> On 7 Aug 2019, at 00:37, Bruce Kellett <[email protected]> wrote: > > On Wed, Aug 7, 2019 at 4:00 AM 'Brent Meeker' via Everything List > <[email protected] <mailto:[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. > > Exactly. So there are no other components in superposition. Bruno wants to > characterize this as a collapse. But without this happening, the QC would be > unreliable -- there would be some finite probability that you would get the > wrong result. As I understand it, there are some QC algorithms that do not > lead to definite results, so you have to run them several times to reduce the > probability of a wrong answer to some acceptable level. > > As usual, Bruno is introducing irrelevancies in order to distract attention > from the fact that he cannot answer the central contention of my argument -- > which is that quantum computer do not provide any evidence for the existence > of parallel worlds. They can work perfectly well in just one world -- without > any collapse whatsoever.
I can’t explain even just the two slits without superposition. “Parallel worlds/histories” are just a popular name to describe a superposition. Then nothing in the QM linear evolution can explain how the superposition disappear, although the decoherence theory explain why it is hard to see a macro-superposition. Shor algorithm does not make them disappear, even if it manages to get the result with high probability in the branch we are situated in. Bruno > > Bruce > > Yet this is the kind of algorithm that Deutsch cites as proving there must > be many worlds. Brent > > > > -- > 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLTNyfc01ESYvTCEnqJo8ZU0Paa6Ce9MExoQ-UoMs3YUKQ%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLTNyfc01ESYvTCEnqJo8ZU0Paa6Ce9MExoQ-UoMs3YUKQ%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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/DB51C449-6073-43A4-9D1A-D540B5FA9AD7%40ulb.ac.be.
