On Friday, October 18, 2019 at 9:39:41 AM UTC-5, John Clark wrote: > > On Thu, Oct 17, 2019 at 5:35 PM Bruce Kellett <[email protected] > <javascript:>> wrote: > > *> I see, Deutsch was testing the idea that it was consciousness that >> collapsed the wave function. But, apart from a few flirtations with the >> idea, none has ever taken that seriously. It is certainly not part of the >> Copenhagen Interpretation.* [...] *given SR, there can be no signal >> informing one observer of the other's results.* >> > > I see.... no I take that back I don't see. You used a very odd word in > the above that I don't understand at all, the word is "observer". > > >> *> if you erase or not the welcher weg information 'before' the signal >> photon hits the screen, then presumably some, presently unknown physics, >> could send this information to the screen and influence the result there.* >> > > So you admit it. If you continue to insist Many Worlds do not exist then > to explain an experiment that has been performed many times you must > postulate new physics and mess with Schrodinger's Equation. > > >> *> The reason for erasing or not *after* the signal photons hit the >> screen is to eliminate this possibility -- any signal to the screen would >> have to be backwards in time.* >> > > If you decide to erase or not to erase after the photon passes the slits > but before it hits the photographic plate then to explain the results > you've either got to embrace Superdeterminism, backward causality or Many > Worlds. If you erase the information after the photon hits the photographic > plate then you don't have to embrace anything because the experiment would > tell you nothing. It's called The Wheeler Delayed Choice Experiment but > it was actually first proposed in 1926 by Gilbert Lewis (he also coined the > word "photon"), but it remained just a thought exparament for 81 years and > was not actually performed until 2007. > > Experimental realization of Wheeler’s delayed-choice GedankenExperiment > <https://arxiv.org/pdf/quant-ph/0610241v1.pdf> > > Why do you suppose that is, why the big delay between thought experiment > and real experiment? Because although it's simple in concept it's very > difficult to actually perform, you need super fast electronics and a very > good random number generator to make the split second decision to erase or > not to erase in the ultra short amount time between the photon passing the > slit and it hitting the photographic plate. If you could take your time and > wait until after it hit the plate Lewis could have not just talked about it > but actually done the exparament in 1926 and he wouldn't have needed > advanced electronics; steam powered, or even horse powered, machinery > would have been good enough. > > >> >> After? Took the trouble? After would be easy, and pointless. It is >>> much more difficult to erase the which way information *after* the >>> photons hit the slits but *before* they hit the screen, it would also >>> be far more informative. >>> >> >> The interference pattern is present if the welcher weg information is > erased, > > Yes, > > >> *> whether the erasure takes place before or after the photons hit the >> screen.* >> > > Yes but you can't expect to learn anything if you look at the developed > photograph and then decide whether to erase the which way information or > not. If you decide to erase the information do you imagine you will see the > photograph change before your eyes?? > > > *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.* >> > > If that's the way the exparament turns out and a interference pattern > exists but Many Worlds does not exist then how do you explain the existence > of a signed document testifying that somebody observed the photon going > through one and only one slit and the he knew which one? Inquiring minds > want to know. > > John K Clark >
That appears right and that Sabine Hossenfelder would agree. So if there just just One World, what does that tell you? @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/85a123ab-35a2-4ad4-9ffb-7b4d132bc4df%40googlegroups.com.
