Why is quantum mechanics non-local? (I wish someone had told me this 20 years ago.)She correctly says that a lot of people say quantum mechanics is nonlocal, but by that, they mean that the wave function collapse is nonlocal. That is true, but not a physical nonlocality, she correctly says.
She also correctly says that last year's Nobel Prize for Bell test experiments did not endorse any nonlocality, even though some reported it that way.
Those experiments are consistent with:
- Quantum mechanics, non-classical, local, Copenhagen
- Nonlocal theories of hidden variables
- Superdeterminism
- Retrocausality
- Many-worlds
The only possibility ruled out by Bell tests is a local theory of classical hidden variables.
Hossenfelder like superdeterminism, which in this video she calls "Violation of measurement independence". It means you can never randomize the inputs to an experiment, so you can never trust the outputs.
She prefers superdeterminism to nonlocal theories of hidden variables. She acts as if those are the only two possibilities. However both have been rejected by almost everyone. It is a silly preference.
I only post this because her podcasts get a lot of views, and people think that they are learning something. But she has fringe views that are contrary to almost all of modern science.
Mathematicians like all sorts of things that make their calculations easier...even if they have nothing to actually do with reality.
ReplyDeleteThe 'wave function collapsing' has nothing to do with reality. It has to do with the calculation of math, and the entire conceptual idea of probabilities having external existence outside of the imagination of whoever calculated them. There is no 'wave' there to collapse, only numbers. Probabilities are just second hand calculations as well, utterly dependent for their existence upon taken measurements and their attendant accuracy which are then overlayed like an imaginary grid upon an actual situation they are supposed to model. This is really no different than saying 'one sheep, two sheep, three sheep'..... ok, I've got three sheep...but if I just change the word variable *sheep*, I now have three dollars, or oranges, or stupid mathematicians. But is this actually true? That depends on a whole slew of other assumptions that may or may not be true (or outside someone's imagination), and that are probably not included in the math at all.
Dear Roger,
ReplyDeleteYou say:
> ``The latter four possibilities do not make any physical sense, but are mathematically possible...''
I would say that even a *mathematically* consistent theory that has an ontologically complete basis in the physical world, would be impossible to have, in respect of each of those four proposals --- and for many other proposals too. (The last time I checked, the Wiki on QM Interpretations had listed some *17* of them.)
People who propose such ideas (or talk about such proposals) don't offer (i) ontological basis, and (ii) completeness of description. ... Why, sometimes they don't even care for: (iii) only the physical reality as the ultimate referent for a theory of physics.
If consciousness-induced collapse theories disregard the requirement number (iii), Superdeterminism disregards the requirement number (ii), not to mention also (i).
If only a certain auxiliary data can make a theory workable, then that theory is not at all general, and hence, it cannot at all qualify as a theory in the first place. The ``theory,'' in such cases, reduces merely to a convenient tool for processing of a certain *concrete* signal. In the case of Superdeterminism, the special auxiliary data so required pertain to the initial condition of the entire universe --- with the meaning of that phrase itself not spelt out (can there be an IC for the whole universe?).
---
Crucial to the experiments behind the last year's Nobel were photons, not electrons. I suspect (though won't soon publish details of my thoughts) that certain fundamentals regarding the respective mechanisms for measurements might be different in the two cases (photons vs. electrons).
I should take at least a few months to get a minimal grasp on Dirac's equation. I shall address the preceding issue after that.
Best,
--Ajit