From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: FEYNMAN 12
Organization: Whole Earth 'Lectronic Link
Date: Fri, 16 Oct 1992 08:10:38 GMT


Feynman 12
p.71 "Nature had seemed so continuous. Technology, however, made
discreteness and discontinuity a part of everyday experience: gears and
ratchets creating movement in tiny jumps; telegraphs that digitized
information in dashes and dots. What about the light emitted by
matter?....The German physicist Max Planck pursued this idea ... and
announced in 1900 that it required a awkward adjustment to the conventional
way of thinking about energy. His equations produced the desired results
[explaining the distribution of energy of 'black body' thermal radiation
with wavelength as a function of absolute temperature] only if one supposed
that radiation was emitted in lumps, discrete packets called quanta. He
calculated a new constant of nature, the indivisible unit underlying these
lumps. It was aunit, not of energy, but of the product of energy and time -
the quantity called action.

Five years later Einstein used Planck's constant to explain another puzzle,
the photoelectric effect, in which light absrobed by a metal knocks
electrons free and creates an electric currnt. ...

in 1913 Niels Bohr, a younf Dane working in Ernest Rutherford's laboratory
in Manchester, England, proposed a new model of the atom built on these
quantum underpinnings. ... Without a quantum theory... The result would be
continuous radiation and the ... collapse of the atom in on itself....

Heisenberg wrote privately [p.72] 'My whole effort is to destroy without a
trace the idea of orbits' [of electrons around the tiny massive nucleus of
the atom].

It was in 1925. Heisenberg set out to pursue his conception wherever it
might lead, and it led to an idea so foreign and surprising that 'he was
really scared'. It seemed that Heisenberg's quantities, numbers arranged in
matrices [square arrays in this case], violated the usual commutative law
of multiplication that says a times b equals b times a... There were
consequences. Equations of this form could not specify both mentum and
position with definite ['infinite' better than 'definite' - JS] precision.
A measure of uncertainty had to be built in." p.73

['observables' that can be measured by detectors are represented by
matrices. A theorem shows that if two observables have matrices that do not
commute, then, the product of their precisions (root mean square deviations
from their statistical averages over repeated measurements on an ensemble
of identically prepared systems) cannot be less than essentially Planck's
constant (ignore factor of 1/2). That is, noncommutativity is sufficient
for an uncertainty principle or 'incompatibility' between measurements of
different observables.

However, it is not generally appreciated by physicists today that non-
commutativity while sufficient is not necessary for incompatibility.
Indeed, Schrodinger showed in 1930 that, under certain conditions of
'entanglement' even commuting observables can be forced to obey an
uncertainty principle!  This is essential for understanding communication
on the nonlocal quantum spin connection!  The traditional idea of causality
that spin observables for space-like separated particlesl commute - is not
sufficient to exclude the transfer of bits of information between the spin
measurements if the particles are in an entangled state at their creation.
In fact, however, local decoding of a useful message requires a
transformation of the initial entangled state into a disentangled state.
Without this disentanglement the encoded information cannot be accessed in
a useful way.