> On 3 May 2018, at 17:28, 'scerir' via Everything List > <[email protected]> wrote: > > > > >> Il 3 maggio 2018 alle 16.28 Bruno Marchal <[email protected]> ha scritto: >> >> >>> On 1 May 2018, at 18:13, 'scerir' via Everything List < >>> [email protected] <mailto:[email protected]>> >>> wrote: >>> >>> >>> >>> >>>> Il 1 maggio 2018 alle 17.36 Bruno Marchal < [email protected] >>>> <mailto:[email protected]>> ha scritto: >>>> >>>> >>>>> On 29 Apr 2018, at 08:21, 'scerir' via Everything List < >>>>> [email protected] >>>>> <mailto:[email protected]>> wrote: >>>>> >>>>> IMO Schroedinger invented this manyworlds or manyminds or manywords >>>>> interpretation. >>>>> >>>> >>>> The quote below seems to indicate that this is not the case, unless you >>>> agree (with me, and Deutsch, …) that QM *is* the discovery of the many >>>> superposed worlds/states/minds, and that the founder added the collapse >>>> postulate ONLY to avoid the proliferation of the alternate >>>> worlds/states/minds. >>> >>> Yes, I can agree with that. But it is possible there was, in those years, >>> another issue too. I mean conservation of energy. It is not possible, in >>> general, to preserve conservation of energy in each universe during the >>> split-decoherence, especially in case of superposition of states of >>> different energy. In this special case energy increase in one universe and >>> decrease in another universe. >>> >> >> The conservation of energy seems to me to be a classical, and mainly >> statistical notion. I do not see why the many-universes would violate >> thermodynamics in any branches, given that, by linearity of evolution, each >> branch evolves independently of the others, and the branches can only >> interfere, statistically, from the first person perspective of the observer. >> I am not even sure how we could superpose two states with different energy. >> May be you could explain me this. >> >> Bruno > > The worlds are not autonomous during the split (decoherence process) of the > original unique world. > >
By linearity, I don’t see that possible. The worlds can interfere but cannot interact. We can’t steal the petrol in a parallel worlds. The statistical conservation of energy in each worlds seems to me to follow from unitary evolution. > "Now, there isn't really a story to tell about what the total energy in > individual universes is during that whole process [of measurement]. Because > the universes are not autonomous during it. > I guess Deutsch alludes to the fact that they can interfere, on they non distinguishable parts. > But one thing's for sure, there is no way of construing it so that the energy > in each particular universe is conserved, for the simple reason that the > whole system starts out the same on each run of the experiment (before the > non-sharp state is created), and ends up different". --David Deutsch > > Different from the observer’s point of view. That is correct; they got some bit of information, but that is the case for all measurement. Taken literally, what Deutsch says here would be a problem for the “Zurek” quantum solution of the Maxwell Daemon paradox, based on Landauer discovery that in a computation, only erasing information needs energy. > In a superposition of states of different energy I am inclined to think > (naively) that the energy of the superposition state lies in between the > energy of its constituents. Actually the theory only states there are > expectation values, that is to say what you get if you perform many > measurements, and then you average. Now the measurement process itself is an > "interaction" with the superposition state, and I do not know whether this > interaction, in the MWI, is unitary or not. > It is unitary in the third person perspective on the “whole wave”, and it is not unitary from the first person view, which live (but only live, subjectively) the experience of the collapse. > "In more general cases, where there are superpositions of states of different > energy, energy can increase in one universe at the cost of decreasing in > another." --David Deutsch > > Perhaps. I am not sure. > But let us read Hartle here https://arxiv.org/abs/gr-qc/9410006 > <https://arxiv.org/abs/gr-qc/9410006> > http://blog.jessriedel.com/2015/08/23/how-to-think-about-quantum-mechanics-part-6-energy-conservation-and-wavefunction-branches/ > > I remember having read that paper a long time ago I might reread it, but I am not sure I disagree with any of it. Bruno > . > >> >> >>>> Everett is just the guy who realise that the MW does not leads to a jelly >>>> quagmire of everything, by taking the first person view (what he called >>>> subjective) of the observers, as their memories get as much quasi >>>> orthogonal that the results they could have attributed to a collapse. The >>>> collapse, and the irreversibility is purely “subjective” (first person) >>>> and irreversible in principle for *us*. To