On Thursday, October 17, 2019 at 6:05:00 PM UTC-5, Brent wrote: > > > > On 10/17/2019 2:35 PM, Bruce Kellett wrote: > > I think you have misunderstood the experiments. The interference pattern > is present if the welcher weg information is erased, whether the erasure > takes place before or after the photons hit the screen. If the information > is not erased, no interference pattern is seen, even if the idler photons > drift off to infinity. > > * > Deutsch was simply wrong when he thought that his experiment would >>> "prove" the existence of many worlds.* >>> >> >> Actually Deutsch didn't say that, he said his experiment would test Many >> Worlds not prove it correct. >> > > OK. But the alternative that Deutsch seems to have been testing was that > only a conscious observer could collapse the wave function. As I have said, > this has never been a serious scientific position. > > When the exparament is actually performed for all I or Deutsch knows it >> could prove that the Many Worlds idea is dead wrong. I've already told you >> what my best guess on the outcome so what is your prediction? When that >> photographic plate is developed will there be interference bands on it or >> not? >> > > If the welcher weg information is quantum erased, then there will be an > interference pattern, whether or not it is a conscious observer who is > erased. > > > In Carroll's version of the experiment, which has been performed > arXiv:quant-ph/9903047 v1 13 Mar 1999, the experimenter who arranged that > each electron has its welcher weg recorded by a spin UP (left slit) or spin > DOWN (right slit) particle does, at the end of the experiment, knows > there's a record of which slit each electron went thru, and he can sign an > affadavit that says that information is known. But he doesn't know it > *consciously*; it's recorded by all the spin particles, but not in his > memory that he can bring to consciousness. We know what happens if he > signs such an affadavit or if he doesn't, it's the same: if the recording > spin particles are measured in a left/right basis the information is erased > and the interference pattern can be discerned by considering only particles > that measured left or only those measuring right. > > So Deutsch was proposing to test whether the* conscious *AI which could > have the recording particles as part of it's memory and presumably be > conscious of the up/down spins before they were erased would produce a > different result. > > But I wonder what happens in Carroll's experiment if, after measuring in > the left/right basis and noting that two different interference patterns > can then be discerned by considering either those due to left spin > recording particles or considering right spin particles, one measures the > recording particles again in the up/down basis. The overall pattern is the > same, it's just that you've relabeled spots on the screen according to > whether the second measurement of recording particles assigned them to UP > or to DOWN. Now you can consider the subset labeled UP (or DOWN). This > should be a superposition of ensembles randomly selected from the left and > right ensembles and in that case would not show an interference > pattern...but the information has certainly been erased (twice)? > > Brent >
So, in the end, it seems that reading Carroll's book is a huge waste of time after all, if his "explanation" leads to confusion. @philipthrift -- 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/95db0507-085c-48dc-9a62-d94a4ab5f55b%40googlegroups.com.
