On Wed, Aug 7, 2019 at 1:54 PM smitra <[email protected]> wrote: > On 07-08-2019 02:19, Bruce Kellett wrote: > > > > It is called the "relative state" interpretation for a reason. The > > entanglement with the environmental degrees of freedom that leads to > > the recording of the result in the environment is relative to each > > possible experimental outcome. Within the decoherence time (typically > > of the order of a few nanoseconds or less) these "relative states" > > become effectively orthogonal, and the measurement becomes > > irreversible. Because there is no longer any possibility of > > interference between the results, there is no longer any > > superposition. You guys seems so desperate to hold on to a > > superposition that no longer has any practical consequences. Get used > > to it -- measurements have definite outcomes. That is the fact that > > has to be incorporated into your theory. > > Yes, but this is relative to each component. The inability to > demonstrate interference does not demonstrate that there is no > superposition.
If the superposition has no observable effect, can it be said to still exist? > To prove that these superpositions really can vanish you > need to do an experiment that demonstrates a violation of unitary time > evolution of a completely isolated system. There is no such thing as a measurement on a completely isolated system. > Saying that there is no > superposition just because in a particular experiment you cannot see a > particular signature of that anymore, is like saying that momentum isn't > conserved if we bounce a ball against the ground. The inability to > detect the change in the momentum of the Earth doesn't mean that there > is no such change. Unitary time evolution is established just as > rigorously as momentum conservation. > Unitary evolution is an assumption. It is manifestly violated in essentially every experiment that is performed. As I said, it serves no useful purpose to maintain that the superposition persists after a definite result has been obtained. It might satisfy your existential angst, but it has no role in physics. Bruce -- 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/CAFxXSLTbediOozjPGS6OcO-DJgYqt1VzSrgq20BR9dqHPF1G8w%40mail.gmail.com.
