On Thursday, November 30, 2017 at 11:16:07 PM UTC, agrays...@gmail.com wrote: > > > > On Thursday, November 30, 2017 at 9:47:37 PM UTC, Bruce wrote: >> >> On 30/11/2017 10:59 pm, agrays...@gmail.com wrote: >> >> On Thursday, November 30, 2017 at 11:42:51 AM UTC, Bruce wrote: >>> >>> On 30/11/2017 10:32 pm, agrays...@gmail.com wrote: >>> >>> On Thursday, November 30, 2017 at 4:08:20 AM UTC-7, Bruce wrote: >>>> >>>> On 30/11/2017 9:53 pm, agrays...@gmail.com wrote: >>>> >>>> On Wednesday, November 29, 2017 at 10:40:36 PM UTC, Bruce wrote: >>>> >>>> On 30/11/2017 5:31 am, John Clark wrote: >>>> >>>> On Tue, Nov 28, 2017 at 10:59 PM, Bruce Kellett < >>>> bhke...@optusnet.com.au> wrote: >>>> >>>> >>>> > >>>> I see no reason all the Everett worlds have the same physics, >>>> >>>> >>>> > >>>> Everettian worlds follow from assuming that the Schrödinger equation >>>> applies everywhere without exception, so that all physical evolution is >>>> unitary. A change in the underlying physics -- such as a change in the >>>> value of fundamental constants, Planck's constant or Newton's constant for >>>> example -- would not be unitary, so cannot occur in MWI. >>>> >>>> >>>> >>>> Why can't it be unitary?? Show me why if >>>> >>>> Newton's constant had any value other than >>>> >>>> 6.754* 10^-11 m3 kg^−1 s^−2 >>>> >>>> the sum of all quantum probabilities would no longer add up to exactly >>>> 1. If you can really do that then you've just derived Newton's constant >>>> directly from first principles and you should but a ticket to Stockholm >>>> right now because you're absolutely certain to win the next nobel Prize. >>>> >>>> Although unitarity does mean that probabilities always sum to unity, >>>>> that is a consequence of unitary evolution, not a definition of it. A >>>>> unitary transformation is one that can be reversed: so the unitary >>>>> operator >>>>> U can be written as exp(-iH), for example, and the complex conjugate (or >>>>> the adjoint for hermitian operators) is the inverse transformation. >>>>> >>>> *Considering the evolution of the wf, if there exists a DE that >>>>> describes the collapse process, would it necessarily be nonlinear? Is >>>>> nonlinear a problem; that is, what is the downside to nonlinear? How >>>>> would >>>>> it effect the issue of hidden variables? TIA, AG * >>>>> >>>> >>> Collapse would be non-linear and non-unitary -- >>> intrinsically non-reversible. This is not necessarily a problem since there >>> are plenty of non-linearities in physics. It has nothing to do with hidden >>> variables. >>> >>> *Why would it be non linear? Brent claimed (on page 1)* >>> >>> >>> Page 1 of what? >>> >> >> >> *On Google it's organized as pages, now up to page 15. Go to top of >> thread and read second message by Brent. AG * >> >>> >>> * that if the QM could be made deterministic, say by a DE that described >>> collapse, it would imply awful consequences, such as the future determining >>> the past.* >>> >>> >>> No, it wouldn't imply that. >>> >>> * Would making QM into a deterministic theory imply an inconsistency in >>> the postulates of QM? TIA, AG* >>> >>> >>> QM in MWI is deterministic. Bohm's theory is deterministic, though >>> expressly non-local. Determinism is not really an issue. One world theories >>> are intrinsically random, not deterministic. >>> >> >> *How can MWI be deterministic if it can't tell us what outcome we will >> observe in this world, or any other? AG* >> >> >> Because MWI says that all outcomes are realized, each in a separate >> world. Apparent randomness comes about because we don't know which world we >> will end up in (though we actually end up in all the worlds, so we, or our >> duplicates, observe all possible outcomes). >> >> Bruce >> >
*OK. I wouldn't use "deterministic" to describe that situation, but that's neither here nor there. More important is Brent's reply to my question which started this discussion thread. He stated that a deterministic ONE WORLD version of QM would have dire effects, such as the future influencing the past. His exact words are in the 2nd message in this discussion. You don't seem to share this view. I know that Bohm developed a deterministic version of QM which is expressly non-local and not covariant. I don't think it's what Brent was referring to. Also, I noticed that Bruno, our resident enthusiast of arithmetic as the solution to all enigmas, stated that Weinberg showed that a non-linear SWE to explain collapse would imply that the laws of thermodynamics are flawed. Is this your understanding? TIA, 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 everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
