fireandwater said:
Could you please define "superposition"?
In quantum mechanics a system is described by a state function, which we'll call |A>. This statefunction may be made up of any number of eigenfuctions (edit: that should read "made up of any linear combination of eigenfunctions), which are linearly independant functions in a hermitian vector space. Let's say a state function |A> had two eigenfunctions |a> and |b>. In quantum mechanics you are required to treat the state function |A> as if it were in a superposition of states |a> + |b>.
In other words, when determining the statistics of a quantum system, you treat it as if it were in
all possible states. Classically a system is in a state, and you need only measure it to figure out which one. This is what the Schroedinger Cat is all about; classicaly, we figure if you have radiated the cat, it is alive or dead. Quantum mechanically, you have to treat the cat as if it were both alive and dead until you measure it.
To be honest, the Shroedinger Cat paradox is a rather mediocre thought experiment because a living organism is an exceedingly complex system, and the cat should be thought of as any vast number of possible states, many of which would leave it alive or dead. Consider instead the research
this gentleman works on (he has a description of it in his Aug 18th post). He works with circuits which function as quantum qubits. They deal every day with the fact that the circuits can have current flowing one way, the other, or a superposition of the two states. It's quantum superposition on a larger scale.
That paper on decoherence I linked to above may be more help than I've been.
