Doug Renselle (renselle@on-net.net)
Tue, 10 Mar 1998 17:25:21 +0100
Dear Lila Squad Teammates,
The latest, 6Mar98 issue of Science Magazine has the quoted article
shown below. It tells the very essence of the Mechanics of Quanta (the
other MoQ -- MoQ II) in very brief form. This essence is Niels Bohr's
wave-particle (or quanton) complementarity. If you grasp the core of
this article you have a nice handle on MoQ II.
Note that this little tool/experiment is a very low cost version of the
one I described earlier on TLS where David E. Pritchard (MIT) diffracted
a sodium atom showing that atoms have a complementary wave nature. That
article, 'Beams of Stuff,' is in the December 1997 issue of Discover
Magazine.
Here's the article from SCIENCE Magazine. Enjoy! (Visit their site,
too!)
http://www.sciencemag.org - SCIENCE o VOL. 279 o 6 MARCH 1998 - p. 1457
'A Dial-Up Quantum Reality'
The lenient laws of quantum mechanics permit a lone electron to be in
two places at once-as long it avoids leaving a trace in its
surroundings. Now physicists have built an environment with a knob so
they can dial up the quirky quantum world or tune it out. The tabletop
device, built by physicist Mordehai Heiblum and colleagues at the
Weizmann Institute for Science in Rehovot, Israel, and described in last
week's Nature, pulls electrons through two adjacent corridors atop a
tiny microchip. If not watched--that is, if it can skirt through the
hallways without interacting with them--a single electron will go
through both at the same time and "recombine" when the pathways merge.
But add something that can detect which path the electron takes and
suddenly it cleans up its act, taking one corridor or the other like a
rat in a maze.
The Weizmann researchers rigged a kind of adjustable electric dam in one
of the channels. By adjusting an electric field near the channel, they
could, in effect, block part of the channel so that only a couple of
electrons could squeeze by. Roughly speaking, the higher the dam, the
more accurately they could tell whether an electron had passed by.
Raise it, and more electrons should be forced to take a single path.
"You can tell 'Oho!' one went by," says Heiblum. Lower it, he says, and
all the electrons should duplicitously slide through both channels at
once.
By watching the flow of electrons where the two corridors merged, the
researchers could count how many electrons had taken the single route
and how many had taken the double route. When they set the dam to
detect 5% of the electrons, about that same percentage took a solitary
corridor. As they lowered the dam, the strange hand of quantum
mechanics took over again until all electrons were taking both paths.
"It's a beautiful experiment," says Ned Wingreen, a physicist at the NEC
Research Institute in Princeton, New Jersey. In the everyday world, he
says, the environment that kills quantum behavior is unfathomably
complex, but "here, it's something you can understand perfectly" with
the taws of quantum mechanics. That suggests that any environment is
just a big quantum system, which brings up the strange question of
whether the universe itself is forever splitting off, taking multiple
paths at once. That's the logical conclusion, he says, "but it makes me
ill to think about it."
[by]
-David Kestenbaum
http://www.sciencemag.org - SCIENCE o VOL. 279 o 6 MARCH 1998 - p. 1457
Also, if you are interested the Loyola presentation pre-reading is
available now on the Quantonics site at:
http://www.quantonics.com/Level%203%20TQS%20Loyola%20MoQ%20Talk.html
Mtty,
Doug Renselle.
-- "Now, we daily see what science is doing for us. This could not be unless it taught us something about reality; the aim of science is not things themselves, as the dogmatists in their simplicity imagine, but the relations between things; outside those relations there is no reality knowable."By Henri Poincaré, in 'Science and Hypothesis,' p. xxiv, translated from French in 1905 by J. Larmor, published 1952 by Dover Publications.
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