Re: PHYS; Quantum Teleportation

Mitchell Porter (
Tue, 16 Dec 1997 13:26:16 +1000 (EST)

Tony Csoka wrote

> The quantum teleportation effect and the uncertainty principle etc. could
> be explained by looking at the effect from more than four dimensions. If
> we assume that the universe is also made up of, say, a fifth spatial
> dimension that has collapsed down to an infinitely small point, then
> although from our point of view two particles may appear to be separated
> by billions of light years, in the higher dimension, they could be in the
> very same place. This is analogous to writing "A" and "B" a few inches
> apart on a flat piece of paper ( 2 dimensions) and then folding the paper
> (through the 3rd dimension) so that A and B connect. (sorry, this is a bit
> a tired analogy, but it works!)
> Similarly, if there are up to 11 or even 22 dimensions, as some physicists
> believe, that have collapsed down to infinitely small points, then all
> places in the universe are in a very certain way "at the same place at the
> same time". This is a "spooky" thought.

Suppose you get a sheet of paper and roll it up from bottom to top.
The left side is not any closer to the right side than it was.
In the same way, having compactified extra dimensions does not
in itself mean that A is closer to B than it looks. I don't
entirely discount the possibility of what you're talking about,
but it would require geometries of a sort not presently contemplated.

I think you might have a better chance trying to explain
nonlocality with wormholes. In that case one doesn't need higher
dimensions, just an unusual connectivity (topology) for space.
Another possibility is loops in time (closed timelike curves),
in which nonlocal correlation between A and B is due to a local
causal chain starting at A and proceeding off to C in one
temporal direction, and another local causal chain starting
at C and proceeding back to B in the opposite temporal direction.
(Or due to more complicated temporal zigzags.)

There is a paper (
which claims to derive "the logic of quantum mechanics" from
time loops in classical general relativity - but I'll only
believe it when someone actually obtains the full Schroedinger
equation that way.

Finally, there is simply the possibility that the world truly
is nonlocal - causally nonlocal, and/or ontologically nonlocal,
with distributed entities whose states are not reducible to
the union of localized properties. In the latter case, my
question is, where does *locality* come from? At what point,
under what conditions, are there truly localized entities?
I don't think quantum mechanics can answer that question -
in general, entanglement ends only with the "collapse of
the wavefunction" or the "projection of the state vector",
and that's the part of the theory whose interpretation
is contentious.