Re: Quantum Cryptography can not work

Unruh wrote:
Were it arbitrary you should be able to come up with a situation in which
one could use the entanglement to signal faster than light.

And, of course, if one could do *that*, there would indeed be a
contradiction between relativity and quantum mechanics.

However, while the conclusion that entanglement smells bad, and is
therefore absurd and false, is wrong, I am not devoid of all sympathy
for those who express these confused views.

One cannot, even by means of quantum entanglement, use known, existing
forces to signal faster than light. If known, existing forces could do
that, then the bizarre phenomena predicted by special relativity would
not have had to exist.

But that does not necessarily mean that the final truth of nature is
"nonlocal". That is hard to even define, let alone imagine.

Instead, the actual truth can be something simpler; something that
more pedestrian minds could sympathize with.

How is it that angular momentum is conserved when we measure the
polarization of one photon in a pair, the other one being measured
also as a measurement event having a spacelike relation to that
measurement?

Well, the two photons ARE signalling each other faster-than-light. But
they're using the X force, not something we've seen directly yet in
our laboratories. When we discover the X force, *then* we can use it
to distinguish true rest from other inertial frames, *as required by
special relativity*, as well as using it to signal (and maybe travel)
faster than light.

When the X force is hidden, then no faster than light signalling is
possible, and the EPR paradox just is an extreme case of this - when,
because the X force is not out in the open, no FTL signalling is
possible, BUT Nature still uses it for its own purposes, proving
logically that the hidden X force is really there!

This lets people accept that relativity and quantum mechanics are both
true *without* doing violence to a pedestrian, local, and mechanistic
view of the Universe, which is natural to some temperaments. I see no
reason to denounce that way of viewing the Bell inequality, EPR, and
so on.

Let those of imaginative temperaments embrace nonlocality; perhaps
someday they can provide it with semantic content for the rest of us.

Let those with more pedestrian temperaments view the EPR paradox, now
proved to be part of reality, as an enigmatic hint of a hidden path to
FTL travel.

Let them understand the physics involved clearly, however, and realize
that it's only a hint - no direct exploitation is possible, unless
some *other* experiment turns up the X force in a more manifest
fashion, in which it exhibits violation of the equivalence of all
inertial frames, which the EPR experiment does not. So the task for
our time is to be alert to anomalies turning up in the literature, any
attempt to fund FTL research in the form of carrying out experiments
is premature.

So there is a way for people uncomfortable with quantum entanglement
to avoid discomfort and yet agree with the observed physical
phenomena! Physics is big, and should have room for people with all
temperaments!

John Savard

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