On Sunday, October 20, 2019 at 6:35:10 PM UTC-6, Brent wrote: > > > > On 10/20/2019 4:58 PM, Alan Grayson wrote: > > On Sunday, October 20, 2019 at 11:35:13 AM UTC-6, Brent wrote: >> >> >> >> On 10/19/2019 6:56 PM, Alan Grayson wrote: >> >> Sean says the decoherence time is 10^(-20) sec. So when the box is >>> closed, the cat is in a superposition of alive and dead during that time >>> interval, assuming the decay hasn't happened. If that's the case, I don't >>> see how decoherence solves the paradox, unless we can assume an initial >>> condition where the probability of one component of the superposition, that >>> the cat is dead, is zero. Maybe this is the solution. What do you think? AG >>> >> >> Maybe this is an easier question; after decoherence, assuming the >> radioactive source hasn't decayed, what is the wf of the cat? Is the cat >> in a mixed state, alive or dead with some probabIlity for each? AG >> >> >> You can't "assume the radioactive source hasn't decayed". The point >> Schroedinger's thought experiment is that when the box is closed you don't >> know whether or not it has decayed and so it is in a superposition of >> decayed and not-decayed and the cat is correlated with these states, so it >> is also in a superposition of dead and alive. >> >> Brent >> > > I thought you might say this. OK, then what function does decoherence have > in possibly solving the apparent paradox of a cat alive and dead > simultaneously. TIA, AG > > > It doesn't necessarily solve "that problem". Rather it shows why you can > never detect such a state, assuming you buy Zurek's idea of envariance. > One way to look at it is it's the answer to Heisenberg's question: Where is > the cut between the quantum and the classical? Once envriance has acted, > then the result is classical, i.e. you can ignore the other possibilities > and renormalize the wave function. > > Brent >
Woudn't you agree that if the system, in the case a cat, goes classical after 10^(-20) sec, its state must be a mixture at that point in time even if the box hasn't been opened? 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/43aedf54-a007-42b3-aab5-c4ef02f72c3f%40googlegroups.com.
