On Fri, Aug 2, 2019 at 5:18 PM 'Brent Meeker' via Everything List < [email protected]> wrote:
> > > On 8/2/2019 1:41 PM, Jason Resch wrote: > > > > On Fri, Aug 2, 2019 at 3:31 PM 'Brent Meeker' via Everything List < > [email protected]> wrote: > >> >> >> On 8/2/2019 1:19 PM, Jason Resch wrote: >> >> >> >> On Fri, Aug 2, 2019 at 3:17 PM 'Brent Meeker' via Everything List < >> [email protected]> wrote: >> >>> >>> >>> On 8/2/2019 12:53 PM, Jason Resch wrote: >>> >>> >>> >>> On Fri, Aug 2, 2019 at 1:25 PM 'Brent Meeker' via Everything List < >>> [email protected]> wrote: >>> >>>> >>>> >>>> On 8/2/2019 10:42 AM, Jason Resch wrote: >>>> >>>> Quantum computers work by interference of quits, and such interference >>>>>>> can only take place in one world -- different worlds are orthogonal. The >>>>>>> fact that one can analyse a quantum computer in a particular basis which >>>>>>> can be represented as a series of parallel computations does not mean >>>>>>> that >>>>>>> this is actually what happens. Heuristic constructs seldom correspond to >>>>>>> reality. >>>>>>> >>>>>> >>>>>> None of this comes anywhere close to addressing my question. >>>>>> >>>>> >>>>> Well, you have either not understood the question, or my answer to it. >>>>> >>>> >>>> I asked where those 10^1000 intermediate computation states are >>>> realized, and your reply was a basic description of how quantum computers >>>> use qubits and interference. You said this all takes place in one world, >>>> but the total information content and computational capacity of the >>>> observable universe about 800 orders of magnitude less than 10^1000. >>>> >>>> You then added a sentence that suggested the intermediate computational >>>> states perhaps don't exist, but then how does the correct answer get into >>>> the output bits when we read it? >>>> >>>> David Deutsch said he has never seen a sensible answer to the question >>>> of how quantum computers work from the context of any single-universe >>>> interpretation. Do you think your answer would satisfy him? >>>> >>>> >>>> All those "intermediate computation states" are so "numerous" because >>>> the state is being expressed as a superposition of qubit basis states. >>>> From another viewpoint the state is just a single ray in Hilbert space that >>>> happens to not be orthogonal to any of those bases >>>> >>> >>> So in your view, are they real? >>> >>> >>> What "they"? There's only a single state. It's like saying there are >>> infinitely many tones in a square wave...just because you represented it as >>> a Fourier series. The are 2^1e4 potential measurement results, depending >>> on what you choose to measure...but that's true in the classical case too. >>> >> >> Do you agree the final states you measured were caused by the >> intermediate states of the computation? >> >> How many intermediate states of the computation are there? >> >> >> One. It's a unitary evolution of the input state. >> > > We were speaking of computational states. Are you saying there is only > one computation state involved in Shor's algorithm? What causes the > interference necessary to yield the correct answer, if not these numerous > computational states? > > > The interference is in the measurement which Deutsch would say projects > out onto one of the multiple worlds...the non-unitary step. > > Does anyone claim interference happens during the measurement? In the double slit experiment the interference happens when the two photons overlap in their position, not when they strike the photographic plate. Deutsch says as much in his introduction to Fabric of Reality when speaking of shadow selves and shadow photons. In any case, you have still managed to avoid the question of the reality of the 10^1000 intermediate computational states. I won't press for an answer if you don't have one. Jason -- 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/CA%2BBCJUgY6MOpNrKgum_r4ai-6HBMhUwLiTeOSB36xc6eFdRS%3DQ%40mail.gmail.com.
