From Richard J. Patrick
Your article about the suggested significance of randomness and so-called
nonlocality perpetuates a serious misunderstanding of the significance of
Schrödinger’s equation and hence of his cat.
Schrödinger’s cat possessed the fundamental characteristic of all
quantum cats—it was a dead or alive cat. In the same way the electron and
positron from the pion decay are quantum particles, so have either up or down
spin. To conserve spin one is in each state.
This has been so with every such pion decay anywhere in the Universe since
the big bang. Human observers came very late onto the scene and are not required
to be present for the quantum states to be resolved. Their sole involvement in
experiments is to collect and pass on information that both the electron and
positron knew from the instant of their creation—which has which spin.
Since each necessarily knew from the start which spin it had, there is no
instantaneous transfer of knowledge, for it travelled at the speed of the
particles from the point of the pion decay. The fundamental point is that
Schrödinger’s equation does not calculate a superposition of states but a
superposition of the probabilities of states— since it only ever
calculates probabilities.
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Observation resolves which of the probabilities is true. No more and no
less.
Mark Buchanan writes: It could indeed be so, but this wouldn’t change the
matter regarding nonlocality. If each particle “knows from the start” what spin
it has, then since ordinary quantum theory says nothing about such definite
spins, there must be some better (though perhaps unknown) theory that does.
Bell’s theorem shows that if the predictions of any such “hidden variables”
theory are to agree with those of quantum theory, then that theory must contain
some mechanism for nonlocal signalling between particles. Logically speaking,
whether or not you imagine the spins as being definite all the while, you must
accept some peculiar nonlocal links between them.
richard.patrick@btinternet.com
