On 12/31/2013 7:22 PM, LizR wrote:
On 1 January 2014 13:54, meekerdb <meeke...@verizon.net <mailto:meeke...@verizon.net>>
wrote:
On 12/31/2013 3:24 PM, LizR wrote:
On 1 January 2014 12:05, meekerdb <meeke...@verizon.net
<mailto:meeke...@verizon.net>> wrote:
Mark A. Rubin
<http://arxiv.org/find/quant-ph/1/au:+Rubin_M/0/1/0/all/0/1>
(Submitted on 14 Mar 2001 (v1
<http://arxiv.org/abs/quant-ph/0103079v1>), last
revised 10 May 2001 (this version, v2))
Bell's theorem depends crucially on counterfactual reasoning, and is
mistakenly interpreted as ruling out a local explanation for the
correlations which can be observed between the results of
measurements
performed on spatially-separated quantum systems. But in fact the
Everett
interpretation of quantum mechanics, in the Heisenberg picture,
provides an
alternative local explanation for such correlations.
Measurement-type
interactions lead, not to many worlds but, rather, to many local
copies of
experimental systems and the observers who measure their properties.
Transformations of the Heisenberg-picture operators corresponding
to the
properties of these systems and observers, induced by measurement
interactions, "label" each copy and provide the mechanism which,
e.g.,
ensures that each copy of one of the observers in an EPRB or GHZM
experiment will only interact with the "correct" copy of the other
observer(s). The conceptual problem of nonlocality is thus replaced
with a
conceptual problem of proliferating labels, as correlated systems
and
observers undergo measurement-type interactions with
newly-encountered
objects and instruments; it is suggested that this problem may be
resolved
by considering quantum field theory rather than the quantum
mechanics of
particles.
Comments: 18 pages, no figures. Minor changes
Subjects: Quantum Physics (quant-ph)
Journal reference: Found. Phys. Lett. 14 (2001) 301-322
Report number: WW-10184
Cite as: arXiv:quant-ph/0103079
<http://arxiv.org/abs/quant-ph/0103079>
just moves the problem from FTL signaling to FTL labeling.
Where is the FTL? I don't recall any suggestion that the "contagion" of
entangled
systems spreading themeselves in the MWI involves anything FTL.
Of course in Hilbert space there's no FTL because the system is just one
point and
when a measurement is performed it projects the system ray onto a mixture of
subspaces; spacetime coordinates are just some labels.
I thought there was no FTL in ordinary space, either? (I mean, none required
for the MWI?)
Right, but the state in Hilbert space is something like |x1 y1 z1 s1 x2 y2 z2 s2> and when
Alice measures s1 at (x1 y1 z1) then s2 is correlated at (x2 y2 z2). As I understand it
the MWI advocates say this isn't FTL because this is just selecting out one of infinitely
many results |s1 s2>. But the 'selection' has to pair up the spins in a way that violates
Bell's inequality.
In fact, it's generally assumed to be very, very STL (unless light itself is
involved). At great distances from the laboratory, one imagines that the
superposition caused by whatever we might do to cats in boxes would decay
to the
level of noise, and fail to spread any further.
That's an interesting viewpoint - but it's taking spacetime instead of
Hilbert space
to be the arena. If we take the cat, either alive or dead, and shoot it
off into
space then, as a signal, it won't fall off as 1/r^2.
No, but it will travel STL!
Sure. I was just commenting on the idea that the entanglement has a kind of limited range
because of 'background noise'. An interesting idea, similar to one I've had that there is
a smallest non-zero probability.
But if you want to get FTL, that's possible if Alice and Bob are near opposite sides of
our Hubble sphere when they do their measurements. They are then already moving apart
faster than c and will never be able to communicate - with each other, but we, in the
middle will eventually receive reports from them so that we can confirm the violation of
Bell's inequality.
Brent
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