Issues in QM Foundations?

  • #26
721
507
You may hold the opinion that only a non-local theory can explain entanglement, but that is just an opinion - and it is hardly consensus in the community.
How about this paper:
Coecke et al. 2010, Phase groups and the origin of non-locality for qubits
Abstract said:
We describe a general framework in which we can precisely compare the structures of quantum-like theories which may initially be formulated in quite different mathematical terms. We then use this framework to compare two theories: quantum mechanics restricted to qubit stabiliser states and operations, and Spekkens's toy theory. We discover that viewed within our framework these theories are very similar, but differ in one key aspect - a four element group we term the phase group which emerges naturally within our framework. In the case of the stabiliser theory this group is Z4 while for Spekkens's toy theory the group is Z2 x Z2. We further show that the structure of this group is intimately involved in a key physical difference between the theories: whether or not they can be modelled by a local hidden variable theory. This is done by establishing a connection between the phase group, and an abstract notion of GHZ state correlations. We go on to formulate precisely how the stabiliser theory and toy theory are `similar' by defining a notion of `mutually unbiased qubit theory', noting that all such theories have four element phase groups. Since Z4 and Z2 x Z2 are the only such groups we conclude that the GHZ correlations in this type of theory can only take two forms, exactly those appearing in the stabiliser theory and in Spekkens's toy theory. The results point at a classification of local/non-local behaviours by finite Abelian groups, extending beyond qubits to finitary theories whose observables are all mutually unbiased.
 
  • #27
DrChinese
Science Advisor
Gold Member
7,332
1,140
Seriously, this makes no sense at all. I read 50 of these a month, and this has essentially nothing to do with what we are discussing. You're talking casually about re-interpreting one of the most important discoveries in quantum mechanics in the last 50+ years, as Bell is basically a disproof of EPR. And you are trying to make an argument which is accepted by no one who is anyone. Right or wrong, that is a point of view which would require a massive change of consensus, and certainly no one who has read these papers has had the epiphany you have had.

I have had endless discussions on this exact topic with Norsen, and the only people who have any interest in his (and Durr's) perspective on this subject is committed Bohmians. So please, stop now before we take this any further. PhysicsForums is not the place for people trying to change the physics community. It is a place to learn about accepted physics. Discussion with suitable caveats is one thing, but you have jumped into the realm of pointed speculation with a lack of proper labeling. That's not right.
 
  • Like
Likes weirdoguy
  • #28
DrChinese
Science Advisor
Gold Member
7,332
1,140
... I find much of what Peres says very sensible.

In any case, what about their arguments? Surely, the arguments stand on their own merits. ...
Quote Peres then. Not sure I follow your thinking, as he was a believer in QM as a contextual theory.

But no, the arguments don't stand on the merits. What are we going to do, vote on those? :smile:
 
  • #29
1,184
349
Dear @DrChinese, exactly what proposition are you so vehemently criticizing? I seriously can't tell. Wikipedia says local physics can't reproduce quantum mechanics, and you approve; @Auto-Didact says various things, e.g. "the world is non-local", and you strongly disapprove. What nuance should I be noticing?
 
  • Like
Likes Auto-Didact
  • #30
DrChinese
Science Advisor
Gold Member
7,332
1,140
Dear @DrChinese, exactly what proposition are you so vehemently criticizing? I seriously can't tell. Wikipedia says local physics can't reproduce quantum mechanics, and you approve; @Auto-Didact says various things, e.g. "the world is non-local", and you strongly disapprove. What nuance should I be noticing?
The world is *not* local realistic. Note the word "realistic", which is sometimes replaced by "hidden variables", "non-contextual", "objective", "observer independent", etc.

Some Bohmians (I am not accusing anyone) try to push the idea that Bell proves there is non-local action, which would then seem to point to it (Bohmian Mechanics) as the only viable interpretation. My objection is not that the argument is made, but it is made in this thread without suitable labeling as speculative. Note that I am not saying Bohmian Mechanics is anymore speculative itself than any other interpretation.

I am well familiar with the arguments Auto-Didact is making, and of course would be able to argue against that. But that would have the effect of perpetuating a false debate, because I would have the burden of refuting something that is flat out incorrect. That being the statement that Bell disproves locality. Bell essentially disproves local realism, if you assume QM's predictions are correct.

Who knows, in 10 years Auto-Didact might be in the majority view. For this forum, at this time, that view is not accepted and arguments supporting it should not be presented EXCEPT in a thread dedicated to discussing Durr's paper. This isn't that.
 
  • #32
PeterDonis
Mentor
Insights Author
2019 Award
30,058
9,244
After review, the thread will remain closed. The topic of the thread is not whether the claims of Durr et al. in the paper cited are correct, but "is there an issue with QM foundations". Since the latter is a matter of opinion, it's not really a good thread topic, but in any case, enough opinions have been expressed for the topic to be reasonably covered at this point.
 
  • Like
Likes bhobba, DrChinese and DrClaude

Related Threads on Issues in QM Foundations?

  • Last Post
Replies
15
Views
2K
Replies
1
Views
206
Replies
57
Views
9K
  • Last Post
Replies
4
Views
1K
Replies
14
Views
3K
Replies
4
Views
3K
Top