McNelly.OsbuSouth@Xerox.ARPA (06/25/85)
I just read "In Search Of Schrodinger's Cat," a book by John Gribbin,
intended to introduce laymen to the subject of quantum mechanics. Does
anybody have any comments on the following excerpt, with respect to
info. travelling faster than the speed of light? The first (long)
paragraph gives technical details on how the experiment works, the
second (short) paragraph gives the results of the experiment: that
information was transmitted instantaneously, i.e., faster than the speed
of light.
[pp. 231-232]
"The Sussex team, headed by Terry Clark, has tacked the problem of
making measurements of quantum reality the other way around. Instead of
trying to construct experiments that operate on the scale of normal
quantum particles -- the scale of atoms or smaller -- they have
attempted to construct 'quantum particles' that are more nearly the size
of conventional measuring devices. Their technique depends upon the
property of superconductivity, and uses a ring of superconducting
material, about a half a centimeter across, in which there is a
constriction at one point, a narrowing of the ring to just one
ten-millionth of a square centimeter in cross section. This 'weak
link', invented by Brian Josephson who developed the Josephson Junction,
makes the ring of superconducting material act like an open-ended
cylinder such as an organ pipe or a tin can with both ends removed. The
Schrondinger waves describing the behavior of superconducting electrons
in the ring act rather like the standing sound waves in an organ pipe,
and they can be 'tuned' by applying a varying electromagnetic field at
radio frequencies. In effect, the electron wave around the whole of the
ring replicates a single quantum particle, and by using a sensitive
radio-frequency detector the team is able to observe the effects of a
quantum transition of the electron wave in the ring. It is, for all
practical purposes, as if they had a single quantum particle half a
centimeter across with which to work -- a similar, but even more
dramatic, example of the little bucket of superfluid helium mentioned
earler.
"The experiment provides direct measurements of single quantum
transitions, and it also provides further clear evidence of
non-locality. Because the electrons in the superconductor act like one
boson, the Schrodinger wave that makes a quantum transition is spread
out across the whole ring. The whole of this pseudoboson makes this
transition at the same time. It is NOT observed that one side of the
ring makes the transition first, and that the other side only catches up
when a signal moving at the speed of light has had time to travel around
the ring and influence the rest of the 'particle.'"
[The author continues, making observations about potential applications
in computers and communications. He also mentions that work is underway
on another "macroatom" which is in the form of a straight cylinder six
meters long.]