🚀 go-pugleaf

In article <mcirvin.713566546@husc8> mcirvin@husc8.harvard.edu (Mcirvin) writes:

>The commuting of observables at spacelike separation prevents
>spacelike communication via quantum entanglement precisely
>*because* the measurements act like eigenstate projectors.  An
>eigenstate of one such observable is always in an eigenspace of
>the other, so the order in which the projections occur doesn't
>matter, and there's no way one measurement can affect the result 
>of the other.

But that's simply not true.  In the straightforward Aspect type of
experiment, the observables commute, but the results of the
measurement are correlated, precisely because either measurement
projects the total wavefunction into an eigenstate of BOTH
observables.

In the usual case of two correlated, separated photons in a common
arbitrary polarisation state, the total wave function, in the H,V
basis, is

	|H1> |H2>  +  |V1> |V2>

(with usual normalisation stuff).  Now either measurement, at
M1 or M2 (presumed separate), is going to yield either pure |H1>|H2>
or pure |V1>|V2>.

This seems to me to be the flaw in most criticisms of Mr Sarfatti's
experiment: they assume that the wave functions are decoupled, or,
alternatively, that a measurement of one observable cannot affect
an observable of the "other" particle.  This is circular reasoning:
it is precisely that assumption that leads to Bell's inequality.