On Friday, October 28, 2022 at 11:24:40 PM UTC-5 Bruce wrote: > On Sat, Oct 29, 2022 at 3:21 PM Brent Meeker <[email protected]> wrote: > >> I agree with that, since I think collapse or probability is necessary for >> the theory to work. But I regard it all as one unified theory. As Omnes >> writes, "QM is a probabilistic theory. So it predicts probabilities." >> > > The problem is that MWI is not a probabilistic theory, so it can't be all > of QM. > > Bruce >
Why is MWI not probabilistic? It is an interpretation of quantum amplitudes. It states that in a decoherence event the paths for particular probabilities, say the diagonal of the density matrix, are "globally" a part of a superposed or entangled set, but that "locally" only one outcome occurs and so the world splits. I am not sure why this violates probability. Decoherence attenuates the off diagonal quantum phase terms of the density matrix, and a density matrix reduced to diagonal form means that at this point the collapse is a sort of "classical collapse." One possible objection to MWI might be how can a classical outcome of probabilities then have this splitting off of quantum worlds? There is a funny meaning to the world as nonlocal in some bird's eye perspective, but local from the frog's eye perspective, where the frog perceives itself as "quantum frame dragged" along a particular quantum path. MWI plays with nonlocality in a strange way. The splitting of worlds, say Alice and Bob looking at their Stern-Gerlach apparatus. We have the Einstein glove issue if Alice and Bob both measure in the z-direction. However, if Alice measures along the z-axis and then Bob measures along the x axis, or somewhere in the x-z plane, these two measurements are independent. Alice's measurement has no dependency on what Bob's measurement is, Bell's inequality violation, and Bob must measure independently. Yet, MWI has a global splitting of worlds, and here we see the outcome is not reduced by a local measurement. MWI has this added feature of nonlocal property with how worlds split apart. 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/30bbac03-7b45-4a80-a420-19c50226b131n%40googlegroups.com.
