On Wednesday, August 7, 2019 at 4:23:46 AM UTC-5, Bruno Marchal wrote: > > > On 6 Aug 2019, at 20:00, 'Brent Meeker' via Everything List < > [email protected] <javascript:>> wrote: > > > > On 8/6/2019 6:38 AM, Bruno Marchal wrote: > > If the QC does its task effectively, the output basis qbits will be put > into definite states, > > > Relatively to the observer, but in the global state, the observer will > inherit the superposition state, by linearity of the tensor products and of > the evolution. > > > In something like Shor's algorithm there is only one final state with > non-vanishing probability. Yet this is the kind of algorithm that Deutsch > cites as proving there must be many worlds. > > > Can you wrote a classical emulator of the algorithm of Shor which does not > emulate the “parallel computation”? > > I have never succeeded. I agree that this proves nothing, but QM without > the superposition (the parallel histories) does not (yet) make any sense to > me. That there is only one final state does not explain how shor’s > algorithm works without the intermediate superposed states. > > It is the same with Deutsch Josza problem, and some others. In fact, as > Deutsch said and explain well, even the two slits experiment is hard to > explain without attributing a physical existence to the superposed state. > The difference of the behaviour between pure sate and mixture seems to > impose some notion of parallel histories. > > Bruno > > > Exactly. That's the whole thing about quantum computing. It uses the quantum "substrate" to get parallelism.
https://groups.google.com/forum/#!topic/everything-list/WkTojsO0LhY @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/5761cb33-1339-42dc-b94d-8e2c91fb565c%40googlegroups.com.
