Norman Samish wrote:
> I've been reading about "spooky action at a distance" at
> http://www.ncsu.edu/felder-public/kenny/papers/bell.html and several other
> sites.
"Spooky action-at-a-distance" is a catchy but misleading description of
EPR-Bell type quantum correlations because there is no effective "action"
or signalling passing between the two correllated particles or subsystems
involved. "Passion-at-a-distance" is an entirely better description of what
takes place: a certain statistical resilience between the values of time-like
separated subsystems that remain bound in an entangled state...
>
> I'm told that non-locality is a phenomenon that is proven. A review of
> experiments makes it clear that "spooky action at a distance is part of
> nature." But doesn't this violate the rule that nothing can travel faster
> than the speed of light? Well, no, it does not - because of a technicality.
Not a exactly a "technicality" in the sense you intend it. The rule is that "no
signal can travel faster than c" but there is no signalling involved in the
reservation of these correlations.
>
> Nevertheless, how might one of "entangled" particles, even though separated
> by light-years, react instantaneously to a measurement done to its sibling?
> I've seen no hypothesis. The answer is, apparently, one of many Quantum
> Mysteries.
It is only a mystery if you try and reason classically about it. Quantum
mechanics
makes this type of correlation a more "natural" thing than, say, the causal
succession
of events linking action to effect. It is this later one that needs to be
explained from
the Qunatum Mechanical point-of-view.
> This is unsatisfying. I would like to hear speculations on non-locality.
>
> We are told that string theory needs 11 dimensions - could it be, for
> example, that there is another dimension in which the entangled particles
> are adjacent to each other?
The type of unsatisfaction that you display can be mended with what are
called "non-local hidden-variable theories", which unfortunately must
invoke other "unpleasantnesses", such as non-local potentials. Other
dimensions may seem an intuitively appealing option out of this connundrum
but not the kind of extra dimensions invoked by string theory, which must
be compactified (="curled up locally") at some point. Large extra dimensions
may be more accommodating but somehow that has not been tried as of yet.
If the EPR correlations were "actions" rather than "passions" that would be
somewhat easier to implement. But it is hard to understand why these extra
dimensions would have been constrained in this particular way...
>
> Norman
Kindly,
-Joao
--
Joao Pedro Leao ::: jleao.domain.name.hidden
Harvard-Smithsonian Center for Astrophysics
1815 Massachussetts Av. , Cambridge MA 02140
Work Phone: (617)-496-7990 extension 124
Cell-Phone: (617)-817-1800
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"All generalizations are abusive (specially this one!)"
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Received on Wed Nov 12 2003 - 12:35:17 PST