On Fri, Aug 2, 2019 at 6:51 PM 'Brent Meeker' via Everything List < [email protected]> wrote:
> > > On 8/2/2019 4:36 PM, Jason Resch wrote: > > > > 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. > > > You write as though they were classical particles. The wave function > reaches the photographic plate and then there is an interaction which is > greater or lesser depending on the interference pattern over the plate. > > To say interference happens at the time of measurement may be satisfactory for making predictions, but it is completely unsatisfactory for explanations. It is a way of stuffing the intermediate computations under the rug and pretending they were never there. What of the conscious states implied by the computations of an AI on a quantum computer? "Forget about them, they never really existed." > Deutsch says as much in his introduction to Fabric of Reality when > speaking of shadow selves and shadow photons. > > > You can stop quoting Deutsch. I think he's just a MWI envangelist. > Okay. It was only in response your mention of Deutsch. I thought you were suggesting Deutsch believed interference happens during measurement. > > > 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. > > > I already gave the answer. There is only one intermediate state. It just > happens to have lots of components in the basis you used to express it. > And each of those components represents a trace of a computation performed on one of the many possible values of the input qubits, do they not? 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%2BBCJUjHJpfEkvAH7eNEUY72kpvACbrPPuHgn_jncgpmjZZtJw%40mail.gmail.com.
