NetNews Usenet Archive 1992 #16/NN_1992_16.iso/spool/sci/physics/12112

Internet Message Format | 1992-07-31 | 3.9 KB

Path: sparky!uunet!sun-barr!cs.utexas.edu!ut-emx!johncobb
From: [e-mail] (John W. Cobb)
Newsgroups: sci.physics
Subject: Re: Aristotle and the Modern Physicist
Message-ID: <[e-mail]>
Date: 31 Jul 92 16:54:34 GMT
References: <[e-mail]> <[e-mail]> <mcirvin.712271293@husc8> <[e-mail]> <[e-mail]>
Sender: [e-mail]
Reply-To: [e-mail] (John W. Cobb)
Organization: The University of Texas at Austin
Lines: 61

In article <[e-mail]>, [e-mail]
(RING, DAVID WAYNE) writes:
|>[e-mail] (Aephraim M. Steinberg) writes...
|>>                                             Certainly, the cat alone is
|>>not in a coherent superposition, nor is the radioactive nucleus, taken
|>>alone, but together, they are.  (Assuming they have not yet interacted
|>>with anything else.)
|>
|>Well, getting a cat into a pure state is quite an achievement! ;-)
|>
I always thought that was the precise reason for Schrodinger constructing
the Cat paradox. He showed that the usual notions about quantum measurement
implied that is a bit absurd to talk about preparing something as macroscopic
as a cat into a specific quanutm state, i.e. an eigenvalue of the live/dead
measurment. (Is there an annihilation operator for this? :} )

If you accept the definition that measurement occurs when the "irreversible
act of amplification" (Is this a Bohr quote?) occurs then I would say that
the wavefunction collapsed when the silicon detector INSIDE the box fired
amplifying the decay event from a single particle to a stream of millions
or billions of electrons cascading across the potential.

I developed an intuition to explain this "curious world". The detector
amplifies small events to create vastly different time asymptotic states
(no current flow/current flow). So the detector is unstable and right at
a bifurcation point. Thus its global behavior is determined by small
perturbations. So very small perturbations can be measured by the
effect they have on the measuring apparatus. This is "the irreversible
act of amplification". It makes great sense when I 'fess up to my
prejudice towards nonlinear dynamical systems. Nonlinear systems can
exhibit both perturbation amplification and time reversal asymmetry.
Moreover, when I look at most quantum measuring devices I see nonlinear
behavior. The Silicon barrier Diode is unstable and electrons undergo
multiplication (read non-linear). Bubble chambers when they are measuring
are out of thermal equilibrium and the energy of the particle is used as
a nucleation point for nonlinear bubble evolution.


So my prejudice says the cat dies when the electrons start the cascade.
It is at that point that the wavefunction collapses. The cat is alive
or dead before we open the box since the measurment as interpreted as the
act of irreversible amplification has aready occurred. The only thing that
happens when we open the box is we learn what has already happened. This
rids us of the troublesome notion that consciousness is important. Here
measurement can occur without any conscious observor.


This all has great intuitive appeal to me. But so what? Is there any
science here? Well I need to make a prediction that differs from current
orthodoxy (otherwise I am only introducing another "interpreation" of
how events occur). Now how does one form this viewpoint into a testable
prediction? I am presently unable to think of an experiment whose outcome
depends on the state of the cat after the (possible) detector firing but
before the lid is open. In fact such an experiment may be impossible, even
in principle because it would then be considered a de facto opening of the
lid. Well I'm a little stumped here. I think that if I knew how to
quantize non-integrable systems that I might be able to answer how this
notion my predict anything new.

john w .cobb
[e-mail]