On Tuesday, October 15, 2019 at 4:14:39 PM UTC-5, John Clark wrote: > > On Tue, Oct 15, 2019 at 1:50 PM 'Brent Meeker' < > [email protected] <javascript:>> wrote: > >> > * > Curiously, Deutsch used a quantum computer in a thought experiment to >> prove multiple worlds.* > > > He did indeed, I read about it 30 years ago in Deutsch's book "The Ghost > In The Atom" and that was when I started to take the MWI seriously. > Deutsch's test would be very difficult to perform but the reason it's so > difficult is not the Many World's fault, the reason is that the > conventional view says conscious observers obey different laws of physics, > Many Worlds says they do not, so to test who's right we need a mind that > uses quantum properties. Quantum Computers have advanced enormously over > the last 30 years so I wouldn't be surprised if it or something very much > like it is actually performed in a decade or two. > > An intelligent quantum computer shoots photons at a metal plate one at a > time that has 2 small slits in it, and then the photons hit a photographic > plate. Nobody looks at the photographic plate till the very end of the > experiment. The quantum mind has detectors near each slit so it knows which > slit the various photons went through. After each photon passes the slits > but before they hit the photographic plate the quantum mind signs a > document saying that it has observed each and every photon and knows which > slit each photon went through. It is very important that the document does > NOT say which slit any photon went through, it only says that they went > through one slit and only one slit and the mind has knowledge of which > one. There is a signed document to this effect for every photon it shoots. > > Now the mind uses quantum erasure to completely destroy its memory of > which slit any of the photons went through; the only part remaining in the > universe is the document which states that each photon went through one and > only one slit and the mind (at the time) knew which one. Now develop the > photographic plate and look at it. If you see interference bands then the > Many World interpretation is correct. If you do not see interference bands > then there are no worlds but this one and the conventional quantum > interpretation is correct. > > This works because in the Copenhagen interpretation when the results of a > measurement enters the consciousness of an observer the wave function > collapses, in effect all the universes except one disappear without a trace > so you get no interference. In the Many Worlds model all the other worlds > will converge back into one universe because information on which slit the > various photons went through was the only thing that made one universe > different from another, so when that was erased they became identical again > and merged, but their influence will still be felt, you'll see ambiguous > evidence that the photon went through slot A only and ambiguous evidence it > went through slot B only, and that's what causes the interference pattern. > > John K Clark >
But the path integral is both interpretation of quantum computing - https://arxiv.org/abs/quant-ph/0607151 (2006) - and algorithm for the Google quantum computer simulator - https://arxiv.org/abs/1807.10749 (2018). The Google quantum computer paper does not mention "many worlds". @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/0376cafc-00ec-4446-9beb-a92cbe657188%40googlegroups.com.
