4 ms·

Regular QM has non-locality. Entanglement is non-local, at least any way that I've heard it to explain things like delayed choice erasers and the behavior of en

Regular QM has non-locality. Entanglement is non-local, at least any way that I've heard it to explain things like delayed choice erasers and the behavior of entangled anyons in confined electron gases. (Anyons (particularly fused anyons) themselves seem to have nonlocal quantum vales assocaited with them.)

AgentME 10y ago
The many-worlds interpretation doesn't need non-locality.
- Jweb_Guru 10y ago
  Many-worlds still has nonlocal entanglement, IIRC, and all the weird phenomena therein.
  - DavidPlumpton 10y ago
    It does not require FTL signalling for the entanglement to work.
    - deleted 10y ago
      [deleted]
    - Jweb_Guru 10y ago
      Care to make rigorous how other interpretations require FTL signaling? For that matter, can you actually rigorously explain what it means for worlds to "branch", or why Born probabilities should be interpreted as though they are probabilities in MWI? Saying "all the possibilities actually happen!" doesn't really explain the correlations we actually observe in any interesting way.
      - effie 10y ago
        You make some good points. Regarding the Born probabilities, the extrapolation of Schroedinger equation to the whole universe seems to make the concept of probability superfluous and the Born rules lose their sense.
- cyphar 10y ago
  Bell's Theorem states that there exists no local hidden variable theory for QM. AFAIK that implies that QM must be non-local because the other possibilities of a local theory can be reduced to a hidden variable theory or have no evidence for them.
  - zeroer 10y ago
    Not true. Bell's result precludes local realism. So physics is either not local or lacks realism (counterfactual definiteness). The Many Worlds Interpretation keeps the locality but lacks counterfactual definiteness. The fact that MWI is the only interpretation that manages to hold onto both determinism and locality is what makes it so aesthetically pleasing.
codethief 10y ago
So we meet again, SomeStupidPoint. :) I still uphold my claim that regular QM is a local theory and just found time today to reply to your comment on non-locality that you posted a week ago: https://news.ycombinator.com/item?id=12936699 https://news.ycombinator.com/item?id=12936699 Let me know what you think!
- SomeStupidPoint 10y ago
  Hi there! I hadn't expected such a delayed reply! Will get to reading it this afternoon. (:

AgentME 10y ago

The many-worlds interpretation doesn't need non-locality.

Jweb_Guru 10y ago
Many-worlds still has nonlocal entanglement, IIRC, and all the weird phenomena therein.
- DavidPlumpton 10y ago
  It does not require FTL signalling for the entanglement to work.
  - deleted 10y ago
    [deleted]
  - Jweb_Guru 10y ago
    Care to make rigorous how other interpretations require FTL signaling? For that matter, can you actually rigorously explain what it means for worlds to "branch", or why Born probabilities should be interpreted as though they are probabilities in MWI? Saying "all the possibilities actually happen!" doesn't really explain the correlations we actually observe in any interesting way.
    - effie 10y ago
      You make some good points. Regarding the Born probabilities, the extrapolation of Schroedinger equation to the whole universe seems to make the concept of probability superfluous and the Born rules lose their sense.
cyphar 10y ago
Bell's Theorem states that there exists no local hidden variable theory for QM. AFAIK that implies that QM must be non-local because the other possibilities of a local theory can be reduced to a hidden variable theory or have no evidence for them.
- zeroer 10y ago
  Not true. Bell's result precludes local realism. So physics is either not local or lacks realism (counterfactual definiteness). The Many Worlds Interpretation keeps the locality but lacks counterfactual definiteness. The fact that MWI is the only interpretation that manages to hold onto both determinism and locality is what makes it so aesthetically pleasing.

codethief 10y ago

So we meet again, SomeStupidPoint. :) I still uphold my claim that regular QM is a local theory and just found time today to reply to your comment on non-locality that you posted a week ago: https://news.ycombinator.com/item?id=12936699 https://news.ycombinator.com/item?id=12936699 Let me know what you think!

SomeStupidPoint 10y ago
Hi there! I hadn't expected such a delayed reply! Will get to reading it this afternoon. (: