Re: Is Schrödingers cat actually alive and dead at once?

Maja,

Your friend is mistaken; the cat is in what is called a "linear
superposition" of two quantum states: alive and dead.  It is not the
case that the cat has a definite state, but we just do not know what
that state is.  The cat is in both states simultaneously until someone
observes it; then the wavefunction collapses into one definite state or
the other.

There is an extensive Wikipedia page on Schroedinger's Cat
[ http://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat ]

One problem with understanding this example might be that such
superposed states are not observed macroscopically, that is for real
cats and other large objects, and so are unfamiliar to most people.

But quantum mechanical superpositions are made routinely with small
objects, like single rubidium atoms
[ http://jila.colorado.edu/content/sayonara-demolition-man ]
or superconducting quantum interference devices as in the article
"Schrodinger's cat comes into view"
[ http://physicsworld.com/cws/article/news/2815 ]


--Dr. Randall J. Scalise    http://www.physics.smu.edu/scalise