On Friday, August 2, 2019, 'Brent Meeker' via Everything List < [email protected]> wrote:
> > > On 8/2/2019 4:59 PM, Jason Resch wrote: > > > > On Fri, Aug 2, 2019 at 6:44 PM Bruce Kellett <[email protected]> > wrote: > >> On Sat, Aug 3, 2019 at 9:36 AM Jason Resch <[email protected]> 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: >>>> >>>> [Brent]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. >>> >> >> Brent is correct. There is only ever one state -- one vector in Hilbert >> space. The computation involves nothing more than unitary rotations of this >> vector in Hilbert space. The final result is obtained by projecting this >> state on to some set of basis vectors. None of the intermediate projections >> on to arbitrary basis vectors is "real" in any sense, since such basis >> vectors are arbitrary. >> > > A lot of computational work gets done for by something that isn't real in > any sense. > > > The wave function is real (if you prefer the ontic interpretation)...but > there's only one state described by it. > > > >> >> So, in that sense, the final measurement does do the interference >> because it involves a choice of a particular basis. Just as the spots on >> the screen behind a double-slit experiment decide the interference -- they >> amount to a choice of basis in position space -- position along the axis of >> the screen. >> >> > So the Morpho butterfly isn't sending out blue light until you look at it? > > > It isn't sending out blue photons until they interact with the environment. > > > This would imply a rather strange form of retrocausality. It would imply that a cat with an hour's worth of accumulated experiences spontaneously appears the instant you open the box. Can we really not speak of the evolution of the wavefunction over time when no one is looking? 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%2BBCJUgKz7z4%3Dm9ePUTkhKfvFo-FS7TR6cYktS3d5GF5wbfW4A%40mail.gmail.com.
