On Wed, Aug 7, 2019 at 10:04 AM smitra <[email protected]> wrote: > On 07-08-2019 00:45, Bruce Kellett wrote: > > > The trouble with that argument is that in any simulation, you get to > > set the rules of physics that obtain. There is then no guarantee that > > the results of your simulation have any relation to physics in the > > real (unassimilated) world. For decoherence to work, all that is > > required is a sufficient number of environmental degrees of freedom > > for multiple copies of the result to be recorded by the "environment > > as witness", in Zurek's words. Quantum Darwinism then ensures that the > > result is permanent and irreversible. > > If you measure the z-component of a spin polarized in the x-direction, > then however astronomically large the number of environmental degrees of > freedom there are that get entangled with the spin, it's still a finite > number. One minute after the measurement all the degrees of freedom that > can be entangled are within one light-minute of the experimental set-up. > So, the recording of the result in the environment are going to be a > superposition of the two possible recordings. >
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. 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/CAFxXSLR8CTLwit7B-y2WTzBdA0Pph2wpa4ZnTUhTCxNtab5vOQ%40mail.gmail.com.
