On Wednesday, May 23, 2018 at 3:29:21 AM UTC, [email protected] wrote: > > > > On Wednesday, May 23, 2018 at 2:24:07 AM UTC, Bruce wrote: >> >> From: <[email protected]> >> >> >> On Wednesday, May 23, 2018 at 1:45:39 AM UTC, Brent wrote: >>> >>> >>> >>> On 5/22/2018 5:59 PM, [email protected] wrote: >>> >>> >>> >>> On Wednesday, May 23, 2018 at 12:44:06 AM UTC, Brent wrote: >>>> >>>> >>>> >>>> On 5/22/2018 3:46 PM, [email protected] wrote: >>>> >>>> >>>> >>>> On Tuesday, May 22, 2018 at 10:41:11 PM UTC, [email protected] >>>> wrote: >>>>> >>>>> >>>>> >>>> I did, but you're avoiding the key point; if the theory is on the right >>>> track, and I think it is, quantum measurements are irreversible FAPP. The >>>> superposition is converted into mixed states, no interference, and no need >>>> for the MWI. >>>> >>>> >>>> You're still not paying attention to the problem. First, the >>>> superposition is never converted into mixed states. It *approximates*, >>>> FAPP, a mixed state* in some pointer* basis (and not in others). >>>> Second, even when you trace over the environmental terms to make the cross >>>> terms practically zero (a mathematical, not physical, process) you are >>>> left >>>> with different outcomes with different probabilities. CI then just says >>>> one of them happens. But when did it happen?...when you did the trace >>>> operation on the density matrix? >>>> >>> >>> I think the main takeaway from decoherence is that information isn't >>> lost to other worlds, but to the environment in THIS world. >>> >>> >>> But that ignores part of the story. The information that is lost to the >>> environment is different depending on what the result is. So if by some >>> magic you could reverse your world after seeing the result you couldn't get >>> back to the initial state because you could not also reverse the "other >>> worlds". >>> >> >> What "other worlds"? If they don't exist, why should I be concerned about >> them? AG >> >> >> I think you are ignoring the facts of the mathematics of unitary >> evolution of the wave function. Under unitary evolution the wave function >> branches, one branch or each element of the superposition, which is, one >> branch for each possible experimental result. These branches are in the >> mathematics. Now you can take all branches as really existing every much as >> the observed result exists -- that is the MWI position. Or you can throw >> them away as not representing your experimental result -- which is the >> collapse position. But in both cases, the evolution of the wave function >> shows that there is information in each mathematical branch. If you discard >> the branches (collapse) you throw this information away: if you retain the >> branches as other worlds, the information becomes inaccessible by >> decoherence and partial tracing. >> >> The situation is the same in either approach. Brent and I are not being >> inconsistent, devious, or otherwise tricky by referring to both MWI and CI >> approaches -- we are just recognizing the actual mathematics of quantum >> mechanics. The mathematics has to be interpreted, and different >> interpretations are available for the way in which the information in other >> branches is treated. >> >> Bruce >> > > Consider this interpretation of the wf, which for simplicity I consider as > a superposition of two eigenfunctions, and based on the probability > amplitudes represents a 50% probability of each outcome at some point in > time. Since the measurement hasn't occurred, where does this information > reside? Presumably it all resides in THIS world. As time evolves the > probability distribution changes, say to 75-25, and later to 90-10, and so > on. All of this information resides in this world since without a > measurement occurring, there are no other worlds, and no collapse. Suppose > at some point in time, the values changed to 100-0, Isn't 100-0 as good as > other pair if they sum to zero? And why would anyone think another world > comes into existence because one of the values evolved to 0? I will now > define, in answer to one of Brent's questions, when the measurement occurs. > I assert it occurs when one of the pair of values equals 0, All throughout > all information was in this world. Why would another world come into > existence if one of the values happened to be 0? AG >
I meant to write above "Isn't 100-0 as good as any other pair if they sum to 100?" 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]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
