Dennis Gabor was a British physicist and electrical engineer whose invention of holography won him the Nobel Prize in Physics for 1971. He made important contributions to information theory with the first attempts to measure the "quantity" of information.
In 1946, he published a classic paper
entitled '
Theory of Communication', in which the Fourier transform
theory used in wave mechanics was applied to
the frequency-time (
f-t) domain of the communication
engineer, with the suggestion that a signal occupying an
elementary area of
Δf Δt = 1/2 could be regarded as a "unit
of information", which he called a "
logon".
Before Gabor, signal frequencies, whether audible, electrical, or visual, were analyzed
either as a function of time or as multiple frequencies in a Fourier analysis. He now proposed to do both simultaneously. He found that when he increased discrimination in one of these, the uncertainty in the other increased.
He recognized the connection with quantum uncertainty, without referring explicitly to
Werner Heisenberg's uncertainty principle.
ΔpΔx = h
Indeed, if you multiply Gabor's expression by Planck's constant
h, you get the expression for quantum uncertainty in terms of energy and time, since
E = hf.
hΔfΔt =ΔEΔt = h/2
Gabor's "logon" was cited by
Donald MacKay as one of the earliest "measures" of information. (The other was that of
R. A. Fisher.)
|
