Re: TECH: Quantum Head Job

From: scerir (
Date: Thu Oct 11 2001 - 00:47:16 MDT

> >Perhaps Alice can build some _string_ performing
> >several measurements, each one on a different pair
> >of entangled particles, changing the basis every time.

> I believe this idea occurred to Nick Herbert (FASTER THAN LIGHT,
> ) many years ago, but he found it
> doesn't work either, and he withdrew the suggestion with some embarrassment.
> Damien Broderick

James T. Cushing [Quamtum Mechanics, Historical Contingency and the
Copenhagen Hegemony, Un. of Chicago Press, 1994, pag. 58 & 234] writes
that Mark Adkins suggested something like that.

Imo, the procedure works if those pairs of entangled particles are
almost identical (difficult condition).

Another possibility is that the evolution of the entangled system
is a bit non-linear (Weinberg, Gisin). That is because non-linearity
means distinguishability.

Let me point you to a very nice article by a philosopher:
    J. B. Kennedy
    "On the Empirical Foundations of the
    Quantum No-Signalling Proofs"
    Phil. Sci., 62, 543-560 (1995).
The point he makes is that any "proof" that QM cannot
support superluminal signalling, by using entanglement,
is essentially circular. Kennedy argued by way of digging into
the historical references, finding, for instance, von Neumann's
original motivation for introducing the tensor product rule,
for combining Hilbert spaces, it was essentially to block the
possibility of superluminal signalling.

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