[ExI] John A. Wheeler
ablainey at aol.com
ablainey at aol.com
Fri Apr 18 02:22:13 UTC 2008
I am sure you realised that 'shutter speed' referred to the timeframe of measurement and not the use of cameras. Just thought i'd clarify that in case?someone has visions of me taking snapshots down a microscope.?Thanks for the references, It is a subject which interests me , but I previously?have not had sufficient time to study to it to any serious degree. It is on my to do list :o)
Do you have any references to more recent works or current experiments?
I have to admit that I like the idea of a fractalic universe and as a nuts and bolts type of person, my own idea of an experiment that would show the position of electrons. Or at least show they don't occupy every available position. would be to fire discrete particles through the electron path at a perpendicular angle. Any impact would show the presence of an electron and a lack of impact would prove an absence. no? just like shooting between the blades of a ww2 biplane.
Useless for measurement without disrupting the system being measured, but it would prove something about the electron position.
From: scerir <scerir at libero.it>
To: ExI chat list <extropy-chat at lists.extropy.org>
Sent: Thu, 17 Apr 2008 15:31
Subject: Re: [ExI] John A. Wheeler
I have always thought that a large problem
in quantum measurement is the 'shutter speed'. [etc.]
# While position measurements are not performed
using cameras and shutters , it is true there is an
impossibility of any sharp distinction between the
behaviour of atomic objects and the interaction
with the measuring instruments which serve to define
the conditions under which the phenomena appear.
This conspiracy has different names and faces, like
Bohr's complementarity , WAY theorem, KS contextuality.
 The theoretical treatment of a very fast shutter requires (imo)
a time-dependent Schroedinger equation, and it is (imo) a difficult
subject. See,ie, Marcos Moshinshy 'Diffraction in Time', Physical Review,
vol. 88, n. 3, (1952), pages 625-631.
 'However, since the discovery of the quantum of action,
we know that the classical ideal cannot be attained
in the description of atomic phenomena. In particular,
any attempt at an ordering in space-time leads to
a break in the causal chain, since such an attempt
is bound up with an essential exchange of momentum
and energy between the individuals and the measuring
rods and clocks used for observation; and just this
exchange cannot be taken into account if the measuring
instruments are to fulfil their purpose. Conversely,
any conclusion, based in an unambiguous manner upon the
strict conservation of energy and momentum, with
regard to the dynamical behaviour of the individual
units obviously necessitates a complete renunciation
of following their course in space and time'.
-N.Bohr, 'Atomic Theory and the Description of Nature',
pp. 97-8, Cambridge University Press, 1934
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