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To: Gadsden1st
That you have (or have not) two dead cats was never the point. The point was that you ostensibly have a cat (or two cats, or N-cats) that are in a state of neither "aliveness" or "deadness." Contrary to what is printed in the popular literature, a number of physicists have had a lot of problems with Schroedinger's Cat over the years, including the question of whether the state of being alive or being dead even corresponds to an "Observable," in the quantum mechanical sense. Or if the cat's own self-awareness (cats are not particles, after all) fundamentally changes the experiment and so on.

Einstein had a much better analogy for mixed eignestates, and his version had no cat and did not involve potentially problematic metaphysical questions about whether there is a bounded Hermitean operator corresponding to "Life" or "Death." In his paradox, there is a keg of gunpowder in Schroedinger's Box. The question then becomes, when a quantum of radiation is introduced, is the gunpowder in an (un)exploded state or a mixed state of the two?

He argued that not even the most strident defender of quantum mechanics would remain in the room, secure in the belief that the gunpowder was in a mixed combination of eigenstates until the box was actually open.

Probably true.

That paradox is stripped of the silly aspects of the Schroedinger's Cat paradox, but for the same reason did not catch on in the imaginations of popular science writers who don't really understand science very well.

Assuming something that I don't believe -- that there's a quantum mechanical operator corresponding to "Life" -- for the purposes of advancing a hypothetical, if you could find a complementary physical property for a two-cat state, flipping that state in the near cat could kill the remote cat and bring the local cat back to life. Flipping that eigenstate again would bring the remote dead cat back to life, and kill the local one.

This is instructive in the instant case because no one believes physics can bring a dead entity back to life once truly dead. A perfectly good alternative explanation -- precisely because the two cats are indistinguishable -- is that you have merely teleported the dead cat to the live cat's former location, while teleporting the live cat back at the same time.

40 posted on 05/13/2012 10:23:44 AM PDT by FredZarguna (2.9979 times ten to the eight meters per second: not just a good idea, it's The Law.)
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To: FredZarguna
I hadn't heard the Einstein analogy, replacing the cat with gunpowder. It really does work much better to illustrate the actual realities of the situation. Of course, the observer in this case is the gunpowder (and the cat).

What convinced me that the state vectors really don't collapse until observed is the experiment with a laser pointer and three polarized sun-glass lenses.

Point a laser at a piece of polarized stuff oriented up. This will cut the intensity of the beam significantly by filtering out everything that isn't polarized up.

Downstream of that put another polarized piece oriented sideways (90 degrees) from the first piece. Given a sufficiently good quality of polarization this will pretty much totally stop the beam. This is all in accord with everyone's experience.

Now, what happens to the downstream beam (currently totally blocked) if we insert another polarized piece oriented at 45 degrees between the existing two? If the polarized pieces were just acting as filters the intuitive result would be exactly nothing.

This is not what happens. What does happen is that where there was darkness downstream there is now a pretty good beam. What happens at each polarization stage isn't a simple filtering, it is an honest to God observation, and it really does alter the polarization of the incoming photon.

I, for one, welcome our new Observing Overlords /.

41 posted on 05/13/2012 10:56:08 AM PDT by Mycroft Holmes (<= Mash name for HTML Xampp PHP C JavaScript primer)
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