> On 10 Feb 2020, at 08:17, Bruce Kellett <bhkellet...@gmail.com> wrote: > > On Mon, Feb 10, 2020 at 5:08 PM smitra <smi...@zonnet.nl > <mailto:smi...@zonnet.nl>> wrote: > On 09-02-2020 11:37, Bruce Kellett wrote: > > On Sun, Feb 9, 2020 at 7:48 PM smitra <smi...@zonnet.nl > > <mailto:smi...@zonnet.nl>> wrote: > > > >> On 08-02-2020 07:00, Bruce Kellett wrote: > >>> On Sat, Feb 8, 2020 at 4:21 PM smitra <smi...@zonnet.nl > >>> <mailto:smi...@zonnet.nl>> wrote: > >>> > >>>> On 08-02-2020 05:19, Bruce Kellett wrote: > >>>> > >>>>> No, I am suggesting that Many-worlds is a failed theory, unable > >> to > >>>>> account for everyday experience. A stochastic single-world > >> theory > >>>> is > >>>>> perfectly able to account for what we see. > >>>>> > >>>>> Bruce > >>>> > >>>> Stochastic single word theories make predictions that violate > >> those > >>>> of > >>>> quantum mechanics. > >>> > >>> No they don't. When have violations of the quantum predictions > >> been > >>> observed? > >> > >> A single world theory must violate unitary time evolution, it has to > >> > >> assume a violation of the Schrodinger equation. But there is no > >> experimental evidence for violations of the Schrodinger equation. > >> While > >> one can make such assumptions and develop a formalism based on this, > >> the > >> issue is then that in the absence of experimental proof that the > >> Schrodinger equation is going to be violated, one should not claim > >> that > >> such a model is superior than another model that doesn't imply any > >> new > >> physics. > > > > So what. If Everettian QM doesn't work, as it has been shown to fail > > in that is does not recover normal scientific practice, then one must > > look to alternative theories. I have not advocated any particular > > theory, but a break down of unitary evolution is not such a big deal > > -- it is what we observe every day, after all. This is the heart of > > the quantum measurement problem. > > The focus on Everettian QM to argue against MWI in general is a straw > man attack. > > That would not be the way most physicists would see it. They take Everettian > QM as basic. Unfortunately, Everettian QM has hit a catastrophic train wreck > -- it is clearly not viable as an understanding of quantum physics. The > reason for this is a clear corollary of Kent's argument. Simply put, Everett > takes the Schrodinger equation as basic. Acting on a general quantum state > with the Schrodinger equation gives the relative states, and there can only > ever be one relative state for each term in the expansion in terms of some > set of basis states. The amplitudes of interest are the coefficients in this > expansion. However, these coefficients or amplitudes, are just ordinary > complex numbers, so are completely transparent to the SE. The set of > sequences of outcomes of repeated trials (measurements on replications of the > initial state) is then all n^N sequences of outcomes (labelled by 0 - n-1 for > the n possible outcomes for N trials). This set of sequences is independent > of the amplitudes in the original expansion of the state of interest in terms > of the set of basis states. Consequently, the data one obtains from this set > of experiments is one of the set of possible sequences of the integers 0 to > n-1, is completely independent of the amplitudes in the original expansion. > One can, therefore, gain no information about these amplitudes from the set > of N trials. The Born rule is irrelevant, because the data are necessarily > independent of the coefficients/amplitude. > > This proves that Everett's approach from the SE, where there is only one > branch for each possible outcome in a single trial, cannot account for the > way in which experimental results are used in practice. Given Everett, > experiments cannot reveal anything at all about the original state. So > Everett fails as a scientific theory. End of story. Period. Nothing more to > be said. > > > The main issue is unitary time evolution. This is a rather > unambiguous thing that one can check in experiments. A breakdown of > unitary time evolution has never been observed. > > As Brent has pointed out, unitary evolution breaks down every time we observe > a particular result for a measurement (to say nothing of black holes). Your > focus on unitary evolution is misplaced -- it is not universally observed.
“Unitary evolution” is the theory, which has not an observable in any reasonable sense of observable. To add a collapse is like saying that theory break down, but there no observation indicating that it does, given that the theory explains, or is supposed to explain, such an appearance. What you seem to say is that QM might be wrong, but to assume a theory is wrong to satisfy an ontological commitment is not in “the normal scientific practice” (as you said). > > Many-worlds theory might be salvageable from the train wreck of Everett, but > it is not clear how. It seems to be widely assumed that there is more than > one branch for each basis state, even though that is not what Everett or the > SE say. It is not clear how this could ever happen in a principled way: it > certainly is not consistent with unitary evolution via the Schrodinger > equation. On the contrary, Everett is the only one entirely consistent with unitary evolution, and that is why cosmologist refers to it, when they are confronted to the problem that the Copenhagen have necessarily when applying QM to the whole universe, or to just a portion we inhabit. Everett’s idea is just an idea already defended by Newton which is that the physicists obeys to the physical law; and Everett has just realised that most paradox get away when we apply the SWE to the couple observed - observer. That leads to a complicated counter-intuitive ontology, but eventually, as Everett used Mechanism, we know that eventually any simple Turing universal ontology will do. Bruno > There may be a way out of this, but none has been offered to date, and I > would not hold out many prospects for success in such venture. > > 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 everything-list+unsubscr...@googlegroups.com > <mailto:everything-list+unsubscr...@googlegroups.com>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLQG5ugE-ZDqPRomr7VCsRi00yP8wVrXYMoRgeFgXha%3D4w%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLQG5ugE-ZDqPRomr7VCsRi00yP8wVrXYMoRgeFgXha%3D4w%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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/6057D8E5-948B-4060-8472-A319C99A5A56%40ulb.ac.be.
