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At 8:28 AM -0600 1/28/98, Jim Choate wrote:
Forwarded message:
Date: Tue, 27 Jan 1998 23:44:50 -0800 From: Steve Schear <schear@lvdi.net> Subject: Re: Planetary rovers, SETI and other musings, was Re: update.356 (fwd)
I guess I'm over my head in such matters. From my, admitedly, shallow understanding of wave function collapse, etc., I was under the apparent misimpression that once collapsed (e.g., by Alice entangling a 'modulation' photon M (of a known polarization) with one member (photon A) of an entangled pair, one of which was sent to Alice and the other (photon B) which was sent to Bob, photon B's polarization state was determined and could not subsequently be altered by Bob's measurement with his receiver. Could you recommend a good article which explain this paradox to a non-quantum mechanic?
The state is determined *at the time of collapse*. Once the collapse occurs the synchronization is no longer present and subsequent events can indeed alter the polarization of one particle without altering the other. Simply bouncing that photon via refraction off a surface can alter the polarization.
If that is the case, I still don't understand why and out-of-band signal is required. If the sender collapses the wave function shortly before the signal reaches the intended receiver its unlikely to have changed polarization again. --Steve