On Tue, Apr 19, 2022 at 11:09 AM Brent Meeker <meeke...@gmail.com> wrote:
> The only purpose of the box in Schroedinger's thought experiment was to >> put off the observers perception. Really the thought experiment is over >> when the radioactive decay occurs. That atom has transitioned to a >> different nuclear state which is entangled with and recorded in the >> environment. >> > On Tuesday, April 19, 2022 at 4:20:49 AM UTC+3 Bruce wrote: > Yes. Schrodinger had the cat in a box to emphasize the idea that the cat > was in a macro-superposition of alive/dead. This misled Wigner to the > extent that he thought the state collapsed only when the box was opened. > All of this was made redundant when it was realized that decoherence > rendered the state definite almost instantaneously. Saibal makes the same > mistake when he claims that Alice, after her measurement, is still in a > superposition until Bob sees her result. The idea that the superposition > still exists since decoherence is only FAPP is something of a red herring > -- in MWI, Alice has branched according to her result into up and down > branches that no longer interfere. There is no macro-superposition. > -1- Decoherence (by a chaotic environment) turns an entangled superposition into a non-coherent density matrix, only if we subsequently omit the environment from the description of the system. (Not if we keep the environment in the description.) -2- The "box" (in which Scroedinger's cat is enclosed, with the lethal apparatus) contains also its "environment", so a quantum descrition of this box describes the environment also. Therefore I do not agree that decoherence INSIDE THE BOX will ruin the superposition ASSESSED FROM OUTSIDE THE BOX. So, Wigner was right. I suppose that Saibal also is right, though I have not checked that message (sorry). I rephrase my conclusion. I agree with you, on the splits being technically non-local, but this is only an artifact of describing the dynamical evolution of the wavefunction in space-like slices forming a time-like stack. Thus a split affects the whole slice in which it occurs. But seen from a moving train, it would be a different slice! Only on and inside the light cone, the split is physically meaningful. Thanks to your insistence, now I see the difference between non-local HV theories, which violate relativity, and MWI, which does not. I am writing in a hurry, because these days are hectic. I may have missed some important postings, sorry. I would welcome any hints (with the name and time of posting) sent to my G-mailbox: GeKahrim. George K. -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/37de846e-9d01-479e-b8ea-a07c519bfcc6n%40googlegroups.com.
