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| From: Yoda Oz |
16/03/99
10:23:11
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| Subject: Schrodinger's Cat |
post id:
3981
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What is this theory all about?
What is a linear superposition? I read this in a book called "The Physics
of Star Trek" by LM Krauss.
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| From: spOOk |
16/03/99
10:51:37
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| Subject: re: Schrodinger's
Cat |
post id:
3983
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Regarding linear superposition -
see Jerry's question from a while back on quantum entanglement.
The
cat thing is an attempt to show the mind boggling conundrums associated
with quantum reality via a paradox. It's not really a theory by
itself.
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| From: James Richmond
(Avatar) |
16/03/99
23:10:12
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| Subject: re: Schrodinger's
Cat |
post id:
4113
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The Schrodinger cat thought
experiment involves having a cat in a box, along with a vial of poison
gas. The vial can be broken open, releasing the gas, by a hammer attached
to a trigger mechanism. The trigger mechanism consists of an unstable
particle of some sort, say a radioactive atom, which has a probability of,
say 1/2 of decaying in any particular hour. If the particle decays, the
hammer breaks the vial, releasing the gas and killing the cat. If it
doesn't, the cat lives. (Schrodinger obviously wasn't a cat
lover.)
The rules of quantum mechanics (standard Copenhagen
interpretation) say that until someone looks at, or measures the
state of the particle, it can exist in a superposition of states.
The base states for the particle are "decayed" and "not decayed", but it
can also exist in a combination of the two states, in a sense, being
decayed and not decayed simultaneously.
Since the particle
determines whether or not the cat lives, we can carry the quantum state
through to the cat level and say that before anyone opens the box at the
end of the hour, the cat can exist in the superposition of states "live
cat" and "dead cat", in a sense being both alive and dead at the same
time.
Not many people today seriously believe that this type of
thing actually happens. Neither did Schrodinger. The question that arises,
then, is that since there is a lot of evidence that this sort of thing
does happen for atomic sized objects, how to we make the transition
from the odd quantum world to our common sense, everyday macroscopic
world?
JR
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