On Sun, May 15, 2022 at 1:17 AM smitra <smi...@zonnet.nl> wrote: > On 13-05-2022 21:59, Brent Meeker wrote: > > > Right CI doesn't explain the collapse and MWI doesn't explain the > > collapse either but assumes it can be explained without new physics. > > I hypothesize (not assume) that CI+ <non-zero minimum probability> can > > explain the collapse. I don't see any big advantage for MWI here. > > The big advantage is that decoherence is a well researched area of > (mathematical) physics, results like the density matrix becoming > approximately diagonal, and relations between decoherence to entropy > increase making it effectively irreversible are all rigorous results > that are uncontroversial. People may still have objections against the > MWI, but they'll still accept these results on decoherence. >
Yes. And decoherence says that with time, the off-diagonal elements of the density matrix become arbitrarily small. If there is a smallest non-zero probability, then eventually these off-diagonal elements become zero. This reduces the pure state to a mixture. Which is to say that there is a collapse; unitary evolution ceases, and we have reached a classical world. Non-zero minimum probability on its own, however, does not cause a > system to evolve in a non-unitary way. It does when decoherence is taken into account. See the above explanation. Bruce has not omitted anything. Bruce Bruce is omitting something here, > perhaps some limits in which the time evolution operator becomes > degenerate or something like that. But a product of two unitary > transforms is a unitary transform, so the nth power of a unitary > transform is also a unitary transform. There is no ay you can get > anything non-unitary out of this, unless possibly in the limit of n to > infinity. > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLSqWc3OwbenyDa_-0rjvBYVFqFSQhubXUEu6-Lxsb1XNw%40mail.gmail.com.
