On Sunday, November 26, 2017 at 8:29:22 AM UTC-6, Bruno Marchal wrote: > > > On 24 Nov 2017, at 15:59, Lawrence Crowell wrote: > > On Thursday, November 23, 2017 at 5:53:14 PM UTC-6, Bruce wrote: >> >> On 24/11/2017 10:15 am, Lawrence Crowell wrote: >> >> On Wednesday, November 22, 2017 at 9:37:48 AM UTC-6, Bruno Marchal wrote: >>> >>> >>> On 20 Nov 2017, at 23:04, Bruce Kellett wrote: >>> >>> >>> You clearly have not grasped the implications of my argument. The idea >>> that "MWI replaces all nonsensical weirdness by one fact (many histories)" >>> does not work, and is not really an explanation at all -- you are simply >>> evading the issue. >>> >>> >>> Without collapse, the apparent correlations are explained by the linear >>> evolution, and the linear tensor products only. I have not yet seen one >>> proof that some action at a distance are at play in quantum mechanics, >>> although I agree that would be the case if the outcome where unique, as >>> EPER/BELL show convincingly. >>> >>> Aspect experience was a shock for many, because they find action at a >>> distance astonishing, but are unaware of the many-worlds, or just want to >>> dismiss it directly as pure science fiction. But after Aspect, the choice >>> is really between deterministic and local QM + many worlds, or one world >>> and 3p indeterminacy and non locality. Like Maudlin said, choose your >>> poison. >>> >>> >>> Bruno >>> >>> Bruce >>> >>> >> I am new to this list and have not followed all the arguments here. In >> weighing in here I might be making an error of not addressing things >> properly. >> >> Consider quantum entanglements, say the entanglements of two spin 1/2 >> particles. In the singlet state |+>|-> + |->|+> we really do not have the >> two spin particles. The entanglement state is all that is identifiable. The >> degrees of freedom for the two spins are replaced with those of the >> entanglement state. It really makes no sense to talk about the individual >> spin particles existing. If the observer makes a measurement that results >> in a measurement the entanglement state is "violently" lost, the >> entanglement phase is transmitted to the needle states of the apparatus, >> and the individual spin degrees of freedom replace the entanglement. >> >> We have some trouble understanding this, for the decoherence of the >> entangled state occurs with that state as a "unit;" it is blind to any idea >> there is some "geography" associated with the individual spins. There in >> fact really is no such thing as the individual spins. The loss of the >> entangled state replaces that with the two spin states. Since there is no >> "metric" specifying where the spins are before the measurement there is no >> sense to ideas of any causal action that ties the two resulting spins. >> >> This chaffs our idea of physical causality, but this is because we are >> thinking in classical terms. There are two ways of thinking about our >> problem with understanding whether quantum mechanics is ontic or epistemic. >> It could be that we are a bit like dogs with respect to the quantum world. >> I have several dogs and one thing that is clear is they do not understand >> spatial relationships well; they get leashes and chains all tangled up and >> if they get wrapped up around a pole they simply can't figure out how to >> get out of it. In this sense we human are simply limited in brain power and >> will never be able to understand QM in some way that has a completeness >> with respect to causality, reality and nonlocality. There is also a far >> more radical possibility. It is that a measurement of a quantum system is >> ultimately a set of quantum states that are encoding information about >> quantum states. This is the a quantum form of Turing's Universal Turing >> Machine that emulates other Turing machines, or a sort of Goedel >> self-referential process. If this is the case we may be faced with the >> prospect there can't ever be a complete understanding of the ontic and >> epistemic nature of quantum mechanics. It is in some sense not knowable by >> any axiomatic structure. >> >> >> Hi Lawrence, and welcome to the 'everything' list. I have come here to >> avoid the endless politics on the 'avoid' list. >> The issue that we have been discussing with EPR pairs is whether many >> worlds avoids the implications of Bell's theorem, so that a purely local >> understanding of EPR is available in Everettian models. I have argued that >> this is not the case -- that non-locality is inherent in the entangled >> singlet state, and many worlds does not avoid this non-locality. I think >> from what you say above that you might well agree with this position. >> >> Bruce >> > > Of course MWI can do nothing of the sort. MWI suffers from much the same > problem all quantum interpretations suffer from. > > > I don't see this. the MW theory (that is the WWE without the collapse > axiom) explains the violation of inequality in a way which avoids any > action at a distance, but when we assume one universe, like Einstein > explains very clearly already in 1927, you get a notion of simultaneousness > incompatible with special relativity and very minimal form of realism. > > For me, as a logician, I consider that SWE and SWE+collapse are different > theories. The first is local, deterministic and admits a local physical > realism, the second is not intelligible at all, as the notion of observer > is unclear and dualistic. > > Bruno >
I suppose I don't know what WWE means. MWI is not a bad idea, but I frankly question whether it along with all other interpretations are properly scientific theories. I see no particular way that any quantum interpretation can be tested. The idea is nice in that it gives an idea of a total universe as unitary, but where the phenomenology has us moving along one particular path in a decoherence event. However, if we are to have a splitting off of the world we might think of there being a many block world perspective, where a decoherence of a quantum event splits off quantum amplitudes on all possible spatial surfaces that contain this event. This has been referred to in the past as the gemische; all possible spacelike manifolds that embed a measurement event. However, we have some ambiguity with respect to probability amplitudes associated with each path in this splitting. LC -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
