From: "Dan Minette" <[EMAIL PROTECTED]>
> >
>
> > For a quantum system we can calculate the wavefunction to arbitrary
> accuracy.
> >
>
> We can, until the wavefunction collapses. Then we can calculate no
further
> until we determine which eigenstate it collapsed into.
>
Wavefunction collapse is an arrtifact of the Copenhagen interpretation.
It works when doing calculations but, as Schrodinger's cat shows, it
is not really sound.
Decoherence is an approach that suggets the wavefunction doesn't
actually collapse, it's just that for classical systems all trace of
interfeerence is washed out by interactions with the rest
of the universe.
> > We have two particles in a rectangular box whose wavefunctions
> > can be expanded in terms of the energy eigenfunctions. The actual
> > interaction term is complicated but it can be approximated by the
> > probability of collisions in any pair of states and the probability
> > of transitions between states at the moment of collision. On doing
> > this you get a set of first order ODEs for the probability of
> > being in each energy eigenstate, which is a computable problem,
> > solvable to arbitrary accuracy.
> I think we really did misscommunicate here. We do know the probability
of
> finding the balls, but we cannot predict where the balls will be. After
10
> seconds, a minute for sure, all we can say is that the balls will be on
the
> table (assuming the table is, say, 5 meters by 5 meters).
You are not asking a meaningful question.
You can either do a fully classical calculation, in which case the positions
are theoretically predictable, or you can do a fully quantum calculation,
in which case the probablity distribution of the position can be predicted
to
arbitary accuracy.
Either way events are theoretically predictable to arbitary accuracy.
--
Robert
