X-Message-Number: 8592
From: Andre Robatino <>
Subject: Re: CryoNet #8587 - #8589
Date: Sat, 13 Sep 97 19:39:24 EDT

> Message #8589
> Date: Fri, 12 Sep 1997 21:26:45 -0700 (PDT)
> From: John K Clark <>
> Subject: Digital Shakespeare
> 
<snip>

> Can you think of any measurable quality that's directly correlated with a 

> unique quantum wave function? I can't. It contains no energy and isn't even a
> probability, it's the square root of a probability, a calculating device.

  _Any_ state directly corresponds to a specific set of outcomes for some
complete set of measurements.  The statement that the state is |psi>
has the observable consequence that it guarantees that when performing any of
the corresponding measurements, one will get the corresponding value.  Other
input states may have a nonzero probability of yielding the same values for
each of the same set of measurements (and if this happens, then the output
state is |psi>), but no other input state _guarantees_ it.  The statement

1) if one starts from state |psi>, one is guaranteed to get value m_i for any
measurement M_i in a particular complete set of measurements {M_i}

is just as meaningful as

2) if one starts from state |psi>, then the probability of finding the particle
in volume dV near the point x is |psi(x)|^2 dV

since both are verified the same way - statistically, by creating the state
|psi> a large number of times and doing the appropriate experiments on it.
In fact, the first statement is slightly more meaningful, since it could be
falsified with a single counterexample, while falsifying the second would
require a large number of trials and one gets into philosophical issues about
the meaning of probability.

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