On Wed, Aug 7, 2019 at 6:23 AM Jason Resch <[email protected]> wrote:
> On Tue, Aug 6, 2019 at 1:00 PM 'Brent Meeker' via Everything List < > [email protected]> 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. >> > > If you trace the causality of the computation backwards, is that not the > implication? (Short of the final answer materializing out of no where for > no reason) > No, it is not the implication of tracing the causality of the computation backwards. The computation can be represented by unitary rotations of the state vector in Hilbert space. These rotations, since unitary, are certainly reversible. But at no stage do you encounter many worlds -- it all takes place in Hilbert space -- one world. The final result simply uses the resources of the 2^n-dimensional Hilbert space -- it does not require parallel worlds. Bruce -- 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/CAFxXSLR1af%3DaDQjyMaisNmYPiq_yLdxDmrrx7c87Um9J9%3D3XqA%40mail.gmail.com.
