On 15/11/2017 1:18 am, Bruno Marchal wrote:
On 13 Nov 2017, at 22:40, Bruce Kellett wrote:
On 14/11/2017 2:07 am, Bruno Marchal wrote:
On 12 Nov 2017, at 23:05, Bruce Kellett wrote:
What really annoys me is the continued claim that many worlds
eliminates the need for non-locality. It does not, and neither
Bruno nor anyone else has ever produced a valid argument as to how
many worlds might restore locality.
But nobody has proved that there is non locality in the MWI.
EPR-BELL proves non-locality apparant in each branch, but the MWI
avoids the needs of action at a distance to explains them. Once
Alice and Bob are space-separated, their identity are independent.
It makes no sense to talk of each of them like if they were related,
(unless you correlate them with a third observer, etc) If they do
measurement, some God could see that they are indeed no more
related, but if they decide to come back to place where they can
compared locally their spin, they will always get contact to the
corresponding observer with the well correlated spin. The
independent Alice and Bob will never meet because they can't belong
to the same branch of the multiverse, by the MWI of the singlet
state. So Mitra is right. Although Bertlmann's socks are tyically
not working for Bell's violation in a MONO-universe, it works again
in the MWI, applied in this case to the whole singlet state.
Bell has proved non-locality in MWI, every bit as much as in each
branch separately. You appear not to have grasped the significance of
the scenario I have argued carefully. Alice and Bob are not
space-like separated in the scenario I outlined. Alice and Bob are
together in the same laboratory when the second measurement is made.
They are necessarily in the same world before, and branch in together
according to Bob's result. Your mumbo-jumbo about them only being
able to meet in appropriate matching branches does not work here,
because they are always in the same branch. And there is no reason to
suppose that their results in some of those branches do not violate
conservation of angular momentum.
I have no clue what you mean. The singlet state guaranties the
conservation of angular momentum in all worlds. The singlet state
describes an infinity of "worlds", and in each of them there is
conservation of angular momentum, and it has a local common cause
origin, the same in all worlds.
Tell me what you don't understand and I will attempt to explain it more
clearly, as I did when Brent asked about the confusion of negatives in
my final sentence above. (I meant that, given locality, there are
branches in the above scenario that violate angular momentum conservation.)
Local common cause explanations (aka 'Bertlmann's socks') have been
known not to give the correct quantum correlations since at least Bell's
time.
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 everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.