Monday, September 10, 2018

The Interpretation of Quantum Theory (again!) - Philip Ball

Amazon link

I'm into extreme diminishing returns on books about the interpretation of quantum theory. And here is another, only worth considering because Peter Woit has bothered reviewing it:
"Philip Ball’s Beyond Weird is the best popular survey I’ve seen of the contemporary state of discussions about the “interpretation” of quantum mechanics. ...

Instead of spending a lot of time in the rut of Bohmian mechanics, Ball dismisses it quickly as:
But it is hard to see where the gain lies… Even Einstein, who was certainly keen to win back objective reality from quantum theory’s apparent denial of it, found Bohm’s idea ‘too cheap.”
Dynamical collapse models like GRW also get short shrift:
It’s a bodge, really: the researchers just figured out what kind of mathematical function was needed to do this job, and grafted it on… What’s more of a problem is that there is absolutely no evidence that such an effect exists.
As for the “Many-Worlds Interpretation”, which in recent years has been promoted in many popular books, Ball devotes a full chapter to it, not because he thinks it solves any problem, but because he thinks it’s a misleading and empty idea:
My own view is that the problems with the MWI are overwhelming – not because they show it must be wrong, but because they render it incoherent. It simply cannot be articulated meaningfully… 

The MWI is an exuberant attempt to rescue the ‘yes/no’, albeit at the cost of admitting both of them at once. This results in an inchoate view of macroscopic reality suggests we really can’t make our macroscopic instincts the arbiter of the situation…

Where Copenhagen seems to keep insisting ‘no,no and no’, the MWI says ‘yes, yes and yes’. And in the end, if you say everything is true, you have said nothing.
There’s a lot of material about serious efforts to go beyond Copenhagen, by understanding the role that decoherence and the environment play in the emergence of classical phenomena out of the underlying quantum world. This discussion includes a good explanation of the work of Zurek and collaborators on this topic, including the concept of “Quantum Darwinism”. ... "
The comments on Woit's post are also interesting.

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For what it's worth (which is nothing) I suspect that we don't understand what the equations of quantum theory mean because we're still thinking in terms of the primacy of the 4D continuum. Starting from a more foundational space, ('spacetime is emergent'), quantum theory might just seem .. obvious.

Anyway, it's on my Kindle stack to look at later.

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Update: Here's the review/

2 comments:

  1. Your final conclusion may well be essentially correct, and it does raise the question as to whether this book covers QM from a General Relativity perspective, which forces a study of non-standard geometries at the foundations. If it is just a review of QM interpretations in standard geometries, then it may be all rather dull and familiar.

    All the same your Kindle stack may be so large that we will never hear of this book again!

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    Replies
    1. Already started it. It's grown up and doesn't talk down. I have hopes .. and Peter Woit's recommendation of course. I believe the author is going to pin his hopes on "it from bit" as per Witten's latest interest. That'll take some explaining.

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