A couple of recent discussions about quantum mechanics that may be of interest:
- There’s a recent paper out by Don Weingarten that looks looks like it might have a different take on the fundamental “many-worlds” problem of, as he writes:
how in principle the definite positions of the macroscopic world emerge from the microscopic matter of which it is composed, which has only wave functions but not definite positions.
My naive feeling about this has always been that the answer should lie in a full understanding of the initial state of the measurement apparatus (+ environment), that it is our imperfect probabilistic understanding of the initial state that limits us to a probabilistic understanding of the final state. I found Weingarten’s investigation of this intriguing, although I’m not sure that the language of “hidden variables” is a good one here, given the use of that language in other kinds of proposals. By the way, Weingarten is an ex-lattice gauge theorist who I had the pleasure of first meeting long ago during his lattice gauge theory days. He at some point left physics to go work for a hedge fund, I believe he’s still in that business now.
Luckily for all of us, Jess Riedel has looked at the paper and written up some detailed Comments on Weingarten’s Preferred Branch, which I suggest that anyone interested in this topic look at. Discussion would best be at his blog, a much better informed source than this one.
- Gerard ‘t Hooft has a remarkable recent preprint about quantum mechanics, with the provocative title of Free Will in the Theory of Everything. I fear that the sort of argument he’s engaging in, trying to ground physics in very human intuitions about how the world should work, is not my cup of tea at all. Instead, what has always fascinated me about quantum mechanics has always been its grounding in very deep mathematical ideas, and the surprising way in which it challenges our conventional intuitions by telling us about an unexpected new way to think about physics at a fundamental level.
For more discussion of the paper, there are Facebook posts by Tim Maudlin here and here in which he argues with ‘t Hooft. I confess that I wasn’t so sure whether to take the time to read these, and after a short attempt gave up, unable to figure out precisely what the argument was about (and put off by Maudlin’s style of argument. Do philosophers really normally behave like that?). Links provided here in case you have more interest in this than I do, or better luck getting something out of it.