> On 24 Feb 2020, at 23:12, Bruce Kellett <[email protected]> wrote: > > On Mon, Feb 24, 2020 at 11:29 PM Bruno Marchal <[email protected] > <mailto:[email protected]>> wrote: > On 23 Feb 2020, at 23:25, Bruce Kellett <[email protected] > <mailto:[email protected]>> wrote: >> On Mon, Feb 24, 2020 at 12:00 AM Bruno Marchal <[email protected] >> <mailto:[email protected]>> wrote: >> On 22 Feb 2020, at 05:37, Bruce Kellett <[email protected] >> <mailto:[email protected]>> wrote: >>> >>> I am not sure that I completely understand what Zurek has done here. The >>> problem of carrying the initial amplitdues through a sequence of repeated >>> trials is opaque to me. >> >> It seems to me that this is a direct consequence of the linearity of the >> tensor product. >> >> I interpret for example the 1/sqrt(2) in a superposition as describing an >> infinity of accessible histories, where I can access some particle state >> (and eigenvalue) with a probability one half. If I make a measurement, that >> “1/sqrt(2)” is inherited by the state describing me + that particle. >> >> I me> (1/sqrt(2) a + 1/sqrt(2) b) = 1/sqrt(2) Ime>Ia> + 1/sqrt(2) Ime>Ib>. >> The weigth of a has passed on me, by linearity/unitarity. >> >> Sure, you can write 1/sqrt(2) in front of each term. But the relative state >> in each case is the |me>, and that does not depend on the leading >> coefficient. > > Why? With such an interpretation, QM would not work. The relative > coefficients gives the superposition state that you are in. You could as well > say that there is no probabilities in the coin tossing, because each > “history” is independent of all the counterfactuals, but then there is no > more any probabilities at all, anywhere. > > QM works by imposing a probabilistic interpretation on these coefficients: > the Born rule is an additional assumption, it is not inherent in either > collapse theories or Everett many-worlds theories.
I am not entire sure about this. That is part of another debate. My position is that the Born rule can be justified from Gleason theorem, but I prefer to be sure you grasp the simpler self-multiplication before. > >> When you, in a single trial, see |up> (i.e., the state is |me, who sees >> up>), how does that depend on the 1/sqrt(2)? > > Because that 1/sqrt(2) told me in advance that once I consider the wave of me > + the particles, > > > In the 1p picture, you do not know the coefficient in advance -- you can only > infer probabilities from the data obtained in a sequence of trials. Let me explain why this does not work. Imagine that I change the protocol, without saying this to the candidate in Helsinki (to fix the thing). Indeed, I reconstitute him in Washington, Moscow and Sydney. The copy in Sydney will figure out immediately that he has been lied on the protocole. But the whole set of copies in W and in M will count themselves, and will see their experiences, collectively, as confining the binomial prediction, and we know that they are wrong. This illustrates that the probabilities cannot be inferred by the experiences alone, but only from the mechanist hypothesis + the knowledge of the protocole. Eventually, the “real protocol” is given later, and is only the (partially computable, sigma_1, arithmetical reality). > > belong to that superposition. It explains the probability that I observe, > including if I rotate my experimental device, by trotting differently the > mixture from the pure state. All use of probabilities are based on some > theories. The only problem for Everett is that once he uses mechanism, he has > to extract the wave itself from all computations realised in arithmetic (i.e. > *all* computations, with their complex redundancies, as we accept the > Church-Turing thesis). > >> From the first person perspective, remember -- do not mix in your 3p >> opinions. > > That is the whole problem: finding a 3p sharable description of the big > picture which explains the 1p local picture in a way which is coherent with > all the observers experiences and descriptions. > > > So you admit that you have to mix the 3p and 1p pictures. But in QM we only > have access to the 1p perspective. I don’t think that this make sense. We have also a 3p theory: QM. Without collapse, that theory is the given of the (universal or large enough to embed the observers) wave. We don’t have access to the theory in a direct experiential way, of course, we have it in mind when discussing about which probabilities can make sense or not. Bruno > > Bruce > > -- > 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLRO9_G_WG_d4W7uqqCcNuPB1q2qooO9S%3D_4sR1GwfnYXg%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLRO9_G_WG_d4W7uqqCcNuPB1q2qooO9S%3D_4sR1GwfnYXg%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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/78EDE7DA-BB5A-40E4-9FFA-87F3C5C52FA2%40ulb.ac.be.
