On Tue, May 7, 2019 at 5:44 PM 'Brent Meeker' via Everything List < everything-list@googlegroups.com> wrote:
> > > On 5/7/2019 2:52 PM, Jason Resch wrote: > > > > On Tuesday, May 7, 2019, 'Brent Meeker' via Everything List < > everything-list@googlegroups.com> wrote: > >> >> >> On 5/7/2019 2:08 PM, Jason Resch wrote: >> >> >> >> On Tuesday, May 7, 2019, 'Brent Meeker' via Everything List < >> everything-list@googlegroups.com> wrote: >> >>> >>> >>> On 5/7/2019 1:49 PM, Jason Resch wrote: >>> >>> >>> >>> On Tuesday, May 7, 2019, 'Brent Meeker' via Everything List < >>> everything-list@googlegroups.com> wrote: >>> >>>> >>>> >>>> On 5/7/2019 11:52 AM, Jason Resch wrote: >>>> >>>> >>>> >>>> On Tue, May 7, 2019 at 1:07 PM 'Brent Meeker' via Everything List < >>>> everything-list@googlegroups.com> wrote: >>>> >>>>> >>>>> >>>>> On 5/7/2019 9:53 AM, Jason Resch wrote: >>>>> >>>>> >>>>> >>>>> On Tuesday, May 7, 2019, 'Brent Meeker' via Everything List < >>>>> everything-list@googlegroups.com> wrote: >>>>> >>>>>> >>>>>> >>>>>> On 5/6/2019 11:11 PM, Jason Resch wrote: >>>>>> >>>>>> Not at all. In fact a quantum computation only works because all the >>>>>>> wrong answers have a high probability of being eliminated by destructive >>>>>>> interference...which requires that they be computed in the same world. >>>>>>> >>>>>> >>>>>> So prior to the computation, all of the wrong answers existed? >>>>>> >>>>>> >>>>>> There is no answer until the output is measured. >>>>>> >>>>>> >>>>>> Brent >>>>>> >>>>> >>>>> >>>>> Then what did you mean by "all the wrong answers have a high >>>>> probability of being eliminated". Eliminated from what? >>>>> >>>>> >>>>> I mean not showing up as the answer. >>>>> >>>> >>>> And they don't show up because... ? >>>> >>>> >>>> Their amplitude in the superposition is small. If you've got something >>>> to say, just say it. >>>> >>>> >>>> Brent >>>> >>> >>> >>> You seem to be avoiding the implication that the system starts in a >>> state where all possible answers, both wrong and correct exist. >>> >>> >>> You seem to think that because something might exist in the future it >>> exists. >>> >>> >>> Brent >>> >> >> >> >> At what point in time does "the probability of measuring the wrong >> answers" decrease? >> >> 1. Before the computation >> 2. During/after the computation >> 3. At the time of measurement >> 4. Something else >> 5. Indeterminate >> >> My guess is #2, what do you think? >> >> During/after is pretty broad. You're assuming that when the answer is >> measured can be varied independently of the computation. Even classical >> computations don't have an answer ready to be output at any time. Some do, >> but interate so that the answer becomes more accurate with run time. So I >> think it depends on the structure of the algorithm. >> >> >> Brent >> > > > Is there an algorithm where the answer would be something other than > during or after? > > > Since the question was ''At what *point* in time does "the probability of > measuring the wrong answers" decrease?'' I don't thing "during/after" is > even an answer. > > As I said, I think no answer exists until there's a measurement, the > computer will be in a superposition of states relative to the measurement > basis. So "at the time of measurement" would be the closest answer. But I > know some algorithms, like Grover's, become more accurate as they run > longer. > Isn't there an easy experiment to test your theory? Run the following experiment: Execute the same quantum computation simultaneously on 5 different quantum computers. Then: 1. On computer #1, perform the measurement 1 year after the computation completes 2. On computer #2, perform the measurement 2 hours after the computation completes 3. On computer #3, perform the measurement 1 hour after the computation completes 4. On computer #4, perform the measurement as soon as the computation completes 5. On computer #5, perform the measurement before the computation completes Given that QM would give us the same probability of obtaining the correct answer from computers 1 through 4, and a different (lower) probability of obtaining the correct answer from computer #5, and given that the measurements take place at different times (with the earliest taking place as soon as the computation completes), doesn't this suggest to you that the probabilities are determined prior to the time of the measurement? 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 everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CA%2BBCJUgHfyVV%2BCNUd1mhZUomy9aunbBRDvDJPko5pJjvbzR9ow%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
