analyze experiments using QT. If this is philosophy, that's fine with me ;-))).
     
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