On Wednesday, August 7, 2019 at 10:30:44 AM UTC-5, Jason wrote: > > > > On Tue, Aug 6, 2019 at 5:29 PM 'Brent Meeker' via Everything List < > [email protected] <javascript:>> wrote: > >> >> >> On 8/6/2019 11:25 AM, Philip Thrift wrote: >> >> >> >> On Tuesday, August 6, 2019 at 1:00:23 PM UTC-5, Brent 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. >>> >>> Brent >>> >> >> >> >> That there is a multiplicity of *somethings* >> >> https://en.wikipedia.org/wiki/Multiple_histories >> >> is the basis for all semantics of quantum computing (by computer >> scientists) that I have ever seen. >> >> >> Same for classical computation...there are lots of states or functions. >> Did anyone think there had to be multiple worlds for the computer to work? >> > > I think all of our disagreement comes down to the definition of world. > > If you define the world as the state of in some Hilbert space, you only > need one such "WORLD". If you define world as a collection of interacting > objects, that is itself causally isolated from other such "worlds" (for all > practical purposes), then you get many of those, within the Hilbert space. > > This is made most clear in the case of a quantum computer. Where the > quantum computer can be viewed as one WORLD (def 1) that contains many > little worlds (def 2), where each computational trace constitutes its own > little world, causally isolated from the rest. We would have no evidence > those other traces even existed, except for the special cases we can > arrange in the quantum computer to cause those many worlds to interfere > with each other. (As is what's done in Shor's algorithm) > > Jason >
>From Sean Carroll's blog: Guest Post: Chip Sebens on the Many-*Interacting*-Worlds Approach to Quantum Mechanics http://www.preposterousuniverse.com/blog/2014/12/16/guest-post-chip-sebens-on-the-many-interacting-worlds-approach-to-quantum-mechanics/ There is a world of "worlds" out there, and everyone has their own (idea of "world"). @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/ff8144a4-1496-42da-a4a0-753b612dec2e%40googlegroups.com.
