On Thursday, April 15, 2021 at 5:58:59 AM UTC-6 Bruno Marchal wrote:
> On 14 Apr 2021, at 16:33, Alan Grayson <[email protected]> wrote: > > > > On Wednesday, April 14, 2021 at 4:40:08 AM UTC-6 Bruno Marchal wrote: > >> On 10 Apr 2021, at 13:55, Alan Grayson <[email protected]> wrote: >> >> >> >> On Saturday, April 10, 2021 at 5:21:46 AM UTC-6 Bruno Marchal wrote: >> >>> On 9 Apr 2021, at 06:42, Alan Grayson <[email protected]> wrote: >>> >>> When the box is closed, and before the measurement, why can't it be >>> claimed that the Cat is in a Mixed State, not a Superposition of States? >>> Only the latter leads to the paradox of a cat which is Alive and Dead >>> simultaneously. AG >>> >>> >>> >>> Because the Wave equation in this setting leads to a pure state >>> dead+alive, and twe know that such pure state leads to different prediction >>> than any possible corresponding mixed states. (Assuming the SWE). >>> >> >> *Without any mathematical representation of the individual states of Dead >> and Alive, how can it be claimed that Dead and Alive each satisfy the SWE? * >> >> >> By NOT adding the collapse postulate. Then even a state as “macroscopic” >> as being a dead or alive cat will inherit the superposition ilmplied by >> Schroedinger’s setting. That follows from the double linearly of both the >> wave evolution and of the tensor products. The fact that a correct >> description would use a huge number of dimension and a lot of tensor >> products cannot be used to make the superposition going away. >> >> *And how will the superposition of states Dead + Alive give different >> predictions than a mixed state of Dead and Alive? AG * >> >> Because all pure superposition state gives different predictions than >> their corresponding mixed state. >> > > *Is this your idea of a proof, or even a plausibility argument? AG* > > It is elementary quantum mechanics. If you measure “1/sqrt(2)(spin-up + > spin-down)” is the base {spin-up, spin-down}, you get different results > than measuring a half-half mixture of spin-up and spin-dow. This is usually > illustrate with polarisers in the textbook. > > Bruno > *Can you give an example why the result will be different for superposition, say with 70%/30% probability amplitudes, versus a mixed state with same amplitudes. It may be simple to show, but I admit to not being able to see any difference between the cases. AG * -- 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/63e93e6e-e1ff-4369-b830-de6f051d4995n%40googlegroups.com.