reverse the entire universal >>>> wave, we would need to go outside the physical universe in some practical >>>> way, which, needless to say, is rather difficult. >>>> >>>> But I do agree with you, Schroedinger and Einstein understood that the >>>> collapse was a problem for the rest of physics and philosophy. They were >>>> rightly skeptical that Bohr and Heisenberg got the whole thing. Would have >>>> they like Everett? Bohr just threw Everett out of his home, I have read >>>> somewhere. I think Einstein would have prefer it to anything involving an >>>> action at a distance, like Bohm’s theory (non local hidden variable >>>> theory). Indeed, as you all know, Einstein told that he would have >>>> prefered to be a plumber than be involved in a theory with some >>>> action-at-a distance. >>>> >>>> Bruno >>>> >>>> >>>> >>>> >>>>>> Il 28 aprile 2018 alle 23.01 [email protected] >>>>>> <mailto:[email protected]> ha scritto: >>>>>> >>>>>> >>>>>> >>>>>> On Saturday, April 28, 2018 at 5:55:16 AM UTC, scerir wrote: >>>>>> >>>>>> >>>>>> >>>>>>> I think Schroedinger and his cat bear some responsibility. In trying >>>>>>> to debunk Born's probabilistic interpretation he appealed to the >>>>>>> absurdity of observation changing the physical state...even though no >>>>>>> one had actually proposed that. >>>>>>> >>>>>>> Brent >>>>>>> >>>>>> >>>>>> “The idea that the alternate measurement outcomes be not alternatives >>>>>> but all really happening simultaneously seems lunatic to the quantum >>>>>> theorist, just impossible. He thinks that if the laws of nature took >>>>>> this form for, let me say, a quarter of an hour, we should find our >>>>>> surroundings rapidly turning into a quagmire, a sort of a featureless >>>>>> jelly or plasma, all contours becoming blurred, we ourselves probably >>>>>> becoming jelly fish. It is strange that he should believe this. For I >>>>>> understand he grants that unobserved nature does behave this way – >>>>>> namely according to the wave equation. . . . according to the quantum >>>>>> theorist, nature is prevented from rapid jellification only by our >>>>>> perceiving or observing it.” >>>>>> >>>>>> -Erwin Schroedinger, The Interpretation of Quantum Mechanics. Dublin >>>>>> Seminars (1949-1955) and Other Unpublished Assays (Ox Bow Press, >>>>>> Woodbridge, Connecticut, 1995). >>>>>> >>>>>> >>>>>> Who is Schrodinger referring to? This was written before 1957, when >>>>>> Everett published his MWI.? Were other theorists advancing the idea that >>>>>> all alternatives are physically manifested in reality? AG >>>>>> >>>>>> >>>>>> -- >>>>>> 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 post to this group, send email to [email protected] >>>>>> <mailto:[email protected]>. >>>>>> Visit this group at https://groups.google.com/group/everything-list >>>>>> <https://groups.google.com/group/everything-list>. >>>>>> For more options, visit https://groups.google.com/d/optout >>>>>> <https://groups.google.com/d/optout>. >>>>> >>>>> >>>>> -- >>>>> 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 post to this group, send email to [email protected] >>>>> <mailto:[email protected]>. >>>>> Visit this group at https://groups.google.com/group/everything-list >>>>> <https://groups.google.com/group/everything-list>. >>>>> For more options, visit https://groups.google.com/d/optout >>>>> <https://groups.google.com/d/optout>. >>>> >>> >>> >>>> >>>> >>>> >>>> -- >>>> 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 post to this group, send email to [email protected] >>>> <mailto:[email protected]>. >>>> Visit this group at https://groups.google.com/group/everything-list >>>> <https://groups.google.com/group/everything-list>. >>>> For more options, visit https://groups.google.com/d/optout >>>> <https://groups.google.com/d/optout>. >>> >>> >>> >>> -- >>> 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 post to this group, send email to [email protected] >>> <mailto:[email protected]>. >>> Visit this group at https://groups.google.com/group/everything-list >>> <https://groups.google.com/group/everything-list>. >>> For more options, visit https://groups.google.com/d/optout >>> <https://groups.google.com/d/optout>. >> > > >> >> >> >> -- >> 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 post to this group, send email to [email protected] >> <mailto:[email protected]>. >> Visit this group at https://groups.google.com/group/everything-list >> <https://groups.google.com/group/everything-list>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > > > > -- > 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 post to this group, send email to [email protected] > <mailto:[email protected]>. > Visit this group at https://groups.google.com/group/everything-list > <https://groups.google.com/group/everything-list>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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