On 4/17/2016 4:34 PM, Bruce Kellett wrote:
On 18/04/2016 5:25 am, Jesse Mazer wrote:
"A and B perform their measurements at spacelike separation, but each
chooses the measurement orientation outside the light cone of the
other. There are four possible combinations of results, corresponding
to four worlds in the MWI: |+>|+'>, |+>|-'>, |->|+'>, and |->|-'>.
Since each observer has a 50% chance of getting |+> and 50% of
getting |->, and the two measurements are completely independent of
each other, it would seem that each of these four worlds is equally
likely."
I don't think this is how it's supposed to work for those who argue
the MWI is local like Deutsch. Rather the idea is that "splitting"
into worlds is local, not global; so one experimenter locally splits
into copies that see |+> and |-> when they measure their particle,
likewise the other experimenter splits into copies that saw |+'> and
|-'>. But until their future light cones overlap there are no
"worlds" containing facts about what *both* experimenters saw. And
once they do overlap--say, because they both sent signals about their
results to an experimenter at the midpoint between them
The future light cones of the observers will overlap at a time
determined by their initial separation, regardless of whether they
send signals to each other or not.
Right. No explicit communication of results in required. It is
presumably decoherence that ensures that whenever Alice and Bob do
communicate they are not in a |+>|+> or |->|-> world. The interesting
question is whether we are assuming that in the region that is spacelike
relative to both Alice and Bob's measurement (where no information about
the results can possibly have been propagated) the wf has "collapsed".
If you take an epistemic view of the wf, this is a meaningless
question. In an ontic view of the wf it is usually assumed that it has
collapsed violating FTL but in an undetectable way.
Brent
--
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 post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
